阅读说明：本技术 一种高稳定性的射频功率放大器 (High-stability radio frequency power amplifier ) 是由 武振宇 贾斌 张晓强 于 2018-08-06 设计创作，主要内容包括：本申请公开了一种高稳定性的射频功率放大器,包括预放大器、功率输出级、电压电流转换电路、电源电压补偿电路和电流稳定电路。所述电压电流转换电路包括运算放大器、一个低压差稳压器、环路稳定辅助电路和反馈电路；环路稳定辅助电路和反馈电路串联在运算放大器的输出端和同相输入端之间。本申请在电压电流转换电路中引入环路稳定辅助电路和反馈电路,用来提供额外的负反馈支路,以确保在射频功率放大器的整个PVT工作区间内的负反馈电流控制环路能够稳定可靠工作。还引入了隔离电路和电流稳定电路,提高了射频功率放大器的稳定性。(The application discloses radio frequency power amplifier of high stability, including preamplifier, power output stage, voltage current conversion circuit, mains voltage compensating circuit and current stabilization circuit. The voltage-current conversion circuit comprises an operational amplifier, a low dropout regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier. The loop stabilizing auxiliary circuit and the feedback circuit are introduced into the voltage-current conversion circuit and used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop in the whole PVT working interval of the radio-frequency power amplifier can work stably and reliably. An isolation circuit and a current stabilizing circuit are also introduced, so that the stability of the radio frequency power amplifier is improved.)

1. A high-stability radio frequency power amplifier is characterized by comprising a preamplifier, a power output stage, a voltage-current conversion circuit, a power supply voltage compensation circuit and a current stabilization circuit;

the preamplifier is used for amplifying a radio frequency input signal in advance;

the power output stage comprises a power amplifying circuit and a current sampling circuit; the power amplification circuit is used for carrying out power amplification on the radio-frequency signal amplified in advance under the control of the control voltage to obtain output power; the current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain a sampling current;

the voltage-current conversion circuit comprises an operational amplifier, a low dropout regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the voltage-current conversion circuit is used for converting the control voltage into reference current, comparing the reference current with the sampling current of the power output stage through the operational amplifier, and accessing a comparison result into a low-dropout voltage regulator which provides power supply voltage for the preamplifier; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier;

the power supply voltage compensation circuit is used for compensating output power change caused by power supply voltage change of the power output stage;

the current stabilizing circuit is used for adjusting the current flowing through the power transistor in the power output stage according to the temperature change.

2. The high stability rf power amplifier of claim 1, wherein the preamplifier includes an inverter and a feedback resistor; the inverter is formed by sequentially cascading a PMOS transistor and an NMOS transistor between the power supply voltage of the preamplifier and the ground, the grid electrodes of the two transistors are connected to be used as the input end of the inverter, and the drain electrodes connected with the two transistors are used as the output end of the inverter; the feedback resistor is connected between the input end and the output end of the phase inverter.

3. The high-stability radio frequency power amplifier according to claim 1, wherein the power amplifying circuit is formed by sequentially cascading an inductor, a common source transistor and a common gate transistor between a power supply voltage of the power output stage and the ground; the cascode transistor and the common-gate transistor form a first cascode structure;

the current sampling circuit comprises a second cascode structure, and the second cascode structure and the first cascode structure form a cascode current mirror structure and are used for sampling current flowing through two power transistors in the power amplification circuit; the current sampling circuit further comprises a second current mirror structure, and the second current mirror structure further reduces the intermediate sampling current output by the cascode current mirror to obtain the final sampling current output by the current sampling circuit.

4. The high stability rf power amplifier of claim 1, wherein the voltage-to-current conversion circuit further comprises a filtering unit, a voltage generating unit; the control voltage is connected to the inverting input end of the operational amplifier through the filtering unit, and the sampling current of the power output stage generates feedback voltage at the non-inverting input end of the operational amplifier through the voltage generating unit; the output end of the operational amplifier is connected with the grid electrode of the adjusting tube of the low dropout regulator; the drain of the low dropout regulator supplies power to the preamplifier.

5. The high stability RF power amplifier of claim 4, wherein the filter unit comprises a filter resistor and a filter capacitor, the control voltage is connected to the inverting input terminal of the operational amplifier through the filter resistor, and the inverting input terminal of the operational amplifier is further connected to ground through the filter capacitor.

6. The high stability RF power amplifier of claim 4, wherein the voltage generator is a parallel branch of a first resistor and a second resistor, one end of the parallel branch is connected to ground, and the other end of the parallel branch is connected to the non-inverting input of the operational amplifier.

7. The high stability rf power amplifier of claim 1, wherein the loop stability assist circuit comprises an auxiliary low dropout regulator; the grid electrode of an adjusting tube of the auxiliary low dropout regulator is connected with the output end of the operational amplifier, the source electrode of the adjusting tube is connected with the power supply voltage, the drain electrode of the adjusting tube is grounded through a load resistor on one hand, and the drain electrode of the adjusting tube is also connected to the non-inverting input end of the operational amplifier through a feedback circuit on the other hand.

8. The high stability rf power amplifier of claim 6, wherein the voltage to current converter circuit further comprises a PVT curve adjustment circuit; the PVT curve adjusting circuit is formed by adding an NMOS transistor or a PMOS transistor which is connected in series into a diode structure between a second resistor and the ground or between a non-inverting input end of the operational amplifier and the second resistor.

9. The high stability rf power amplifier of claim 1, wherein the voltage to current converter circuit further comprises a miller compensation circuit; the Miller compensation circuit is connected between the grid electrode and the drain electrode of the adjusting tube of the low dropout regulator and comprises a Miller capacitor which is connected with a zero setting resistor in series.

10. The high stability rf power amplifier of claim 6, wherein the voltage to current converter circuit further comprises a temperature compensation circuit; the temperature compensation circuit is formed by connecting a first resistor and a second resistor in series by adopting a positive temperature coefficient resistor and a negative temperature coefficient resistor.

11. The high stability rf power amplifier of claim 1, wherein the supply voltage compensation circuit comprises a differential amplifier circuit and a current mirror; the differential amplifying circuit tracks the change of the power supply voltage, and the current mirror generates compensating current with the same change trend as the power supply voltage.

12. The high stability rf power amplifier of claim 1, wherein the current stabilization circuit comprises a positive temperature coefficient current source, a transistor fifteen, and a transistor sixteen; the positive temperature coefficient current source and the transistor fifteen are sequentially connected in series between a power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor fifteen are connected and connected with a positive temperature coefficient current source; the source electrode of the transistor fifteen is connected with the ground of the current stabilizing circuit; the gate of the transistor sixteen is connected with the gate of the transistor fifteen, the drain is connected with the non-inverting input end of the operational amplifier, and the source is connected with the ground of the current stabilizing circuit.

13. The high stability rf power amplifier of claim 1, wherein the current stabilization circuit comprises a negative temperature coefficient current source, transistors seventeen to twenty; the negative temperature coefficient current source and the transistor seventeen are sequentially connected in series between a power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor seventeen are connected and are connected with a negative temperature coefficient current source; the source electrode of the transistor seventeen is connected with the ground of the current stabilizing circuit; the grid electrode of the eighteen transistor is connected with the grid electrode of the seventeenth transistor, the drain electrode of the eighteen transistor is connected with the drain electrode of the nineteen transistor, and the source electrode of the eighteen transistor is connected with the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor nineteen are connected, and the source electrode of the transistor nineteen is connected with a power supply of the current stabilizing circuit; the grid of the transistor twenty is connected with the grid of the transistor nineteen, the source electrode is connected with the power supply of the current stabilizing circuit, and the drain electrode is connected with the non-inverting input end of the operational amplifier.

14. The high stability rf power amplifier of claim 1, wherein the pre-amplifier, the power output stage, the voltage-to-current conversion circuit, the power supply voltage compensation circuit and the current stabilization circuit have isolation circuits between their respective power supplies.

15. The high stability rf power amplifier of claim 1, wherein the pre-amplifier, the power output stage, the voltage-to-current conversion circuit, the power supply voltage compensation circuit and the current stabilization circuit have isolation circuits between their respective grounds.

16. The high stability rf power amplifier as claimed in claim 14 or 15, wherein the isolation circuit is formed by connecting an isolation resistor, an isolation inductor, and an isolation capacitor in parallel between two objects to be isolated.

17. The high-stability radio frequency power amplifier according to claim 14 or 15, wherein the isolation circuit is formed by connecting an isolation resistor and an isolation inductor in parallel between two objects to be isolated, and the isolation capacitor is connected between one object to be isolated and a separate ground.

18. The high stability rf power amplifier of claim 14 or 15, wherein the isolation circuit is an end-to-end diode structure, one isolation diode is connected in reverse between two objects to be isolated, and the other isolation diode is connected in forward between two objects to be isolated.

Technical Field

The present invention relates to a radio frequency power amplifier in a mobile terminal, and more particularly, to a radio frequency power amplifier including a power control circuit.

Background

In the mobile terminal, the radio frequency power amplifier is used for amplifying the power of the radio frequency signal, and then the radio frequency signal is fed to the antenna to be transmitted outwards. In movingIn the communication process between the mobile terminal and the base station, due to the fact that the distance between the mobile terminal and the base station is different, or due to the fact that an antenna of the mobile terminal is shielded, power control is often required to be carried out on the transmitting power output by a radio frequency power amplifier in the mobile terminal. For example, in a radio frequency power amplifier for 2G (second generation mobile communication technology), a power control circuit is included, which controls a voltage V_rampThe output power of the radio frequency power amplifier is continuously controlled.

In order to realize the control of the output power of the radio frequency power amplifier, the power control circuit needs to detect the output power of the radio frequency power amplifier first, and then a negative feedback control loop is constructed to realize the stable control of the output power of the radio frequency power amplifier. Common power control circuits with high integration and low cost include a voltage detection scheme and a current detection scheme.

The power control circuit adopting the voltage detection scheme can only be applied to a radio frequency power amplifier working in a saturation region, and has poor precision at low output power.

The power control circuit adopting the current detection scheme can be applied to a radio frequency power amplifier working in a saturation region and/or a linear region and has higher efficiency. The power control circuit adopting the current detection scheme is generally characterized in that a small resistor, for example less than 0.1 omega, is connected in series in a final stage path of a radio frequency power amplifier; and controlling the output power of the radio frequency power amplifier by detecting the voltage difference between the two ends of the small resistor. The scheme needs small resistors with accurate resistance values, is high in cost and poor in integration level, and extra power consumption can be generated on the small resistors connected in series, so that the efficiency of the radio frequency power amplifier is reduced.

In addition, the RF power amplifier is controlled by the voltage V under the normal working state_rampThe control is periodically turned on and off, thereby generating a switch spectrum (switch spectrum), which presents a large challenge to the power control curve of the rf power amplifier. The working current of the rf Power amplifier varies from 0 to 2A during the whole PVT (Power VS Time), which presents a great challenge to the stability of the control loop. The radio frequency power amplifier works in a radio frequency band, power and ground of each module are not ideal, and positive feedback is easy to generate and vibrate. Especially, the working temperature range of the radio frequency power amplifier is between-40 ℃ and 125 ℃, the performance of each module of the radio frequency power amplifier can be greatly changed at different temperatures, and oscillation is easy to occur.

Disclosure of Invention

The technical problem to be solved by the application is to provide a radio frequency power amplifier comprising a power control circuit, wherein the power control circuit adopting a current detection scheme has the characteristics of low cost, high reliability and high stability.

In order to solve the technical problem, the high-stability radio frequency power amplifier comprises a preamplifier, a power output stage, a voltage-current conversion circuit, a power supply voltage compensation circuit and a current stabilization circuit.

The preamplifier is used for amplifying a radio frequency input signal in advance.

The power output stage comprises a power amplifying circuit and a current sampling circuit; the power amplification circuit is used for carrying out power amplification on the radio-frequency signal amplified in advance under the control of the control voltage to obtain output power; the current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain sampling current.

The voltage-current conversion circuit comprises an operational amplifier, a low dropout regulator, a loop stabilizing auxiliary circuit and a feedback circuit; the voltage-current conversion circuit is used for converting the control voltage into reference current, comparing the reference current with the sampling current of the power output stage through the operational amplifier, and accessing a comparison result into a low-dropout voltage regulator which provides power supply voltage for the preamplifier; the loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end and the non-inverting input end of the operational amplifier;

the power supply voltage compensation circuit is used for compensating output power change caused by power supply voltage change of the power output stage;

the current stabilizing circuit is used for adjusting the current flowing through the power transistor in the power output stage according to the temperature change.

The technical effect that this application obtained is: a loop stabilizing auxiliary circuit and a feedback circuit are introduced into the voltage-current conversion circuit and are used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop in the whole PVT working range of the radio frequency power amplifier can work stably and reliably. The voltage-current conversion circuit controls the current of the power output stage of the current working frequency band through negative feedback, and the higher efficiency of the radio frequency power amplifier is achieved. The power supply voltage compensation circuit ensures that the output power of the radio frequency power amplifier does not change along with the change of the power supply voltage. The current stabilizing circuit improves the stability of the radio frequency power amplifier in the whole working temperature range.

Preferably, the preamplifier includes an inverter and a feedback resistor; the inverter is formed by sequentially cascading a PMOS transistor and an NMOS transistor between the power supply voltage of the preamplifier and the ground, the grid electrodes of the two transistors are connected to be used as the input end of the inverter, and the drain electrodes connected with the two transistors are used as the output end of the inverter; the feedback resistor is connected between the input end and the output end of the phase inverter. This is a specific implementation of a preamplifier, by way of example only. The degeneration resistor is used to determine the dc bias point and provide the required input impedance for the rf power amplifier.

Preferably, the power amplifying circuit is formed by sequentially cascading an inductor, a common source transistor and a common gate transistor between a power supply voltage of the power output stage and the ground; the common source transistor and the common gate transistor form a first common source and common gate structure. The current sampling circuit comprises a second cascode structure, and the second cascode structure and the first cascode structure form a cascode current mirror structure and are used for sampling current flowing through two power transistors in the power amplification circuit; the current sampling circuit further comprises a second current mirror structure, and the second current mirror structure further reduces the intermediate sampling current output by the cascode current mirror to obtain the final sampling current output by the current sampling circuit. This is a specific implementation of the power output stage, by way of example only. The power amplification circuit adopts a cascode structure I, which can improve the voltage swing, and two current mirror structures are used for sampling the output current of the power transistor.

Preferably, the voltage-current conversion circuit further comprises a filtering unit and a voltage generating unit; the control voltage is connected to the inverting input end of the operational amplifier through the filtering unit, and the sampling current of the power output stage generates feedback voltage at the non-inverting input end of the operational amplifier through the voltage generating unit; the output end of the operational amplifier is connected with the grid electrode of the adjusting tube of the low dropout regulator; the drain of the low dropout regulator supplies power to the preamplifier. The filtering unit can reduce the signal interference of the irrelevant frequency band. The voltage generation unit may convert a sampling current of the power output stage into a feedback voltage so that the control voltage and the feedback voltage are compared in the operational amplifier.

Preferably, the filtering unit includes a filtering resistor and a filtering capacitor, the control voltage is connected to the inverting input terminal of the operational amplifier through the filtering resistor, and the inverting input terminal of the operational amplifier is further grounded through the filtering capacitor. This is a specific implementation of the filtering unit, merely as an example.

Preferably, the voltage generating unit is a parallel branch of a first resistor and a second resistor, one end of the parallel branch is grounded, and the other end of the parallel branch is connected with the non-inverting input end of the operational amplifier. This is a specific implementation of the voltage generating unit, merely as an example.

Further, the loop stabilizing auxiliary circuit comprises an auxiliary low dropout regulator; the grid electrode of an adjusting tube of the auxiliary low dropout regulator is connected with the output end of the operational amplifier, the source electrode of the adjusting tube is connected with the power supply voltage, the drain electrode of the adjusting tube is grounded through a load resistor on one hand, and the drain electrode of the adjusting tube is also connected to the non-inverting input end of the operational amplifier through a feedback circuit on the other hand. The loop-stabilizing auxiliary circuit implements an additional negative feedback branch.

Further, the voltage-current conversion circuit further comprises a PVT curve adjustment circuit; the PVT curve adjusting circuit is formed by adding an NMOS transistor or a PMOS transistor in series connection in a diode structure between a second resistor and the ground or between a non-inverting input end of the operational amplifier and the second resistor. The PVT curve adjustment circuit is advantageous for improving the switching spectrum of the radio frequency power amplifier.

Further, the voltage-current conversion circuit further comprises a miller compensation circuit; each Miller compensation circuit is connected between the grid electrode and the drain electrode of an adjusting tube of a low dropout regulator and comprises a Miller capacitor which is connected with a zero setting resistor in series. The miller compensation circuit helps to improve the stability of the negative feedback current control loop.

Further, the voltage-current conversion circuit further comprises a temperature compensation circuit; the temperature compensation circuit is formed by connecting a first resistor and a second resistor in series by adopting a positive temperature coefficient resistor and a negative temperature coefficient resistor. The temperature compensation circuit helps to ensure that the output power of the power output stage of the radio frequency power amplifier is stable at different temperatures.

Preferably, the power supply voltage compensation circuit comprises a differential amplification circuit and a current mirror; the differential amplifying circuit tracks the change of the power supply voltage, and the current mirror generates compensating current with the same change trend as the power supply voltage. This is a specific implementation of the supply voltage compensation circuit, by way of example only.

Preferably, the current stabilizing circuit comprises a positive temperature coefficient current source, a transistor fifteen and a transistor sixteen; the positive temperature coefficient current source and the transistor fifteen are sequentially connected in series between a power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor fifteen are connected and connected with a positive temperature coefficient current source; the source electrode of the transistor fifteen is connected with the ground of the current stabilizing circuit; the gate of the transistor sixteen is connected with the gate of the transistor fifteen, the drain is connected with the non-inverting input end of the operational amplifier, and the source is connected with the ground of the current stabilizing circuit. This is a specific implementation of a current stabilization circuit, by way of example only. The sixteen transistors and the fifteen transistors form a current mirror structure, and the positive temperature coefficient current source obtains an adjusting current which is in direct proportion to the temperature through the current mirror structure and injects the adjusting current into the non-inverting input end of the operational amplifier, so that the voltage of the non-inverting input end of the operational amplifier is pulled down to the ground, and the stability of the radio frequency power amplifier is improved.

Preferably, the current stabilization circuit comprises a negative temperature coefficient current source, transistors seventeen to twenty; the negative temperature coefficient current source and the transistor seventeen are sequentially connected in series between a power supply and the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor seventeen are connected and are connected with a negative temperature coefficient current source; the source electrode of the transistor seventeen is connected with the ground of the current stabilizing circuit; the grid electrode of the eighteen transistor is connected with the grid electrode of the seventeenth transistor, the drain electrode of the eighteen transistor is connected with the drain electrode of the nineteen transistor, and the source electrode of the eighteen transistor is connected with the ground of the current stabilizing circuit; the grid electrode and the drain electrode of the transistor nineteen are connected, and the source electrode of the transistor nineteen is connected with a power supply of the current stabilizing circuit; the grid of the transistor twenty is connected with the grid of the transistor nineteen, the source electrode is connected with the power supply of the current stabilizing circuit, and the drain electrode is connected with the non-inverting input end of the operational amplifier. This is another specific implementation of the current stabilization circuit, by way of example only. Eighteen and seventeen transistors form a first current mirror structure, twenty and nineteen transistors form a second current mirror structure, and a negative temperature coefficient current source obtains an adjusting current inversely proportional to the temperature through the two current mirror structures and extracts the adjusting current from the non-inverting input end of the operational amplifier, so that the power supply of the current stabilizing circuit is pulled down to the non-inverting input end of the operational amplifier, and the stability of the radio frequency power amplifier is improved.

Furthermore, isolation circuits are arranged between respective power supplies of the preamplifier, the power output stage, the voltage-current conversion circuit, the power supply voltage compensation circuit and the current stabilization circuit in pairs. The interference among the modules can be reduced and avoided, and the stability of the radio frequency power amplifier is improved.

Furthermore, isolation circuits are arranged between the respective grounds of the preamplifier, the power output stage, the voltage-current conversion circuit, the power supply voltage compensation circuit and the current stabilization circuit in pairs. The interference among the modules can be reduced and avoided, and the stability of the radio frequency power amplifier is improved.

Preferably, the isolation circuit is formed by connecting an isolation resistor, an isolation inductor and an isolation capacitor in parallel between two objects to be isolated. This is a specific implementation of the isolation circuit, by way of example only.

Preferably, the isolation circuit is formed by connecting an isolation resistor and an isolation inductor in parallel between two objects to be isolated, and the isolation capacitor is connected between one object to be isolated and a separate ground. This is another specific implementation of the isolation circuit, by way of example only.

Preferably, the isolation circuit is a diode structure connected end to end, one isolation diode is connected in reverse between two objects to be isolated, and the other isolation diode is connected in forward between the two objects to be isolated. This is yet another specific implementation of the isolation circuit, by way of example only.

The high-stability radio frequency power amplifier provided by the application can be widely applied to the control of the voltage V_rampThe radio frequency power amplifier for controlling the output power has the characteristics of stable and reliable work and has the following beneficial effects.

Firstly, the control voltage V is converted by a voltage-current conversion circuit_rampConversion to a reference current I_rampAnd constructing a negative feedback current control loop to control the current of the power output stage of the radio frequency power amplifier, thereby realizing higher efficiency.

And secondly, a loop stabilizing auxiliary circuit and a feedback circuit are introduced into the voltage-current conversion circuit and used for providing an additional negative feedback branch circuit so as to ensure that a negative feedback current control loop in the whole PVT working interval of the radio-frequency power amplifier can work stably and reliably and effectively avoid oscillation of the negative feedback current control loop.

And thirdly, a PVT curve adjusting circuit, a Miller compensation circuit and a temperature compensation circuit are further integrated in the voltage-current conversion circuit, and the voltage-current conversion circuit has the characteristics of high integration level and reliable and stable work. The PVT curve adjusting circuit is beneficial to adjusting the PVT curve of the radio frequency power amplifier and improving the switching spectrum of the radio frequency power amplifier. The miller compensation circuit helps to improve the stability of the negative feedback current control loop. The temperature compensation circuit helps to ensure that the output power of the power output stage of the radio frequency power amplifier is stable at different temperatures.

And fourthly, the output power of the radio frequency power amplifier is enabled not to change along with the change of the power supply voltage through the power supply voltage compensation circuit.

And fifthly, the stability of the radio frequency power amplifier in the whole working temperature range is improved through the current stabilizing circuit.

And sixthly, isolation circuits are inserted between the power supplies of the modules and between the grounds, so that the interference between the modules is reduced, and the stability of the radio frequency power amplifier is improved.

Drawings

Fig. 1 is a schematic circuit diagram of an embodiment of a high-stability rf power amplifier according to the present application.

Fig. 2 is a circuit diagram of one embodiment of the preamplifier of fig. 1.

Fig. 3 is a circuit schematic of one embodiment of the power output stage of fig. 1.

Fig. 4 is a circuit configuration diagram of the first embodiment of the voltage-current conversion circuit in fig. 1.

Fig. 5 is a circuit configuration diagram of a second embodiment of the voltage-current conversion circuit in fig. 1.

Fig. 6 is a schematic circuit diagram of an embodiment of the temperature compensation circuit in fig. 4 and 5.

Fig. 7 is a circuit configuration diagram of an embodiment of the power supply voltage compensation circuit in fig. 1.

Fig. 8 is a circuit configuration diagram of the first embodiment of the current stabilization circuit in fig. 1.

Fig. 9 is a circuit configuration diagram of a second embodiment of the current stabilization circuit in fig. 1.

Fig. 10 is a schematic diagram of power supply isolation between modules of the high-stability rf power amplifier of the present application.

Fig. 11 is a schematic diagram of isolation between the modules of the high-stability rf power amplifier of the present application.

Fig. 12a to 12c are schematic circuit structures of three embodiments of the isolation circuit.

The reference numbers in the figures illustrate: v_inIs a radio frequency input signal; v_preIs made by pre-placingA large radio frequency signal; v_outOutputting a signal for radio frequency; v_rampIs a control voltage; v_ldoIs the supply voltage of the preamplifier; gnd _ pre is the ground of the preamplifier; v_cc、V_{cc_ps}Is the supply voltage of the power output stage; gnd _ ps is the ground of the power output stage; i is_rampIs a reference current; i is_compTo compensate for the current; i is_senseIs a sampling current; m is a MOS transistor; r_fIs a feedback resistor; l is an inductor; v_cascodeIs the gate bias voltage of the common-gate transistor; FB is a feedback node; v_fbIs a feedback voltage; v_{cc_vi}A power supply for the voltage-current conversion circuit; gnd _ vi is the ground of the voltage-current conversion circuit; OP is an operational amplifier; m_AThe low dropout regulator is an adjusting tube of the low dropout regulator/an adjusting tube of the auxiliary low dropout regulator; m_BA transistor of the PVT curve adjustment circuit; r_pA resistor with a positive temperature coefficient; r_nA negative temperature coefficient resistance; v_{cc_comp}A power supply for the supply voltage compensation circuit; gnd _ comp is the ground of the supply voltage compensation circuit; d is a diode; i is_ssIs a tail current source; v_{cc_ptat}A power supply for the current stabilization circuit; gnd _ ptat is the ground of the current stabilization circuit; i is_pt、I_ctIs a current source; i is_ptat、I_ctatTo adjust the current; c is a capacitor; ISO is an object that needs to be isolated.

Detailed Description

Referring to fig. 1, an embodiment of a high stability rf power amplifier is provided. The high-stability radio frequency power amplifier shown in this embodiment includes a preamplifier, a power output stage, a voltage-to-current conversion circuit, a power supply voltage compensation circuit, and a current stabilization circuit.

The preamplifier is used for inputting a radio frequency signal V_inPre-amplifying to obtain larger dynamic range, outputting a pre-amplified RF signal V_pre。

The power output stage includes a power amplification circuit and a current sampling circuit. The power amplifying circuit is used for controlling the voltage V_rampUnder the control of (2), one path is passed throughPre-amplified RF signal V_preAmplifying power to obtain output power V_out. The output power V_outAfter passing through the matching circuit, the antenna emits the signal. The current sampling circuit is used for sampling the current flowing through the power transistor in the power output stage to obtain a sampling current I_sense。

The voltage-current conversion circuit comprises an operational amplifier, a Low-dropout regulator (LDO), a loop stabilization auxiliary circuit and a feedback circuit. The voltage-current conversion circuit is used for converting the control voltage V_rampConversion to and control voltage V_rampProportional reference current I_rampAnd through the operational amplifier and the sampling current I of the power output stage_senseThe comparison is carried out, the result of the comparison (i.e. the output of the operational amplifier) is connected to a low dropout regulator which supplies a supply voltage V to the preamplifier_ldo. The loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end of the operational amplifier and the feedback node FB (i.e. the non-inverting input end of the operational amplifier) to provide an additional negative feedback branch to ensure that the negative feedback current control loop can stably and reliably operate in the whole PVT operating range of the radio frequency power amplifier.

The power supply voltage compensation circuit is used for compensating the power supply voltage V of the power output stage_ccOutput power V caused by variation_outThe variations are compensated for so that different supply voltages V_ccOutput power V of lower power output stage_outAnd remain constant.

The current stabilizing circuit is used for further adjusting the current flowing through the power transistor in the power output stage so as to improve the stability of the radio frequency power amplifier in the whole working temperature range.

At the position of the feedback node FB in FIG. 1, there is a reference current I injected by the voltage-to-current conversion circuit_rampWith compensation current I drawn by the supply voltage compensation circuit_compSampled current I drawn by the power output stage having the current operating frequency band_senseWith the regulated current I injected by the current-stabilizing circuit_ptatAnd I is_ramp+I_ptat＝I_comp+I_sense. When controlling the voltage V_rampAt rise, reference current I_rampIncreasing therewith, assuming a compensating current I_compAnd regulating the current I_ptatAre not changed, then the sampling current I of the power output stage_senseThis, in turn, reflects from another point of view that the current through the power transistor in the power output stage increases, so that the output power V of the rf power amplifier is increased_outIncreasing; and vice versa.

In addition, the current I is adjusted when the temperature decreases_ptatDecrease, assuming reference current I_rampAnd a compensation current I_compAre not changed, then the sampling current I of the power output stage_senseAnd then decreases, which reflects from another perspective that the current flowing through the power transistor in the power output stage decreases, so that the output power V of the rf power amplifier is reduced_outDecrease; and vice versa. This shows that the current stabilization circuit can improve the stability of the radio frequency power amplifier at different temperatures.

In the high-stability rf power amplifier shown in fig. 1, an amplification path is formed from the preamplifier, the power output stage, the matching circuit to the antenna. On the amplification path, the radio frequency input signal V_inFirstly enters a preamplifier to obtain a pre-amplified radio frequency signal V_preThen enters a power output stage for power amplification to obtain a radio frequency output signal V_outAnd then transmitted out by the antenna after passing through the matching circuit.

Meanwhile, the power output stage, the voltage-current conversion circuit and the preamplifier are sequentially connected to form a negative feedback current control loop of the radio frequency power amplifier. When controlling the voltage V_rampWhen the voltage rises, the voltage-current conversion circuit provides the power supply voltage V for the preamplifier_ldoStep-up, pre-amplifier output voltage V_preThe bias voltage of the power output stage is increased, so that the current flowing through the power transistor in the power output stage is increased accordingly. In this case, the output power V of the power output stage is firstly adjusted_outIncreased therewith and embodying the control voltage V_rampOutput power V to RF power amplifier_outThe regulating action of (c); on the other hand, the sampling current I of the power output stage_senseThen increases, thereby making the feedback voltage V of the feedback node FB_fbAnd (4) rising. Feedback voltage V_fbThe power supply voltage V provided for the pre-amplifier is pulled up by the operational amplifier in the voltage-current conversion circuit_ldoThe gate voltage of the regulating tube of the low dropout regulator makes the power supply voltage V of the preamplifier_ldoThere is a tendency to decrease. Thus, a complete current control loop is formed through negative feedback, and the closed-loop control of the output power of the radio frequency power amplifier is realized.

Referring to fig. 2, an embodiment of the preamplifier of fig. 1 is shown. The preamplifier includes an inverter and a feedback resistor R_f. The inverter is at the supply voltage V of the preamplifier_ldoAnd a ground gnd _ pre of the preamplifier, and a PMOS transistor M is sequentially cascaded between the preamplifier and the ground gnd _ pre₁And NMOS transistor II M₂Formed of two transistors M₁And M₂Are connected as the input of an inverter, two transistors M₁And M₂Is connected as the output of the inverter. Feedback resistor R_fConnected between the input and output of the inverter. The input end of the phase inverter receives a radio frequency input signal V_inThe output end of the phase inverter outputs a path of pre-amplified radio frequency signal V to the outside_pre. Feedback resistor R_fIs used to determine the dc bias point and provide the required input impedance for the rf power amplifier. The same circuit configuration may be used for preamplifiers for different frequency bands.

Referring to fig. 3, one embodiment of the power output stage of fig. 1 is shown. The power output stage includes a power amplification circuit and a current sampling circuit.

The power amplifier circuit is at the power supply voltage V of the power output stage_{cc_ps}An inductor L1 and a transistor four M are sequentially cascaded between the power output stage and the ground gnd _ ps₄And transistor tri-M₃. Transistor three M₃Adopting common source connection mode, transistor four M₄Adopting common grid connection mode, transistor three M₃And transistor four M₄And forming a cascode structure I. One path of pre-amplified radio frequency signal V_preInto transistor three M₃By a transistor of three M₃Drain access transistor of₄At the source of the transistor IV₄The drain electrode outputs the radio frequency signal V after power amplification_out. The power amplification circuit adopts a cascode structure, so that the swing of output voltage can be improved. The inductor L1 is preferably a choke inductor, also called a choke (choke inductor), and functions to pass dc and block ac.

The current sampling circuit is a power supply voltage V at the power output stage_{cc_ps}And a transistor seven M is sequentially cascaded between the power output stage and the ground gnd _ ps₇Six transistors, six M₆And transistor five M₅And also comprises a transistor eight M₈. Transistor five M₅Adopting common source connection mode, transistor six M₆Adopting common gate connection mode, transistor five M₅And transistor six M₆And forming a cascode structure II. Transistor five M₅And transistor three M₃Is connected with the grid of the transistor six M₆And transistor four M₄The grid of the grid is connected, and a second common-source common-gate structure and a first common-source common-gate structure form M: 1 cascode current mirror structure for sampling two power transistors M flowing through a power amplification circuit₃、M₄The current of (2). The middle sampling current output by the cascode current mirror is reduced by M times than the current flowing through a power transistor in the power amplification circuit. Transistor seven M₇Is connected with the drain electrode and is connected with the transistor six M₆Of the substrate. Transistor seven M₇And transistor eight M₈Are all connected with the power supply voltage V of the power output stage_{cc_ps}Transistor eight M₈Is connected to the feedback node FB and draws a sample current I from the feedback node FB_sense. Transistor eight M₈And transistor seven M₇The grid electrodes of the N: 1, further reducing the intermediate sampling current output by the cascode current mirror by N times to obtain the final sampling current I output by the current sampling circuit_sense. In this way it is possible to obtain,sampled current I obtained by power output stage_senseIncreasing the M multiplied by N is the current flowing through the power transistor, and the proportionality coefficient M and/or N can be adjusted by selecting element parameters, so that the stability of the negative feedback current control loop and the efficiency of the radio frequency power amplifier are optimized.

Wherein, the transistor is three M₃Transistor four M₄Transistor five M₅Six transistors, six M₆For example, are all NMOS transistors. Transistor seven M₇Eight transistors, eight M₈For example, both PMOS transistors. Common gate connected transistor quad M₄Six transistors, six M₆With gate bias voltage V_cascode。

Referring to fig. 4, a first embodiment of the voltage-to-current conversion circuit of fig. 1 is shown. The voltage-current conversion circuit comprises a filtering unit, a voltage generating unit, an operational amplifier OP, a low dropout regulator, a loop stabilizing auxiliary circuit and a feedback circuit. Control voltage V_rampThrough a filter resistor R₀Connected to the inverting input of the operational amplifier OP, which is further connected to the inverting input of the operational amplifier OP via a filter capacitor C₀And (4) grounding. Filter resistor R₀And a filter capacitor C₀The filtering unit is constructed. Sampling current I of power output stage_senseThe output is at a resistor R₁And a resistance two R₂On the parallel branch (assuming now that the transistor M is indicated by a dashed line)_BDoes not exist), a feedback voltage V is generated at the position of the feedback node FB_fbConnected to the non-inverting input to an operational amplifier OP. Resistance one R₁And a resistance two R₂The parallel branches of (a) constitute a voltage generating unit. The output end of the operational amplifier OP is connected to the loop stabilizing auxiliary circuit and the adjusting tube M_AA gate electrode of (1). The loop stabilizing auxiliary circuit and the feedback circuit are connected in series between the output end of the operational amplifier OP and the feedback node FB and are used for providing an additional negative feedback branch outside the negative feedback current control loop so as to ensure that the negative feedback current control loop in the whole PVT working interval of the radio frequency power amplifier can work stably and reliably. Adjusting pipe M_AForming a low dropout regulator. Adjusting pipe M_ASource electrode ofSupply voltage V connected with voltage-current conversion circuit_{cc_vi}The drain electrode is connected with the power supply end of the preamplifier to supply a power supply voltage V to the preamplifier_ldo. The voltage-current conversion circuit also has the advantages of simple circuit, complete functions, high integration level and stable and reliable work.

When controlling the voltage V_rampAt the rise, the output voltage V of the operational amplifier OP_gIs lowered, which adjusts the tube M_AThe gate voltage of the transistor M is reduced, thereby reducing the voltage of the transistor M_AThe drain voltage of the preamplifier is the power supply voltage V_ldoStep-up, pre-amplifier output voltage V_preThe gate voltage of the power output stage is increased, so that the current flowing through the power transistor in the power output stage is increased accordingly. This causes the sampled current I of the power output stage to be_senseThen increases, thereby making the feedback voltage V of the feedback node FB_fbAnd (4) rising. The high gain of the final negative feedback current control loop causes the feedback voltage V of the feedback node FB_fbFinally stabilized at the control voltage V_ramp。

Referring to fig. 5, a second embodiment of the voltage-to-current conversion circuit of fig. 1 is shown. The difference of the second embodiment compared to the first embodiment is only that a specific implementation of the loop-stabilizing auxiliary circuit is given. The loop stabilizing auxiliary circuit is mainly realized by an auxiliary low dropout regulator. Adjusting tube M of auxiliary low dropout regulator_A2The grid of the operational amplifier is connected with the output end of the operational amplifier OP, and the source of the operational amplifier is connected with the power supply voltage V of the voltage-current conversion circuit_{cc_vi}The drain electrode is connected to the load resistor R_LThe drain is connected to the ground gnd _ vi of the voltage-current conversion circuit and the feedback node FB through the feedback circuit to realize an additional negative feedback branch.

Preferably, the feedback circuit in fig. 4 and 5 is a resistor, or any combination of series and/or parallel of a plurality of resistors.

In the same voltage-current conversion circuit shown in fig. 4 and 5, the following structure may be optionally included.

Preferably, the voltage-current conversion circuit further comprises a PVT curve adjusting circuitAnd (4) a way. The PVT curve adjusting circuit is arranged at a resistor II R₂An NMOS transistor M is added between the ground and the NMOS transistor M in series connection_BThis is indicated by a broken line in fig. 4 and 5. The NMOS transistor M_BConnected in a diode configuration, i.e. with the gate and drain connected and connected to a resistor two R₂(ii) a The source is grounded. When controlling the voltage V_rampSmaller than NMOS transistor M_BAt the threshold voltage of (2), the resistance (II R)₂The branch is disconnected and only has a resistor R₁The branch is connected into the circuit, which makes the feedback voltage V of the feedback node FB_fbStep-up the output voltage V of the operational amplifier OP_gRaising, pre-amplifier supply voltage V_ldoReducing, pre-amplifier output voltage V_preReduced, thereby reducing the transistor tri-M in the power output stage₃So as to flow through the power transistor M₃、M₄The current of (2) is reduced. When controlling the voltage V_rampGreater than or equal to NMOS transistor M_BAt the threshold voltage of (2), the resistance (II R)₂The branch is connected into the circuit, which makes the feedback voltage V of the feedback node FB_fbReducing the output voltage V of the operational amplifier OP_gReducing, pre-amplifier supply voltage V_ldoStep-up, pre-amplifier output voltage V_preStep up, thereby raising the transistor tri M in the power output stage₃So as to flow through the power transistor M₃、M₄The current of (2) increases. This helps to improve the switching spectrum of the radio frequency power amplifier. Based on the same principle as that shown in fig. 4 and 5, the PVT curve adjusting circuit may change the NMOS transistor connected as a diode structure into the PMOS transistor connected as a diode structure, or change the NMOS transistor connected as a diode structure into the PMOS transistor connected as a diode structure, or into the PMOS transistor connected as a diode structure with the non-inverting input terminal of the operational amplifier OP and the resistor two R₂An NMOS transistor or a PMOS transistor (not shown) connected in series to form a diode structure is added in between.

Preferably, the voltage-current conversion circuit further comprises a first miller compensation circuit. The Miller compensation circuit is connected with the adjusting tube M_AFor example, a miller capacitor is connected in series with a zero setting resistor; fig. 4 and 5 show broken lines. Shown in FIG. 5The loop stabilizing auxiliary circuit optionally further comprises a second miller compensation circuit. The second Miller compensation circuit is connected with the adjusting tube M of the auxiliary low dropout regulator_A2For example, a miller capacitor is connected in series with a zero setting resistor; indicated in fig. 5 with dashed lines. The miller compensation circuit improves the phase margin of the negative feedback current control loop through pole separation, thereby improving the stability of the negative feedback current control loop.

Preferably, the voltage-current conversion circuit further comprises a temperature compensation circuit. Referring to fig. 6, an embodiment of the temperature compensation circuit of fig. 4 and 5 is shown. The temperature compensation circuit is a resistor R in the graph of FIG. 4 and FIG. 5₁Resistance two R₂All adopt positive temperature coefficient resistor R_pAnd a negative temperature coefficient of resistance R_nAre connected in series. By adjusting the resistance R of the positive temperature coefficient_pAnd a negative temperature coefficient of resistance R_nThe temperature coefficient of the sampling current of the power transistor can be adjusted, and then the temperature coefficient of the output power of the radio frequency power amplifier can be adjusted, so that the output power which does not change along with the temperature can be obtained.

Referring to fig. 7, an embodiment of the power supply voltage compensation circuit of fig. 1 is shown. The power supply voltage compensation circuit comprises a differential amplification circuit and a current mirror. The differential amplifying circuit mainly comprises a transistor nine M₉To twelve transistors₁₂And tail current source I_ssAnd (4) forming. Transistor nine M₉Gate pass resistance of tri-R₃Supply voltage V connected to supply voltage compensation circuit_{cc_comp}Also through a plurality of diodes D connected in series₁To D_nClamped at the lowest operating voltage (e.g., 3.5V). Transistor ten M₁₀Gate pass resistance of (iv)₄Supply voltage V connected to supply voltage compensation circuit_{cc_comp}. Transistor nine M₉Source of (1), transistor (ten M)₁₀Is connected to the source of the power supply and passes through a tail current source I_ssAnd the ground gnd _ comp of the power supply voltage compensation circuit is connected. Eleven M transistors₁₁Source electrode of (1), transistor twelve M₁₂Are all connected to a supply voltage compensation circuitSupply voltage V_{cc_comp}. Eleven M transistors₁₁Gate and drain of (1), transistor twelve M₁₂Are connected. Eleven M transistors₁₁Drain of the transistor nine M₉Of the substrate. Transistor twelve M₁₂Drain of the transistor ten M₁₀And is connected to transistor thirteen M₁₃Of the substrate. The current mirror is mainly composed of a transistor thirteen M₁₃And a transistor fourteen M₁₄And (4) forming. Thirteen M transistors₁₃Source electrode of (1), transistor fourteen M₁₄Are all connected to the supply voltage V of the supply voltage compensation circuit_{cc_comp}. Thirteen M transistors₁₃Gate of and transistor fourteen M₁₄Are connected. Transistor fourteen M₁₄Is drawing a compensation current I from the feedback node FB_comp. When the power supply voltage V of the power supply voltage compensation circuit_{cc_comp}At the time of rising, the transistor is ten M₁₀Increased current of transistor twelve M₁₂So that the current of the transistor thirteen M is reduced₁₃By the current mirror circuit, the transistor is fourteen M₁₄The current of (2) also increases. The compensation current I thus drawn from the feedback node FB_compIncrease when the reference current I_rampAnd regulating the current I_ptatAll of which are constant, so that the sampling current I_senseThe current flowing through the power transistor is reduced, so that the output power V of the radio frequency power amplifier is reduced_outDecrease; and vice versa. Thus, the differential amplifier circuit tracks the change of the power supply voltage, and the current mirror generates the compensation current with the same trend as the change of the power supply voltage. The power supply voltage compensation circuit can be used for compensating the power supply voltage V of the power supply compensation circuit_{cc_comp}When the change occurs, the change of the output power of the radio frequency power amplifier caused by the change is compensated, so that the output power of the radio frequency power amplifier under different power supply voltages is kept constant.

It should be particularly noted that in the high-stability rf power amplifier provided by the present application, the power supplies of the modules are connected together at the dc part, and isolation circuits are added in pairs at the ac part. Thus, of modulesThe dc voltage of the power supply is varied synchronously. Supply voltage V of supply voltage compensation circuit to supply compensation circuit_{cc_comp}Is compensated for, i.e. corresponds to the supply voltage V of the power output stage_{cc_ps}The output power is compensated by compensating the direct current change.

Referring to fig. 8, a first embodiment of the current stabilization circuit of fig. 1 is shown. The current stabilization circuit shown in this embodiment includes a positive temperature coefficient current source I_ptFifteen M transistor₁₅And a transistor sixteen M₁₆. Positive temperature coefficient current source I_ptE.g. by bandgap reference voltage generation, which is in conjunction with transistor fifteen M₁₅Power supply V connected in series in current stabilizing circuit_{cc_ptat}And ground gnd ptat of the current stabilization circuit. Transistor fifteen M₁₅Is connected with the drain electrode and is connected with a positive temperature coefficient current source I_pt. Transistor fifteen M₁₅Is connected to ground gnd _ ptat of the current stabilizing circuit. Sixteen M transistors₁₆Of a gate-connected transistor fifteen M₁₅And the drain is connected to the feedback node FB, and the source is connected to ground gnd _ ptat of the current stabilization circuit. Sixteen M transistors₁₆And transistor fifteen M₁₅Form a current mirror structure, a positive temperature coefficient current source I_ptThe current mirror structure obtains an adjusting current I which is in direct proportion to absolute temperature_ptatThe regulated current I_ptatFrom the feedback node FB to ground.

The current stabilization circuit shown in FIG. 8 adjusts the current I in proportion to the temperature when the temperature decreases_ptatDecrease, assuming reference current I_rampAnd a compensation current I_compAre not changed, then the sampling current I of the power output stage_senseThis in turn means that the current through the power transistor in the power output stage decreases, so that the output power V of the radio frequency power amplifier is reduced_outAnd decreases. At the same time, the feedback voltage V of the feedback node FB_fbAdjusting tube M of low dropout regulator in step-up, voltage current conversion circuit_AGate voltage V of_g(i.e., the output terminal voltage of operational amplifier OP) is increased, lowering the voltage of the LDOOutput voltage V_ldo. Therefore, the power supply voltage of the preamplifier is reduced, the gain of the preamplifier is reduced, and the stability of the radio frequency power amplifier is improved.

Referring to fig. 9, a second embodiment of the current stabilization circuit of fig. 1 is shown. The current stabilization circuit shown in this embodiment includes a negative temperature coefficient current source I_ctSeventeen transistors₁₇To transistor twenty M₂₀. Negative temperature coefficient current source I_ctE.g. by bandgap reference voltage generation, with transistor seventeen M₁₇Power supply V connected in series in current stabilizing circuit_{cc_ptat}And ground gnd ptat of the current stabilization circuit. Seventeen transistors₁₇Is connected with the drain electrode and is connected with a negative temperature coefficient current source I_ct. Seventeen transistors₁₇Is connected to ground gnd _ ptat of the current stabilizing circuit. Eighteen M transistors₁₈Is connected with a seventeen M transistor₁₇The grid and the drain of the transistor are connected with nineteen M₁₉And the source of the current stabilizing circuit is connected to ground gnd _ ptat of the current stabilizing circuit. Nineteen M transistors₁₉Is connected with the drain electrode and the source electrode is connected with a power supply V of the current stabilizing circuit_{cc_ptat}. Transistor twenty M₂₀Is connected with a nineteen M transistors₁₉The source of the grid is connected with a power supply V of the current stabilizing circuit_{cc_ptat}And the drain is connected with the feedback node FB. Eighteen M transistors₁₈And transistor seventeen M₁₇Form a first current mirror structure, a transistor twenty M₂₀And transistor nineteen M₁₉A second current mirror structure is formed, and a negative temperature coefficient current source I_ctThe two current mirror structures obtain an adjusting current I which is inversely proportional to absolute temperature_ctatThe regulated current I_ctatPower supply V of slave current stabilizing circuit_{cc_ptat}Is pulled down to the feedback node FB.

The current stabilizing circuit shown in fig. 9 has a current I inversely proportional to the temperature when the temperature decreases_ctatIncrease, assuming reference current I_rampAnd a compensation current I_compAre not changed, then the sampling current I of the power output stage_senseWith a consequent reduction, which indicates the flow of power in the power output stageThe current of the transistor is reduced, so that the output power V of the radio frequency power amplifier_outAnd decreases. At the same time, the feedback voltage V of the feedback node FB_fbAdjusting tube M of low dropout regulator in step-up, voltage current conversion circuit_AGate voltage V of_g(i.e., the output voltage of the operational amplifier OP) is increased, and the output voltage V of the low dropout regulator is decreased_ldo. Therefore, the power supply voltage of the preamplifier is reduced, the gain of the preamplifier is reduced, and the stability of the radio frequency power amplifier is improved.

Please refer to fig. 10, which is a schematic diagram illustrating isolation of power supplies of modules of the high-stability rf power amplifier according to the present application. As shown in fig. 1, the high-stability rf power amplifier of the present application includes five modules, which are a preamplifier, a power output stage, a voltage-to-current conversion circuit, a power supply voltage compensation circuit and a current stabilization circuit, and their respective power supplies are V_ldo、V_{cc_ps}、V_{cc_vi}、V_{cc_comp}And V_{cc_ptat}. The modules have large high-frequency interference and coupling, so that positive feedback is easy to generate, and the stability problem is caused. Therefore, the present application inserts isolation circuits between the power supplies of the modules, and one isolation circuit is indicated by a dashed line in fig. 10 to improve the stability of the rf power amplifier.

Please refer to fig. 11, which is a schematic diagram illustrating isolation between the ground of each module of the high stability rf power amplifier provided in the present application. As shown in fig. 1, the high-stability rf power amplifier of the present application includes five modules, which are a preamplifier, a power output stage, a voltage-to-current conversion circuit, a supply voltage compensation circuit, and a current stabilization circuit, and their respective ground is gnd _ pre, gnd _ ps, gnd _ vi, gnd _ comp, and gnd _ ptat. The modules have large high-frequency interference and coupling, so that positive feedback is easy to generate, and the stability problem is caused. Therefore, the present application inserts two isolation circuits between the grounds of the modules, and one isolation circuit is shown by a dashed line in fig. 11 to improve the stability of the rf power amplifier.

Please refer to fig. 12a, which shows a first embodiment of the isolation circuit in fig. 10 and 11. The isolation circuit of the embodiment is an RLC parallel circuit, and the isolation resistor Ri, the isolation inductor Li and the isolation capacitor Ci are connected in parallel between two objects needing isolation, namely ISO1 and ISO 2.

Please refer to fig. 12b, which shows a second embodiment of the isolation circuit of fig. 10 and 11. The isolation circuit of the embodiment is an RC and LC filter circuit, and the isolation resistor Ri and the isolation inductor Li are connected in parallel between two objects needing isolation, namely ISO1 and ISO 2. The isolation capacitor Ci connects one object ISO2 that needs to be isolated and the ground Clean gnd alone.

Please refer to fig. 12c, which shows a third embodiment of the isolation circuit in fig. 10 and 11. The isolation circuit of the embodiment is of a head-to-tail diode structure, the first isolation diode Di1 is connected between two objects needing isolation in a reverse direction, namely ISO1 and ISO2, and the second isolation diode Di2 is connected between two objects needing isolation in a forward direction, namely ISO1 and ISO 2.

In other embodiments, the isolation circuit may be selected to be an open (open) or short circuit, as desired.

The above are merely preferred embodiments of the present application and are not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.