阅读说明：本技术 一种跨阻放大器、芯片和通信设备 (Transimpedance amplifier, chip and communication equipment ) 是由 卫宝跃 邸岳淼 于 2017-02-23 设计创作，主要内容包括：一种跨阻放大器、芯片和通信设备,用以解决目前跨阻放大器不能在降低功耗的同时提高滤波性能的问题,该跨阻放大器包括的第一电路、第二电路和第三电路由无源器件组成,第一电路、第二电路分别与电流源、运算放大器和第三电路相连,第一电路用于接收第一电流并为第三电路提供第三电压以及对第一电流进行滤波整形后转换为第一电压输出；第二电路用于接收第二电流并为第三电路提供第四电压以及对第二电流进行滤波整形后转换为第二电压输出；第三电路用于配合第一电路和第二电路进行整形滤波；运算放大器用于为第一电路提供小信号虚地点。由于增加了第三电路,因此相对于现有的跨阻放大器在降低功耗的同时提高了滤波性能。(A transimpedance amplifier, chip and communication equipment, in order to solve the problem that the transimpedance amplifier can not improve the filtering performance while reducing the power consumption at present, first circuit, second circuit and third circuit that the transimpedance amplifier includes are made up of passive device, first circuit, second circuit link with current source, operational amplifier and third circuit separately, the first circuit is used for receiving the first electric current and providing the third voltage for the third circuit and converting into the first voltage output after carrying on the filter shaping to the first electric current; the second circuit is used for receiving the second current, providing a fourth voltage for the third circuit, filtering and shaping the second current and converting the second current into a second voltage to be output; the third circuit is used for being matched with the first circuit and the second circuit to carry out shaping filtering; the operational amplifier is used to provide a small signal virtual ground for the first circuit. Due to the addition of the third circuit, compared with the existing trans-impedance amplifier, the power consumption is reduced, and meanwhile, the filtering performance is improved.)

1. An amplifier circuit, comprising:

an amplifier comprising a first input terminal and a second input terminal;

a first resistor and a second resistor coupled in series to the first input;

a third resistor and a fourth resistor coupled in series to the second input;

a third capacitor including a first terminal coupled between the first and second resistors and a second terminal coupled between the third and fourth resistors.

2. The amplifier circuit of claim 1, wherein the first input and the second input are to receive a pair of differential signals.

3. The amplifier circuit of claim 1, wherein the amplifier is an operational amplifier.

4. The amplifier circuit of claim 1, further comprising a first capacitor and a second capacitor, wherein two terminals of the first capacitor are coupled to the first input terminal and the first output terminal of the amplifier, respectively, and two terminals of the second capacitor are coupled to the second input terminal and the second output terminal of the amplifier, respectively.

5. The amplifier circuit of claim 4, wherein the first capacitance and the second capacitance are equal.

6. The amplifier circuit of claim 4, wherein the third capacitance is equal to the first and second capacitances.

7. A terminal device, characterized in that it comprises an amplifier circuit according to claims 1-6.

8. A chip comprising an amplifier circuit as claimed in claims 1-6.

9. An amplifier circuit, comprising:

an amplifier for amplifying the differential signal through two differential paths;

the first capacitor circuit and the second capacitor circuit are respectively bridged between the input and the input of the two differential paths;

the first and second capacitive circuits each include: at least two capacitors coupled to each other in series or in parallel.

Technical Field

The application relates to the technical field of chips, in particular to a transimpedance amplifier, a chip and communication equipment.

Background

Trans-Impedance amplifiers (TIA) can be used to convert current signals into voltage signals, and are widely used in the receiving part of sensors and radio frequency transceiver systems.

Currently, commonly used TIAs are the TIA of the first order active structure as shown in fig. 1a and the TIA of the second order active structure as shown in fig. 1 b. Specifically, although the TIA with the first-order active structure shown in fig. 1a includes only one operational amplifier, the TIA with the second-order active structure shown in fig. 1b is superior to the TIA with the second-order active structure shown in fig. 1a in terms of power consumption, but has poor filtering capability, and the TIA with the second-order active structure shown in fig. 1b has a strong suppression effect on out-of-band interference because it can perform second-order shaping filtering on the input current.

In summary, the TIAs of the current common structure all have performance bottlenecks.

Disclosure of Invention

The application provides a transimpedance amplifier, a chip and communication equipment, which are used for solving the problem that the transimpedance amplifier in the prior art cannot improve the filtering performance while reducing the power consumption.

In a first aspect, a transimpedance amplifier is provided, comprising: first circuit, second circuit, third circuit and operational amplifier, and first circuit, second circuit and third circuit are by passive device composition, wherein:

the first circuit is respectively connected with the current source, the operational amplifier and the third circuit, and is used for receiving the first current provided by the current source, providing a third voltage for the third circuit based on the first current, filtering and shaping the first current, converting the first current into a first voltage, outputting the first voltage and providing the first voltage to the operational amplifier;

the second circuit is respectively connected with the current source, the operational amplifier and the third circuit, and is used for receiving a second current provided by the current source, providing a fourth voltage for the third circuit based on the second current, filtering and shaping the second current, converting the second current into a second voltage, outputting the second voltage and providing the second voltage to the operational amplifier; the first current and the second current provided by the current source are two paths of currents in the differential current;

the third circuit is used for performing shaping filtering on the first current in cooperation with the first circuit and performing shaping filtering on the second current in cooperation with the second circuit according to the third voltage and the fourth voltage;

the operational amplifier is used to provide a small-signal virtual ground for the first circuit to enable the first current to enter the first circuit and a small-signal virtual ground for the second circuit to enable the second current to enter the second circuit.

The transimpedance amplifier in the embodiment of the present application includes only one operational amplifier, and the number of the operational amplifiers is reduced compared with the transimpedance amplifier with the second-order active structure shown in fig. 1b, so that the power consumption of the transimpedance amplifier in the embodiment of the present application is low, and the transimpedance amplifier in the embodiment of the present application includes the third circuit, and the third circuit can respectively shape and filter the currents in the first circuit and the second circuit according to the third voltage and the fourth voltage in cooperation with the first circuit and the second circuit, so that compared with the transimpedance amplifier with the first-order active structure shown in fig. 1a, the filtering performance is improved, and the capability of suppressing out-of-band interference is improved.

Based on the first aspect, in one possible design, the first circuit includes a first part and a second part, the first part is connected with the second part in parallel, and one end of the parallel connection is connected with the current source and the inverting input end of the operational amplifier, and the other end of the parallel connection is connected with the first output end of the operational amplifier;

the first part comprises at least one capacitor, and the at least one capacitor is connected in series and/or in parallel; the second part comprises at least one first resistor and at least one second resistor, the at least one first resistor is connected in series and/or in parallel, the at least one second resistor is connected in series and/or in parallel, and the at least one first resistor and the at least one second resistor are connected in series and the connection point of the series connection is connected with the third circuit.

Through the mode, the implementation mode of the first circuit is simplified.

Based on the first aspect, in one possible design, the second circuit includes a third part and a fourth part, the third part is connected in parallel with the fourth part, and one end of the parallel connection is connected with the current source and the positive input end of the operational amplifier, and the other end of the parallel connection is connected with the second output end of the operational amplifier;

the third part comprises at least one capacitor, and the at least one capacitor is connected in series and/or in parallel; the fourth part comprises at least one third resistor and at least one fourth resistor, the at least one third resistor is connected in series and/or in parallel, the at least one fourth resistor is connected in series and/or in parallel, the at least one third resistor and the at least one fourth resistor are connected in series, and the connecting point of the series connection is connected with the third circuit.

Through the mode, the implementation mode of the second circuit is simplified.

In a possible design according to the first aspect, the third circuit comprises at least one capacitor, and the at least one capacitor is connected in series and/or in parallel.

Through the mode, the implementation mode of the third circuit is simplified, and the third circuit with the design can be matched with the first circuit and the second circuit to improve the filtering capability, so that the out-of-band interference suppression capability of the trans-impedance amplifier is improved.

Based on the first aspect, in one possible design, the first circuit is composed of a first capacitor, a first resistor and a second resistor, the first resistor and the second resistor are connected in series and then connected in parallel with the first capacitor, one end of the parallel connection is connected with the current source and the reverse input end of the operational amplifier, and the other end of the parallel connection is connected with the first output end of the operational amplifier; the series connection point of the first resistor and the second resistor is connected to a third circuit.

Based on the first aspect, in one possible design, the second circuit is composed of a second capacitor, a third resistor and a fourth resistor, the third resistor and the fourth resistor are connected in series and then connected in parallel with the second capacitor, one end of the parallel connection is connected with the current source and the positive input end of the operational amplifier, and the other end of the parallel connection is connected with the second output end of the operational amplifier; the series connection point of the third resistor and the fourth resistor is connected with a third circuit;

and the first capacitor is equal to the second capacitor, and the resistance values of the first resistor, the second resistor, the third resistor and the fourth resistor are equal.

In a possible design based on the first aspect, the third circuit is composed of a third capacitor, and the third capacitor is equal to the first capacitor and the second capacitor.

In a second aspect, a chip is provided, comprising: the transimpedance amplifier of any one of the possible designs provided in the first aspect.

In a third aspect, a communication device is provided, which includes the chip provided in the second aspect.

Drawings

FIG. 1a is a prior art transimpedance amplifier of a first-order active configuration;

FIG. 1b is a prior art transimpedance amplifier of a second-order active structure;

fig. 2 is a schematic structural diagram of a transimpedance amplifier according to an embodiment of the present application;

fig. 3a and fig. 3b are schematic structural diagrams of a first circuit according to an embodiment of the present disclosure, respectively;

fig. 4a and 4b are schematic structural diagrams of a second circuit according to an embodiment of the present application, respectively;

FIG. 5 is a schematic diagram of a third circuit according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of a transimpedance amplifier according to an embodiment of the present application;

fig. 7 is a graph comparing the amplitude-frequency characteristics of the transimpedance amplifier and the first-order active transimpedance amplifier in the embodiment of the present application.

Detailed Description

In the embodiment of the present application, the term "and/or" is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in the embodiment of the present application generally indicates that the preceding and following related objects are in an "or" relationship.

Embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

The transimpedance amplifier is used for converting a current signal into a voltage signal, and can be integrated into a chip, applied to a communication device, for example, a receiving part of a sensor in the communication device, or applied to a radio frequency transceiver system of the communication device, and the like.

The transimpedance amplifier in the embodiment of the present application includes only one operational amplifier, and the number of the operational amplifiers is reduced compared with the transimpedance amplifier in the second-order active structure shown in fig. 1b, so the transimpedance amplifier in the embodiment of the present application has low power consumption, and the transimpedance amplifier in the embodiment of the present application includes the third circuit, and the third circuit can perform shaping filtering on currents in the first circuit and the second circuit by matching the first circuit and the second circuit according to the third voltage and the fourth voltage, so that compared with the transimpedance amplifier in the first-order active structure shown in fig. 1a, the filtering performance is improved, and the capability of suppressing out-of-band interference is further improved.

As shown in fig. 2, a transimpedance amplifier 200 according to an embodiment of the present application includes: the first circuit 210, the second circuit 220, the third circuit 230, and the operational amplifier 240, and the first circuit 210, the second circuit 220, and the third circuit 230 are composed of passive devices, in which:

the first circuit 210 is respectively connected to the current source, the operational amplifier 240 and the third circuit 230, and configured to receive a first current provided by the current source, provide a third voltage for the third circuit 230 based on the first current, filter and shape the first current, convert the first current into a first voltage, output the first voltage, and provide the first voltage to the operational amplifier 240;

specifically, the first terminal 211 of the first circuit 210 is respectively connected to one terminal of a current source and the inverting input terminal 241 of the operational amplifier 240, the second terminal 212 of the first circuit 210 is connected to the first output terminal 242 of the operational amplifier 240, the third terminal 213 of the first circuit 210 is connected to one terminal 231 of the third circuit 230, the first circuit 210 is configured to receive a first current provided by the current source through the first terminal 211, provide a third voltage to the terminal 231 of the third circuit 230 based on the first current, filter and shape the first current, convert the first current into a first voltage, and output the first voltage through the second terminal 212, because the second terminal 212 of the first circuit 210 is connected to the first output terminal 242 of the operational amplifier 240, the voltage of the first output terminal 242 is set to be the first voltage.

The second circuit 220 is respectively connected to the current source, the operational amplifier 240 and the third circuit 230, and is configured to receive a second current provided by the current source, provide a fourth voltage for the third circuit 230 based on the second current, filter and shape the second current, convert the second current into a second voltage, output the second voltage, and provide the second voltage to the operational amplifier 240; the first current and the second current provided by the current source are two currents in the differential current.

Specifically, the first end 221 of the second circuit 220 is connected to the other end of the current source and the positive input end 243 of the operational amplifier 240, the second end 222 of the second circuit 220 is connected to the second output end 244 of the operational amplifier 240, the third end 223 of the second circuit 220 is connected to the other end 232 of the third circuit 230, the second circuit 220 is configured to receive the second current provided by the current source through the first end 221 of the second circuit 220, provide a fourth voltage for the other end 232 of the third circuit 230 based on the second current, filter and shape the second current, convert the second current into the second voltage, and output the second voltage through the second end 222; since the second output terminal 244 of the operational amplifier 240 is connected to the second terminal 222, the second circuit 220 sets the voltage of the second output terminal 244 to the second voltage.

The third circuit 230 is used for performing shaping filtering on the first current in cooperation with the first circuit 210 and performing shaping filtering on the second current in cooperation with the second circuit 220 according to the third voltage and the fourth voltage.

Operational amplifier 240 is used to provide a small signal virtual ground for first circuit 210 to enable a first current to enter the first circuit and a small signal virtual ground for second circuit 220 to enable a second current to enter the second circuit.

And an operational amplifier 240 for providing a small signal virtual ground for the first circuit 210 and the second circuit 220, respectively.

Specifically, the operational amplifier 240 provides a small-signal virtual point to the first terminal 211 of the first circuit 210 through the inverting input terminal 241 so as to zero the voltage of the first terminal 211, thereby enabling the first current provided by the current source to enter the first circuit 210, and the operational amplifier 240 provides a small-signal virtual point to the first terminal 221 of the second circuit 220 through the forward input terminal 243 so as to zero the voltage of the first terminal 221, thereby enabling the second current provided by the current source to enter the second circuit 220.

It should be understood that the passive devices include capacitors, inductors, resistors, and the like, and the first circuit, the second circuit, and the third circuit may be implemented by forming a circuit with the passive devices, and the number and the type of the passive devices are not limited herein.

In one possible design, the first circuit 210 includes a first portion and a second portion, the first portion being connected in parallel with the second portion, and one end of the parallel connection (i.e., the first end 211) being connected to the inverting input 241 of the current source and operational amplifier 240, and the other end of the parallel connection (i.e., the second end 212) being connected to the first output 242 of the operational amplifier 240.

The first part comprises at least one capacitor, the at least one capacitor is connected in a series mode and/or a parallel mode, the second part comprises at least one first resistor and at least one second resistor, the at least one first resistor is connected in a series mode and/or a parallel mode, the at least one second resistor is connected in a series mode and/or a parallel mode, the at least one first resistor is connected with the at least one second resistor in a series mode, and a connection point of the at least one first resistor and the at least one second resistor which are connected in the series mode is connected with the third circuit 230. Specifically, the connection point of the series connection is connected to one end 231 of the third circuit 230, and the connection point of the series connection is the third end 213 of the first circuit 210.

For example, the first part of the first circuit 210 shown in fig. 3a includes three capacitors C1, C2 and C3, the second part includes a first resistor R1 and a second resistor R2, the first part of the first circuit 210 shown in fig. 3b includes a capacitor C1, and the second part includes a first resistor R1, a first resistor R2 and a second resistor R3, and the first circuit 210 in the embodiment of the present application may be connected equivalently to fig. 3a and 3b in addition to the first circuit 210 shown in fig. 3a and 3 b.

In one possible implementation, the second circuit 220 includes a third portion and a fourth portion, and one end of the parallel connection (i.e., the first end 221) is connected to the positive input end 243 of the current source and the operational amplifier 240, and the other end of the parallel connection (i.e., the second end 222) is connected to the second output end 244 of the operational amplifier 240.

The third part comprises at least one capacitor, the at least one capacitor is connected in series and/or in parallel, the fourth part comprises at least one third resistor and at least one fourth resistor, the at least one third resistor is connected in series and/or in parallel, the at least one fourth resistor is connected in series and/or in parallel, the at least one third resistor and the at least one fourth resistor are connected in series, and the connection point of the series connection is connected with the third circuit 230, specifically, the connection point of the series connection is connected with the other end 232 of the third circuit 230, and the connection point of the series connection is the third end 223 of the second circuit 220.

For example, the third portion of the second circuit 220 shown in fig. 4a includes three capacitors C1, C2, C3 and C4, the fourth portion includes a third resistor R1 and a fourth resistor R2, the third portion of the second circuit 220 shown in fig. 4b includes a capacitor C1, the third portion includes a third resistor R1, a third resistor R2 and a fourth resistor R3, and the second circuit 220 in the embodiment of the present application may be connected to the second circuit 220 shown in fig. 4a and 4b in an equivalent manner.

It should be understood that the connection manner of the first circuit 210 and the second circuit 220 in the embodiment of the present application may be the same or different, and the number of capacitors in the first circuit 210 and the second circuit 220, and the number of the first resistor, the second resistor, the third resistor, and the fourth resistor are not limited.

In one possible design, the third circuit 230 includes at least one capacitor, and the at least one capacitor is connected in series and/or in parallel.

Illustratively, if the third circuit 230 includes 2 capacitors C1 and C2, as shown in fig. 5, C1 and C2 of the third circuit 230 are connected in parallel, wherein one end of the third circuit 230 is connected to the third terminal 213 of the first circuit 210, and the other end of the third circuit 230 is connected to the third terminal 223 of the second circuit 220. It should be understood that the number of capacitors included in the third circuit 230 is not limited in the embodiment of the present application.

It should be noted that, in the embodiment of the present application, the sizes of the resistor and the capacitor may be set according to actual needs to obtain a desired voltage.

In the following, taking the transimpedance amplifier shown in fig. 6 as an example, assuming that the gain of the operational amplifier in the operating frequency range is infinite, the transimpedance amplifier according to the embodiment of the present application is qualitatively analyzed by a small signal equation.

As shown in fig. 6, the transimpedance amplifier includes C1, R1, R2, C3, C2, R3, R4, and an operational amplifier, wherein a current source supplies a differential current to the transimpedance amplifier, a first circuit is composed of C1, R1, and R2, a third circuit is composed of C3, and a second circuit is composed of C2, R3, and R4, wherein one path of the differential current flows into the first circuit through p1, and the other path of the differential current flows into the second circuit through n 1.

Since the inverting input terminal and the forward input terminal of the operational amplifier provide the small-signal virtual ground points for the first circuit 210 and the second circuit 220, assuming that voltages at points a, b, p2, and n2 shown in fig. 6 are Va, Vb, Vp, and Vn, respectively, a current supplied from the current source to the first circuit is i1, and a current supplied to the second circuit is i2, the sum of currents flowing through points a, b, c, and d, respectively, is 0, there are:

where ω is the operating frequency, when R1 ═ R2 ═ R3 ═ R4 ═ R, and C1 ═ C2 ═ C3 ═ C, then the transfer function is obtained:

it can be seen from the transfer function that the transfer function includes two poles and a zero, wherein one zero and one pole form a zero pole pair near the passband, and the flatness in the band is improved relative to the first-order active RC structure. If the corner frequency of the transimpedance amplifier is equal to 3dB, the transimpedance amplifier has better out-of-band rejection characteristics compared with a transimpedance amplifier with a first-order active structure. Fig. 7 shows that the transimpedance amplifier of the embodiment of the present application exhibits a second-order characteristic in the near passband and has better flatness, as shown in fig. 7, where a curve 1 is an amplitude-frequency characteristic curve when R1, R2, R3, R4, C1, C2, C3, and a curve 2 is an amplitude-frequency characteristic curve of the transimpedance amplifier of the first-order active structure when C3 is not added. In fig. 7, the 3dB corner frequencies of the curve 1 and the curve 2 are different, the 3dB corner frequency of the curve 1 is a, and the 3dB corner frequency of the curve 2 is B, if the transimpedance amplifier and the transimpedance amplifier of the first-order active structure in the embodiment of the present application have the same 3dB corner frequency requirement, the amplitude-frequency characteristic curve of the embodiment of the present application has a better out-of-band rejection characteristic, and meanwhile, only one operational amplifier is used, which saves power consumption compared with the transimpedance amplifier of the second-order active structure.

In addition, the embodiment of the application also provides a chip which comprises any transimpedance amplifier provided by the embodiment of the application.

The embodiment of the application also provides communication equipment comprising the chip provided by the embodiment of the application.

As the connection mode of the transimpedance amplifier in the chip or the communication device is as shown in fig. 1, the detailed description is omitted here.

Although specific embodiments which may be implemented have been described in this application, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the embodiments described herein and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.