阅读说明：本技术 一种输出电压调节电路及其恒压输出系统 (Output voltage regulating circuit and constant voltage output system thereof ) 是由 闫志光 王彬 于 2021-09-01 设计创作，主要内容包括：本申请提供一种输出电压调节电路及其恒压输出系统,该输出电压调节单路包括：补偿电路和误差放大电路,补偿电路包括负载电流补偿单元、输入电压补偿单元、补偿电阻R1以及稳流单元,本方案利用负载电流补偿单元消除或减小负载电流的变化对输出电压的影响；并且利用输入电压补偿单元消除或减小输入电压的变化对输出电压的影响,从而实现电源输出电压的恒定输出。(The application provides an output voltage regulating circuit and constant voltage output system thereof, this output voltage regulation single-circuit includes: the compensation circuit comprises a load current compensation unit, an input voltage compensation unit, a compensation resistor R1 and a current stabilization unit, and the scheme utilizes the load current compensation unit to eliminate or reduce the influence of the change of load current on output voltage; and the influence of the change of the input voltage on the output voltage is eliminated or reduced by using the input voltage compensation unit, so that the constant output of the output voltage of the power supply is realized.)

1. An output voltage regulation circuit, comprising: the compensation circuit (10) and the error amplification circuit (20), wherein the compensation circuit (10) comprises a load current compensation unit (101), a compensation resistor R1 and a current stabilization unit (102);

the load current compensation unit (101) is used for generating a load compensation current according to the error signal output by the error amplification circuit (20), and generating a load compensation voltage according to the load compensation current, a compensation resistor R1 and a current stabilization unit (102) and transmitting the load compensation voltage to a non-inverting input end of the error amplification circuit (20);

the error amplifying circuit (20) is used for outputting corresponding error signals according to output voltage and the load compensation voltage, and the error signals are used for correspondingly adjusting the output voltage of the modulation circuit (30) so as to realize constant voltage output.

2. The output voltage regulating circuit according to claim 1, wherein an input terminal of the load current compensating unit (101) is connected to an output terminal of the error amplifying circuit (20), an output terminal of the load current compensating unit (101) is connected to the current stabilizing unit (102) in series through a compensating resistor R1, an output terminal of the load current compensating unit (101) is connected to a non-inverting input terminal of the error amplifying circuit (20), an inverting input terminal of the error amplifying circuit (20) is used for sampling the output voltage, and an output terminal of the error amplifying circuit (20) is used for being connected to the modulating circuit (30).

3. The output voltage regulating circuit according to claim 2, wherein the load current compensation unit (101) comprises a current compensation error amplifier (1011), a compensation resistor R2, a current compensation controllable switch tube (1012) and a current compensation current mirror (1013);

the non-inverting input end of the current compensation error amplifier (1011) is connected with the output end of the error amplifying circuit (20), the inverting input end of the current compensation error amplifier (1011) is grounded through a compensation resistor R2, the output end of the current compensation error amplifier (1011) is connected with the control end of the current compensation controllable switch tube (1012), the first end of the current compensation controllable switch tube (1012) is connected with the inverting input end of the current compensation error amplifier (1011), and the second end of the current compensation controllable switch tube (1012) is connected with a compensation resistor R1 through a current compensation current mirror (1013);

the current compensation error amplifier (1011) is used for clamping the voltage of the error signal to the first end of the current compensation controllable switch tube (1012) so as to form a compensation current on the branch of the compensation resistor R2 and the current compensation controllable switch tube (1012) and output the compensation current to the current compensation current mirror (1013);

the current compensation current mirror (1013) is configured to generate the load compensation current according to a corresponding current mirror proportion and the compensation current.

4. The output voltage regulating circuit according to claim 2, further comprising a modulation circuit (30), wherein an input terminal of the modulation circuit (30) is connected to an output terminal of the error amplifying circuit (20), and an output terminal of the modulation circuit (30) is configured to be connected to a controllable switching transistor (Q1);

the modulation circuit (30) is used for outputting a corresponding modulation signal according to the error signal so as to adjust the duty ratio of the controllable switch tube (Q1), so that the output voltage is correspondingly adjusted to realize constant voltage output, wherein the duty ratio of the controllable switch tube (Q1) is in positive correlation with the modulation signal.

5. The output voltage regulation circuit of any one of claims 1-4 wherein the error signal, the load compensation current, the load compensation voltage, and the load current are all positively correlated, and wherein the error signal and the output voltage are positively correlated.

6. The output voltage regulation circuit of claim 1, wherein the compensation circuit (10) further comprises an input voltage compensation unit (110);

the input voltage compensation unit (110) is used for generating an input voltage compensation current according to an input voltage, generating an input compensation voltage according to the input voltage compensation current, the compensation resistor R1 and the current stabilization unit (102), and transmitting the input compensation voltage to a non-inverting input end of the error amplification circuit (20), wherein the input voltage is a sampling voltage corresponding to a bus voltage;

the error amplifying circuit (20) is further configured to output a corresponding error signal according to the load compensation voltage, the input compensation voltage, and the output voltage.

7. An output voltage regulation circuit, comprising: the compensation circuit (10) comprises an input voltage compensation unit (110), a compensation resistor R5 and a current stabilization unit (102), and the error amplification circuit (20);

the input voltage compensation unit (110) is used for generating an input voltage compensation current according to an input voltage, generating an input compensation voltage according to the input voltage compensation current and a compensation resistor R5, and transmitting the input compensation voltage to a non-inverting input end of the error amplification circuit (20), wherein the input voltage is a sampling voltage corresponding to a bus voltage;

and the error amplifying circuit (20) is used for outputting corresponding error signals according to the output voltage and the input compensation voltage, and the error signals are used for correspondingly adjusting the output voltage controlled by the modulation circuit (30) so as to realize constant voltage output.

8. The output voltage regulating circuit according to claim 7, wherein an input terminal of the input voltage compensating unit (110) is configured to receive the input voltage, an output terminal of the input voltage compensating unit (110) is connected in series with the current stabilizing unit (102) through a compensating resistor R5, an output terminal of the input voltage compensating unit (110) is connected to a non-inverting input terminal of the error amplifying circuit (20), an inverting input terminal of the error amplifying circuit (20) is configured to sample the output voltage, and an output terminal of the error amplifying circuit (20) is configured to be connected to the modulating circuit (30).

9. The output voltage regulation circuit of claim 8, wherein the input voltage compensation unit (110) comprises: the voltage compensation circuit comprises a voltage compensation error amplifier (1102), a compensation resistor R6, a voltage compensation controllable switch tube (1103) and a voltage compensation current mirror (1104);

the non-inverting input end of the voltage compensation error amplifier (1102) is used for receiving the input voltage, the inverting input end of the voltage compensation error amplifier (1102) is grounded through a compensation resistor R6, the output end of the voltage compensation error amplifier (1102) is connected with the control end of the voltage compensation controllable switch tube (1103), the first end of the voltage compensation controllable switch tube (1103) is grounded through a compensation resistor R6, and the second end of the voltage compensation controllable switch tube (1103) is connected with a compensation resistor R5 through the voltage compensation current mirror (1104;

the voltage compensation error amplifier (1102) is used for clamping the input voltage to a first end of the voltage compensation controllable switch tube (1103) so as to form a compensation current on a branch of the compensation resistor R6 and the voltage compensation controllable switch tube (1103) and output the compensation current to the voltage compensation current mirror (1104);

the voltage compensation current mirror (1104) is configured to generate the input voltage compensation current according to the corresponding current mirror proportion and the compensation current.

10. A constant pressure output system, comprising: a rectifying module (1), a constant voltage control chip (2) and a buck conversion module (3), the constant voltage control chip (2) comprising the output voltage regulating circuit of any one of claims 1-9;

the input of rectifier module (1) is used for receiving the alternating current, the output of rectifier module (1) with constant voltage control chip (2) are coupled, be provided with a controllable switch pipe (Q1) in constant voltage control chip (2), the output of rectifier module (1) passes through controllable switch pipe (Q1) with it is coupled to step-down transform module (3), the output of step-down transform module (3) with the inverting input of error amplification circuit (20) is connected, the output of error amplification circuit (20) with controllable switch pipe (Q1) are connected to adjust output voltage.

Technical Field

The application relates to the technical field of power supply constant voltage output, in particular to an output voltage regulating circuit and a constant voltage output system thereof.

Background

The output voltage of the conventional power supply is influenced by the input voltage (i.e. the bus voltage), and besides the input voltage, the output voltage value is also influenced by the load current change.

Disclosure of Invention

An object of the embodiments of the present application is to provide an output voltage regulating circuit and a constant voltage output system thereof, so as to eliminate or reduce the influence of the change of a bus voltage or the change of a load current on an output voltage, thereby realizing the constant voltage output of a power supply.

In a first aspect, the present invention provides an output voltage regulating circuit, comprising: the compensation circuit comprises a load current compensation unit, a compensation resistor R1 and a current stabilization unit; the load current compensation unit is used for generating load compensation current according to an error signal output by the error amplification circuit, generating load compensation voltage according to the load compensation current, the compensation resistor R1 and the current stabilization unit, and transmitting the load compensation voltage to a positive phase input end of the error amplification circuit; the error amplifying circuit is used for outputting corresponding error signals according to the output voltage and the load compensation voltage, and the error signals are used for correspondingly adjusting the output voltage controlled by the modulating circuit so as to realize constant voltage output.

In the output voltage regulating circuit of the above design, since the change of the error signal output by the error amplifying circuit can reflect the change of the load current and show a positive correlation, in the first aspect, the load current compensating unit is adopted to generate a load compensating current with a positive correlation according to the error signal output by the error amplifying circuit, and then generate a load compensating voltage with a positive correlation based on the load compensating current to be output to the positive input terminal of the error amplifying circuit, so that the error amplifying circuit outputs the error signal with a positive correlation change with the load compensating voltage, and further the output voltage regulated based on the error signal also shows a positive correlation change with the load compensating voltage, thus compensating the inverse correlation change originally shown by the output voltage and the load current change, keeping the output voltage basically unchanged, and eliminating or reducing the influence of the change of the load current on the output voltage, thereby realizing the constant voltage output of the power supply.

In an optional implementation manner of the first aspect, an input end of the load current compensation unit is connected to an output end of the error amplification circuit, an output end of the load current compensation unit is connected in series with the current stabilization unit through a compensation resistor R1, an output end of the load current compensation unit is connected to a non-inverting input end of the error amplification circuit, an inverting input end of the error amplification circuit is used for sampling the output voltage, and an output end of the error amplification circuit is used for being connected to the modulation circuit.

In an optional implementation manner of the first aspect, the load current compensation unit includes a current compensation error amplifier, a compensation resistor R2, a current compensation controllable switch tube, and a current compensation current mirror; the non-inverting input end of the current compensation error amplifier is connected with the output end of the error amplifying circuit, the inverting input end of the current compensation error amplifier is grounded through a compensation resistor R2, the output end of the current compensation error amplifier is connected with the control end of the current compensation controllable switch tube, the first end of the current compensation controllable switch tube is connected with the inverting input end of the current compensation error amplifier, and the second end of the current compensation controllable switch tube is connected with a compensation resistor R1 through the current compensation current mirror; the current compensation error amplifier is used for clamping the voltage of the error signal to the first end of the current compensation controllable switch tube so as to form a compensation current on the compensation resistor R2 and the current compensation controllable switch tube branch and output the compensation current to the current compensation current mirror; the current compensation current mirror is used for generating the load compensation current according to the corresponding current mirror proportion and the compensation current.

In an optional implementation manner of the first aspect, the current stabilization unit includes a current stabilization error amplifier, a current stabilization resistor R3, and a current stabilization controllable switching tube; the current-stabilizing control circuit comprises a current-stabilizing error amplifier, a current-stabilizing resistor R3, a current-stabilizing resistor R1, a compensation resistor R1 and a current-stabilizing controllable switch tube, wherein the positive phase input end of the current-stabilizing error amplifier is used for receiving a preset reference voltage, the negative phase input end of the current-stabilizing error amplifier is grounded through the current-stabilizing resistor R3, the output end of the current-stabilizing error amplifier is connected with the control end of the current-stabilizing controllable switch tube, the first end of the current-stabilizing controllable switch tube is respectively connected with the negative phase input end of the current-stabilizing error amplifier and the compensation resistor R1, and the second end of the current-stabilizing controllable switch tube is used for being connected with a power supply.

In an optional implementation of the first aspect, the output voltage regulation circuit further comprises a voltage sampling circuit, and an inverting input of the error amplification circuit is coupled to the voltage sampling circuit to sample the output voltage.

In an optional implementation manner of the first aspect, the output voltage regulating circuit further includes a modulation circuit, an input end of the modulation circuit is connected to an output end of the error amplifying circuit, and an output end of the modulation circuit is used for being connected to the controllable switch tube; the modulation circuit is used for outputting a corresponding modulation signal according to the error signal so as to adjust the duty ratio of the controllable switch tube, so that the output voltage is correspondingly adjusted to realize constant voltage output, wherein the duty ratio of the controllable switch tube is positively correlated with the modulation signal.

In an alternative embodiment of the first aspect, the error signal, the load compensation current, the load compensation voltage and the load current are all positively correlated.

In an alternative embodiment of the first aspect, the error signal and the output voltage are positively correlated.

In an optional implementation of the first aspect, the compensation circuit further comprises an input voltage compensation unit; the input voltage compensation unit is used for generating an input voltage compensation current according to an input voltage, generating an input compensation voltage according to the input voltage compensation current, the compensation resistor R1 and the current stabilization unit, and transmitting the input compensation voltage to a positive phase input end of the error amplification circuit, wherein the input voltage is a sampling voltage corresponding to a bus voltage; the error amplifying circuit is further configured to output a corresponding error signal according to the load compensation voltage, the input compensation voltage, and the output voltage.

In the embodiment designed above, based on the load current compensation unit generating a positively correlated load compensation voltage based on the load compensation current, a positively correlated input voltage compensation current is generated from the input voltage by the input voltage compensation unit, a positively correlated input compensation voltage is generated based on the input voltage compensation current, and then the load compensation voltage and the input compensation voltage are output to the positive input terminal of the error amplification circuit, so that the error amplification circuit outputs an error signal that varies in positive correlation with both the load compensation voltage and the input compensation voltage, and further the output voltage adjusted based on the error signal also varies in positive correlation with both the load compensation voltage and the input compensation voltage, thus compensating both the variation in which the output voltage originally exhibits inverse correlation with the variation in the input voltage and the inverse correlation variation in which the output voltage exhibits inverse correlation with the variation in the load current, the output voltage is basically kept unchanged, so that the influence of the change of the input voltage and the load current on the output voltage is eliminated or reduced, and the constant voltage output of the power supply is realized.

In a second aspect, the present invention provides an output voltage regulating circuit comprising: the compensation circuit comprises an input voltage compensation unit, a compensation resistor R5 and a current stabilization unit; the input voltage compensation unit is used for generating an input voltage compensation current according to an input voltage, generating an input compensation voltage according to the input voltage compensation current and a compensation resistor R5, and transmitting the input compensation voltage to a positive phase input end of the error amplification circuit, wherein the input voltage is a sampling voltage corresponding to a bus voltage; the error amplifying circuit is used for outputting corresponding error signals according to the output voltage and the input compensation voltage, and the error signals are used for correspondingly adjusting the output voltage controlled by the modulating circuit so as to realize constant voltage output.

In the output voltage regulating circuit of the above design, the input voltage compensation unit generates a positively correlated input voltage compensation current according to the input voltage, and then generates a positively correlated input compensation voltage based on the input voltage compensation current to be output to the positive input terminal of the error amplifying circuit, so that the error amplifying circuit outputs an error signal that changes positively in correlation with the input compensation voltage, and further the output voltage regulated based on the error signal also changes positively in correlation with the input compensation voltage, thereby compensating for the inversely correlated change of the original output voltage due to the change of the input voltage, and keeping the output voltage substantially unchanged, thereby eliminating or reducing the influence of the change of the input voltage on the output voltage, and further realizing the constant voltage output of the power supply.

In an optional implementation manner of the second aspect, an input end of the input voltage compensation unit is configured to receive the input voltage, an output end of the input voltage compensation unit is connected in series with the current stabilization unit through a compensation resistor R5, an output end of the input voltage compensation unit is connected to a non-inverting input end of the error amplification circuit, an inverting input end of the error amplification circuit is configured to sample the output voltage, and an output end of the error amplification circuit is configured to be connected to a modulation circuit.

In an optional embodiment of the second aspect, the input voltage compensation unit comprises: the voltage compensation error amplifier, the compensation resistor R6, the voltage compensation controllable switch tube and the voltage compensation current mirror; the positive phase input end of the voltage compensation error amplifier is used for receiving the input voltage, the negative phase input end of the voltage compensation error amplifier is grounded through a compensation resistor R6, the output end of the voltage compensation error amplifier is connected with the control end of the voltage compensation controllable switch tube, the first end of the voltage compensation controllable switch tube is grounded through a compensation resistor R6, and the second end of the voltage compensation controllable switch tube is connected with a compensation resistor R5 through the voltage compensation current mirror; the voltage compensation error amplifier is used for clamping the input voltage to a first end of the voltage compensation controllable switch tube so as to form a compensation current on the compensation resistor R6 and the voltage compensation controllable switch tube branch and output the compensation current to the voltage compensation current mirror; and the voltage compensation current mirror is used for forming the input voltage compensation current according to the corresponding current mirror proportion and the compensation current.

In a third aspect, the present invention provides a constant voltage output system, including a rectification module, a constant voltage control chip and a buck conversion module, where the constant voltage control chip includes the output voltage regulating circuit of any one of the first aspect or the second aspect; the input end of the rectification module is used for receiving alternating current, the output end of the rectification module is coupled with the constant voltage control chip, a controllable switch tube is arranged in the constant voltage control chip, the output end of the rectification module is coupled with the voltage reduction conversion module through the controllable switch tube, the output end of the voltage reduction conversion module is connected with the reverse phase input end of the error amplification circuit, and the output end of the error amplification circuit is connected with the controllable switch tube so as to adjust output voltage.

In the constant voltage output system designed in the third aspect, because the output voltage regulating circuit in any one of the embodiments of the first aspect or the second aspect is included in the constant voltage control chip of the designed constant voltage output system, the designed constant voltage output system can eliminate or reduce the influence of the load current and/or the input voltage on the output voltage, and realize more accurate constant voltage output of the power supply.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

FIG. 1 is a first block diagram of an output voltage regulator circuit according to a first embodiment of the present application;

FIG. 2 is a second block diagram of an output voltage regulator circuit according to a first embodiment of the present application;

FIG. 3 is a third schematic diagram of an output voltage regulator circuit according to the first embodiment of the present application;

FIG. 4 is a fourth block diagram of an output voltage regulator circuit according to the first embodiment of the present application;

FIG. 5 is a first block diagram of an output voltage regulator circuit according to a second embodiment of the present application;

FIG. 6 is a second block diagram of an output voltage regulator circuit according to a second embodiment of the present application;

FIG. 7 is a third schematic diagram of an output voltage regulator circuit according to a second embodiment of the present application;

FIG. 8 is a fourth block diagram of an output voltage regulator circuit according to a second embodiment of the present application;

FIG. 9 is a first block diagram of an output voltage regulator circuit according to a third embodiment of the present application;

FIG. 10 is a second block diagram of an output voltage regulator circuit according to a third embodiment of the present application;

fig. 11 is a schematic structural diagram of a constant voltage output system according to a fourth embodiment of the present application.

Icon: 1-a rectification module; 2-constant voltage control chip; 3-a step-down conversion module; 4-an output voltage regulation circuit; 10-a compensation circuit; 101-a load current compensation unit; 1011-current compensated error amplifier; 1012-current compensation controllable switch tube; 1013-current compensation current mirror; 102-a flow stabilizing unit; 1021-a current-stabilizing error amplifier; 1022-current-stabilizing controllable switching tube; 110-input voltage compensation unit; 1101-an input voltage sampling subunit; 1102-a voltage compensation error amplifier; 1103-voltage compensation controllable switching tube; 1104-voltage compensated current mirror; 20-an error amplification circuit; 30-a modulation circuit; 40-a voltage sampling circuit; q1-controllable switch tube.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

First embodiment

The present embodiment provides an output voltage regulating circuit, which is used to eliminate or reduce the influence of the change of the load current on the output voltage, thereby realizing the stable output of the constant voltage of the power supply.

As shown in fig. 1, the output voltage regulating circuit includes a compensation circuit 10 and an error amplifying circuit 20, and the compensation circuit 10 includes a load current compensation unit 101, a compensation resistor R1, and a current stabilization unit 102.

The input end of the load current compensation unit 101 is connected with the output end of the error amplification circuit 20, the output end of the load current compensation unit 101 is connected in series with the current stabilization unit 102 through a compensation resistor R1, the output end of the load current compensation unit 101 is connected with the positive input end of the error amplification circuit 20, the negative input end of the error amplification circuit 20 is used for sampling output voltage, and the output voltage can be the output voltage of a power supply chip or the voltage output to a power supply load; the output of the error amplifier circuit 20 is connected to the modulation circuit 30. The error amplifier circuit 20 may be an error amplifier as shown in fig. 1, or may be another type of circuit having an error amplifier.

In the output voltage regulating circuit with the above design, the change of the error signal output by the error amplifying circuit 20 may reflect the change of the load current, for example, when the load current is smaller, the error signal Veao of the error amplifying circuit 20 is smaller; when the load current is large, the error signal Veao output by the error amplifying circuit 20 is large, and therefore, the change of the error signal Veao of the error amplifying circuit 20 is collected to represent the change of the load current in the embodiment, and the output voltage is adjusted.

When the load current compensation circuit is applied, the load current compensation unit 101 collects the error signal Veao and generates a load compensation current I1 according to the error signal Veao, and generates a load compensation voltage Vcomp1 according to the load compensation current I1, the compensation resistor R1 and the current stabilizing unit 102 and transmits the load compensation voltage Vcomp to the non-inverting input terminal of the error amplification circuit 20, because the load compensation current I1 is in positive correlation with the error signal Veao, if the load current increases, the error signal Veao output by the error amplification circuit 20 increases, then the load compensation current I1 increases, so that the load compensation voltage Vcomp1 transmitted to the non-inverting input terminal of the error amplification circuit 20 also increases.

The inverting input terminal of the error amplifying circuit 20 samples the output voltage, the output voltage of the power supply is reduced due to the increase of the load current, and meanwhile, the load compensation voltage Vcomp1 received by the non-inverting input terminal of the error amplifying circuit 20 is increased, so that the error signal Veao output by the error amplifying circuit 20 is further increased on the basis of the original increase, the further increased error signal Veao is output to the modulating circuit 30, the modulating circuit 30 adjusts the output voltage according to the further increased error signal Veao, the output voltage reduced due to the increase of the load current is increased, and further under the condition that the load current is increased, the output voltage is basically kept unchanged, the influence of the change of the load current on the output voltage is eliminated or reduced, and further, the constant voltage output of the power supply is realized.

In an alternative embodiment of this embodiment, as shown in fig. 2, the load current compensation unit 101 includes a current compensation error amplifier 1011, a compensation resistor R2, a current compensation controllable switch tube 1012, and a current compensation current mirror 1013.

The positive phase input end of the current compensation error amplifier 1011 is connected to the output end of the error amplifying circuit 20, the negative phase input end of the current compensation error amplifier 1011 is grounded through a compensation resistor R2, the output end of the current compensation error amplifier 1011 is connected to the control end of the current compensation controllable switch tube 1012, the first end of the current compensation controllable switch tube 1012 is connected to the negative phase input end of the current compensation error amplifier 1011, and the second end of the current compensation controllable switch tube 1012 is connected to the compensation resistor R1 through a current compensation current mirror 1013. The current compensation controllable switch tube 1012 may be a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) tube, on the basis of which a first end of the current compensation controllable switch tube 1012 is a source, a second end of the current compensation controllable switch tube 1012 is a drain, a control end of the current compensation controllable switch tube 1012 is a Gate, and the current compensation controllable switch tube 1012 may be a controllable switch tube of other forms besides the MOSFET tube, such as an Insulated Gate Bipolar Transistor (IGBT) and the like.

In the load current compensation unit 101 with the above design, the error signal Veao output by the error amplifying circuit 20 is transmitted to the current compensation error amplifier 1011, so that the compensation resistor R2, the current compensation controllable switch tube 1012 and the power supply VDD form a compensation current I0, where I0 is Veao/R2; the compensation current I0 forms the aforementioned load compensation current I1 through the current compensation current mirror 1013, wherein, assuming that the proportion of the current compensation current mirror 1013 is K1, I1 is I0 × K1.

Based on the foregoing example, if the load current increases, the error signal Veao increases, I0 increases, so that the load compensation current I1 also increases, the load compensation voltage Vcomp1 increases, and the output voltage is increased, so that the output voltage is kept unchanged when the load current increases, thereby eliminating or reducing the influence of the change of the load current on the output voltage, and further realizing the constant voltage output of the power supply. It should be noted here that, in order to keep the output voltage constant, the proportion of the current mirror 1013 and/or the size of the compensation resistor R2 may be adjusted to further adjust the size of the compensation voltage to keep the output voltage constant.

In an alternative embodiment of this embodiment, as shown in fig. 2, the current stabilizing unit 102 includes a current stabilizing error amplifier 1021, a current stabilizing resistor R3, and a current stabilizing controllable switching tube 1022.

The positive phase input end of the current stabilization error amplifier 1021 is used for receiving a preset reference voltage Vref1, the negative phase input end of the current stabilization error amplifier 1021 is grounded through a current stabilization resistor R3, the output end of the current stabilization error amplifier 1021 is connected with the control end of a current stabilization controllable switch tube 1022, the first end of the current stabilization controllable switch tube 1022 is respectively connected with the negative phase input end of the current stabilization error amplifier 1021 and a compensation resistor R1, and the second end of the current stabilization controllable switch tube 1022 is used for being connected with a power supply VDD.

The current stabilizing unit 102, the current stabilizing resistor R3, the current stabilizing controllable switch tube 1022 and the power supply VDD branch circuit form the current stabilizing I3, and the reference voltage at the positive phase input end of the current stabilizing error amplifier 1021 is unchanged, so that the current stabilizing I3 is continuously unchanged, the current generated by the current stabilizing unit 102 is continuously unchanged, the change of the load compensation voltage Vcomp1 formed by the compensation resistor R1 can accurately reflect the change of the load compensation current I1, the formed load compensation voltage Vcomp1 is more accurate, and the adjustment of the output voltage is more accurate.

In an alternative embodiment of the present embodiment, as shown in fig. 3, the compensation circuit 10 may further include a compensation resistor R4, and the compensation resistor R4 is connected in series between the load current compensation unit 101 and the compensation resistor R1.

In the embodiment of the above design, the load compensation voltage Vcomp1 can be formed not only by the compensation resistor R1 and the load compensation current I1, but also by the compensation resistor R1 and the compensation resistor R4 being superimposed. In this embodiment, the load compensation voltage Vcomp1 is I1 (R1+ R4). Here, it should be noted that, in addition to the compensation resistor R4, a plurality of compensation resistors may be used.

In an alternative implementation manner of this embodiment, as shown in fig. 4, the output voltage regulating circuit may further include a modulation circuit 30, an input terminal of the modulation circuit 30 is connected to the output terminal of the error amplifying circuit 20, and an output terminal of the modulation circuit 30 is configured to be connected to the controllable switching transistor Q1.

As an embodiment, the modulation circuit 30 may be a comparator, a first input end of the comparator is connected to the output end of the error amplifying circuit 20 to receive the error signal Veao output by the error amplifying circuit 20, a second input end of the comparator is configured to receive the sampling voltage VL of the peak current, a third end of the comparator is configured to receive the slope compensation voltage RAW (preset), and the comparator outputs a modulation signal d based on the error signal Veao, the sampling voltage VL and the slope compensation voltage RAW, and the modulation signal d is positively correlated with the error signal Veao. For example, when the load current increases, the error signal Veao increases, so that the modulation signal d increases, the increased modulation signal d increases the duty ratio of the controllable switching tube Q1, and further the controllable switch Q1 controls the output voltage to increase, so that the output voltage decreased due to the increase of the load current increases, and further the output voltage keeps constant.

In an alternative implementation manner of this embodiment, as shown in fig. 4, the output voltage regulating circuit may further include a voltage sampling circuit 40, where the voltage sampling circuit 40 is coupled to the inverting input terminal of the error amplifying circuit 20, so that the error amplifying circuit 20 samples the output voltage through the voltage sampling circuit 40.

As a possible implementation, the voltage sampling circuit 40 may include a sampling resistor R10 and a sampling resistor R11, a first end of the sampling resistor R10 is configured to receive the output voltage, a second end of the sampling resistor R10 is connected to the ground through the sampling resistor R11, and a second end of the sampling resistor R10 is connected to the inverting input terminal of the error amplifying circuit, so that the error amplifying circuit 20 samples the output voltage through the voltage sampling circuit 40.

On the basis of the above, the voltage sampled at the inverting input terminal of the error amplifying circuit 20 may be a divided voltage Vfb of the output voltage Vout, and the divided voltage Vfb exhibits a synchronous variation with the output voltage Vout.

Second embodiment

The embodiment provides an output voltage regulating circuit which can eliminate or reduce the influence of the change of input voltage on output voltage so as to realize the constant voltage output of a power supply.

As shown in fig. 5, the output voltage regulating circuit includes a compensation circuit 10 and an error amplifying circuit 20, in this embodiment, the compensation circuit 10 includes an input voltage compensation unit 110, a compensation resistor R5, and a current stabilizing unit 102, an input end of the input voltage compensation unit 110 is used for being connected to an input voltage, which is a sampling voltage corresponding to a bus voltage.

The output end of the input voltage compensation unit 110 is connected in series with the current stabilization unit 102 through a compensation resistor R5, the output end of the input voltage compensation unit 110 is connected with the non-inverting input end of the error amplification circuit 20, the inverting input end of the error amplification circuit 20 is used for sampling the output voltage, and the output end of the error amplification circuit 20 is used for being connected with the modulation circuit 30.

In the output voltage adjusting circuit designed as described above, the input voltage Vm is collected by the input voltage compensation unit 110, the input voltage compensation unit 110 generates the input voltage compensation current I2 according to the input voltage, the input voltage compensation current I2 and the compensation resistor R5 generate the input compensation voltage Vcomp2 and transmit the input compensation voltage Vcomp2 to the non-inverting input terminal of the error amplifying circuit 20, and since the input voltage Vm is positively correlated with the input voltage compensation current I2, if the input voltage Vm increases, the input voltage compensation current I2 increases, so that the input compensation voltage Vcomp2 also increases.

The inverting input terminal of the error amplifying circuit 20 samples the output voltage of the power supply, and the output voltage Vout of the power supply decreases as the input voltage Vm increases; the input compensation voltage Vcomp2 received by the non-inverting input terminal of the error amplifying circuit 20 is increased, which further increases the error signal Veao output by the error amplifying circuit 20 on the basis of the original increase, and the further increased error signal Veao is output to the modulation circuit 30, so that the modulation circuit 30 adjusts the output voltage according to the further increased error signal Veao, so that the originally decreased output voltage is increased, and further, the output voltage is basically kept unchanged under the condition that the input voltage is increased; when the input voltage is reduced, the principle is similar to the principle, and details are not repeated herein, and the influence of the change of the input voltage on the output voltage can be eliminated or reduced through the designed output voltage regulating circuit, so that the constant voltage output of the power supply is realized.

In an alternative implementation manner of this embodiment, as shown in fig. 6, the input voltage compensation unit 110 includes an input voltage sampling subunit 1101, a voltage compensation error amplifier 1102, a compensation resistor R6, a voltage compensation controllable switch tube 1103, and a voltage compensation current mirror 1104.

The input end of the input voltage sampling sub-unit 1101 is configured to receive an input voltage Vm, the non-inverting input end of the voltage compensation error amplifier 1102 is coupled to the input voltage sampling sub-unit 1101, the inverting input end of the voltage compensation error amplifier 1102 is grounded through a compensation resistor R6, the output end of the voltage compensation error amplifier 1102 is connected to the control end of the voltage compensation controllable switch transistor 1103, the first end of the voltage compensation controllable switch transistor 1103 is grounded through a compensation resistor R6, and the second end of the voltage compensation controllable switch transistor 1103 is connected to a compensation resistor R5 through a voltage compensation current mirror 1104. The voltage compensation controllable switch Transistor 1103 may be an MOS Transistor, and on this basis, the first end of the voltage compensation controllable switch Transistor 1103 is a source, the second end of the voltage compensation controllable switch Transistor 1103 is a drain, the control end of the voltage compensation controllable switch Transistor 1103 is a Gate, and the voltage compensation controllable switch Transistor 1103 may be a controllable switch Transistor of other forms, such as an Insulated Gate Bipolar Transistor (IGBT) besides the MOS Transistor.

In the input voltage compensation unit 110 designed above, the non-inverting input terminal of the voltage compensation error amplifier 1102 receives the input voltage Vm sampled by the input voltage sampling sub-unit 1101, and since the inverting input terminal of the voltage compensation error amplifier 1102 is connected to the compensation resistor R6 and the voltage compensation controllable switch 1103 branch, the compensation current I3 is formed on the compensation resistor R6 and the voltage compensation controllable switch 1103 branch, and the compensation current I3 forms the input voltage compensation current I2 through the voltage compensation current mirror 1104, and further forms the input compensation voltage Vcomp2 with the compensation resistor R5 and transmits the input compensation voltage Vcomp2 to the error amplification circuit 20.

In the input voltage compensation unit 110 designed as described above, when the input voltage Vm increases, if I3 is Vm/R6, the formed compensation current I3 increases, and if the current mirror ratio of the voltage compensation current mirror 1104 is K2, if I2 is K2I 3, the formed input voltage compensation current I2 also increases; since Vcomp2 is I2 × R2, the formed input compensation voltage Vcomp2 is also increased, and the originally decreased output voltage is increased according to the foregoing principle, so that the output voltage is basically kept unchanged when the input voltage is increased.

As a possible implementation, as shown in fig. 7, the input voltage sampling sub-unit 1101 may include a sampling resistor R7 and a sampling resistor R8, a first end of the sampling resistor R7 is configured to receive the input voltage Vm, a second end of the sampling resistor R7 is connected to the ground through the sampling resistor R8, and a non-inverting input terminal of the voltage compensation error amplifier 1102 is connected to a second end of the sampling resistor R7, so that the divided voltage Vx of the input voltage Vm sampled by the input voltage sampling sub-unit 1101 is input to the non-inverting input terminal of the voltage compensation error amplifier 1102. On this basis, the aforementioned compensation current I3 is now equal to Vx/R6.

In an optional implementation manner of this embodiment, as shown in fig. 8, the output voltage regulating circuit of this embodiment may also include a modulation circuit 30 and a voltage sampling circuit 40, where the modulation circuit 30 and the voltage sampling circuit 40 are the same as those described in the first embodiment, and are not described herein again.

Third embodiment

The present embodiment designs an output voltage regulating circuit, which is used to eliminate or reduce the influence of the load current and the change of the input voltage on the output voltage, thereby realizing the constant voltage output of the power supply.

As shown in fig. 9, the output voltage regulating circuit includes a compensation circuit 10 and an error amplifying circuit 20, the compensation circuit 10 includes a load current compensation unit 101, an input voltage compensation unit 110, a compensation resistor R1, and a current stabilizing unit 102, an input terminal of the load current compensation unit 101 is connected to an output terminal of the error amplifying circuit 20, an output terminal of the load current compensation unit is connected to a compensation resistor R1 and a non-inverting input terminal of the error amplifying circuit 20, respectively, and a second terminal of the compensation resistor R1 is connected to the current stabilizing unit 102.

The input terminal of the input voltage compensation unit 110 is configured to receive an input voltage Vm, the output terminal of the input voltage compensation unit 110 is connected to the first terminal of the compensation resistor R1, the inverting input terminal of the error amplification circuit 20 is configured to sample an output voltage, and the output terminal of the error amplification circuit 20 is configured to be connected to the modulation circuit 30.

In the output voltage regulating circuit with the above design, the load current compensation unit 101 generates the load compensation current I1 according to the error signal Veao output by the error amplifying circuit 20, and further forms the load compensation voltage Vcomp1 according to the load compensation current I1 and the compensation resistor R1; the input voltage compensation unit 110 generates an input voltage compensation current I2 according to the input voltage Vm, and further forms an input compensation voltage Vcomp2 according to the input voltage compensation current I2 and the compensation resistor R1, so that a load compensation voltage Vcomp1 and an input compensation voltage Vcomp2 are formed and output to the non-inverting input terminal of the error amplification circuit 20.

The load compensation current I1 formed by the load current compensation unit 101 is positively correlated with the error signal Veao, and the error signal Veao is positively correlated with the load current, so that the load current is positively correlated with the load compensation current I1 and the load compensation voltage Vcomp 1. The input voltage compensation current I2 formed by the input voltage compensation unit 110 is positively correlated with the input voltage Vm, and the input voltage compensation current I2 is positively correlated with the input compensation voltage Vcomp2, so that the input voltage Vm is positively correlated with the input compensation voltage Vcomp 2.

Assuming that the load current increases and the input voltage also increases, first, the load current increase causes the load compensation current I1 and the load compensation voltage Vcomp1 to increase; the increase of the input voltage causes the input compensation voltage Vcomp2 to also increase, so that the compensation total voltage Vcomp transmitted to the error amplifying circuit 20 increases to the sum of the variations of the load compensation voltage Vcomp1 and the input compensation voltage Vcomp2, the increased compensation total voltage Vcomp is transmitted to the non-inverting input terminal of the error amplifying circuit 20, so that the error amplifying circuit 20 outputs an error signal which changes correspondingly, so that the modulation circuit 30 adjusts the output voltage correspondingly according to the error signal, and further eliminates or reduces the situation that the output voltage decreases due to the increase of the load current and the increase of the input voltage, thereby realizing the constant output of the output voltage of the power supply. When the load current is reduced and the input voltage is reduced, the principle is similar, and the description is omitted here.

It should be noted here that the load current compensation unit 101 in this embodiment is the same as the load current compensation unit 101 in the first embodiment, the input voltage compensation unit 110 in this embodiment is the same as the input voltage compensation unit 110 in the second embodiment, and the current stabilization unit 102 is the same as the current stabilization unit 102 in the first embodiment, which is not described again here.

In an alternative embodiment of this embodiment, as shown in fig. 10, the output voltage regulating circuit may further include a compensation resistor R9, a first end of the compensation resistor R9 is connected to the output terminal of the load current compensation unit 101, and a second end of the compensation resistor R9 is connected to the first end of the compensation resistor R1.

Based on the above, if the first compensation voltage Vcomp1 is I1 (R1+ R9) and the second compensation voltage Vcomp2 is I2R 1, then the total compensation voltage Vcomp1+ Vcomp2 is I1 (R1+ R9) + I2R 1.

Fourth embodiment

The present application provides a constant voltage output system, as shown in fig. 11, the constant voltage output system includes a rectification module 1, a constant voltage control chip 2 and a buck conversion module 3, the constant voltage control chip 2 includes an output voltage regulating circuit 4 described in the first embodiment, the second embodiment or the third embodiment.

The input end of the rectification module 1 is used for receiving alternating current, the output end of the rectification module 1 is coupled with the constant voltage control chip 2 and the step-down conversion module 3, the output end of the step-down conversion module 3 is connected with the inverted input end of the error amplification circuit 20, a controllable switch tube Q1 can be arranged in the constant voltage control chip 2, the duty ratio of the controllable switch tube Q1 determines the voltage output by the step-down conversion module 3 to a load, namely determines the output voltage Vout; the output terminal of the error amplifying circuit 20 is connected to the control terminal of the controllable switch Q1, so that the constant voltage control chip 2 adjusts the output voltage Vout according to the internal output voltage adjusting circuit 4.

In the constant voltage output system designed above, the rectification module 1 rectifies and converts the alternating current V (which may be the commercial power 220V) into the input voltage Vm, and the input voltage Vm is transmitted to the step-down conversion module 3 for step-down conversion and then provides the output voltage Vout for the external load, the output voltage Vout regulated in the present application scheme is the voltage output by the load at the two ends of the step-down conversion module 3, and the output voltage Vout is transmitted back to the inverting input terminal of the error amplification circuit 20 in the constant voltage control chip 2, so as to regulate the output voltage according to the manner of the first embodiment, the second embodiment or the third embodiment.

When the constant voltage control chip 2 has the input voltage compensation unit 110 of the second embodiment or the third embodiment, the input voltage Vm is also transmitted to the input voltage compensation unit 110 in the constant voltage control chip 2, so as to eliminate or reduce the influence of the variation of the input voltage Vm on the output voltage Vout based on the manner of the second embodiment or the third embodiment.

As a possible implementation manner, the error amplifying circuit 20 may be connected to the control terminal of the controllable switch Q1 through a modulation circuit 30, the modulation circuit 30 outputs a corresponding modulation signal to the control terminal of the controllable switch Q1 based on the error signal output by the error amplifying circuit 20, and then controls the duty ratio of the controllable switch Q1 to adjust the output voltage Vout, thereby implementing a constant voltage output. Here, it should be noted that the sampled voltage VL of the peak current is a sampled voltage at a point a in fig. 11.

In the description of the present application, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the application usually place when using, and are only used for convenience in describing the present application and simplifying the description, but do not indicate or imply that the devices or elements that are referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

It should also be noted that, unless expressly stated or limited otherwise, the terms "disposed" and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by 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.