阅读说明：本技术 跨阻放大电路及通讯装置 (transimpedance amplifier circuit and communication device ) 是由 罗贤亮 于 2018-06-05 设计创作，主要内容包括：本公开涉及一种跨阻放大电路及通讯装置。一种跨阻放大电路,包括：放大电路,其具有输入端和输出端,所述放大电路被配置为藉由所述输入端获取输入电流,并于所述输出端产生输出电压；及负反馈电路,其与所述放大电路连接,并被配置为当所述输入电流改变时,根据所述输出电压和参考电压的差调整所述输入端的电压。一种通讯装置,其具有接收装置,所述接收装置包括所述的跨阻放大电路。(The disclosure relates to a transimpedance amplification circuit and a communication device. A transimpedance amplification circuit comprising: an amplifying circuit having an input terminal and an output terminal, the amplifying circuit configured to obtain an input current via the input terminal and generate an output voltage at the output terminal; and a negative feedback circuit connected to the amplifying circuit and configured to adjust a voltage of the input terminal according to a difference between the output voltage and a reference voltage when the input current changes. A communication device is provided with a receiving device, and the receiving device comprises the transimpedance amplification circuit.)

1. A transimpedance amplification circuit comprising:

An amplifying circuit having an input terminal and an output terminal, the amplifying circuit configured to obtain an input current via the input terminal and generate an output voltage at the output terminal; and

A negative feedback circuit connected to the amplification circuit and configured to adjust a voltage of the input terminal according to a difference between the output voltage and a reference voltage when the input current changes.

2. The transimpedance amplification circuit according to claim 1, wherein the negative feedback circuit is configured to decrease the voltage of the input terminal according to a difference between the output voltage and a reference voltage when the input current increases.

3. The transimpedance amplification circuit according to claim 1, wherein the amplification circuit comprises:

A first transistor having a source, a drain, and a gate, wherein the gate of the first transistor is connected to the input terminal, and the source of the first transistor is connected to a ground terminal;

A second transistor having a source, a drain, and a gate, wherein the gate of the second transistor is connected to the output terminal;

A first resistor connected between the input terminal and the source of the second transistor;

A second resistor, a first terminal of the second resistor being connected to the gate of the second transistor, a second terminal of the second resistor being connected to a first power supply terminal;

A first terminal of the direct current source is connected to the source of the second transistor, and a second terminal of the direct current source is connected to the ground terminal.

4. The transimpedance amplification circuit according to claim 3, wherein the negative feedback circuit comprises:

A first amplifier including a first input terminal, a second input terminal, and an output terminal, the first input terminal being connected to the output terminal of the amplifying circuit, the second input terminal being connected to the reference voltage;

A third transistor having a source, a drain, and a gate, wherein the gate of the third transistor is connected to the output terminal of the first amplifier, and the source of the third transistor is connected to the ground terminal.

5. The transimpedance amplification circuit according to claim 4, wherein a drain of the third transistor is connected to a source of the second transistor.

6. The transimpedance amplification circuit according to claim 5, wherein a drain of the first transistor is connected to the first terminal of the second resistor.

7. The transimpedance amplification circuit according to claim 5, wherein the amplification circuit further comprises:

A fourth transistor including a source, a drain, and a gate, the source of the fourth transistor being connected to the drain of the first transistor, the drain of the fourth transistor being connected to the first terminal of the second resistor, the gate of the fourth transistor being connected to the bias voltage terminal and receiving the bias voltage.

8. The transimpedance amplification circuit according to claim 7, wherein the amplification circuit further comprises:

And the input end of the second amplifier is connected with the source electrode of the fourth transistor, and the input end of the second amplifier is connected with the grid electrode of the fourth transistor.

9. The transimpedance amplification circuit according to claim 4, wherein a drain of the third transistor is connected to the input terminal of the amplification circuit.

10. The transimpedance amplification circuit according to any one of claims 1 to 9, wherein the transimpedance amplification circuit further comprises:

A photo-sensing device connected to an input of the amplification circuit and configured to provide the input current.

11. The transimpedance amplifier circuit according to any of claims 1-9, wherein the transimpedance amplifier circuit is formed using a CMOS process, a BiCMOS process, or a bipolar process.

12. A communication device having a receiving device comprising a transimpedance amplification circuit according to any one of claims 1 to 11.

Technical Field

The present disclosure relates to amplifier circuits, and more particularly to a transimpedance amplifier circuit and a communication device.

Background

The following description and examples are not admitted to be prior art by virtue of their inclusion in this section.

A Transimpedance Amplifier (TIA) is typically used to convert an input current signal to a corresponding output voltage signal. The transimpedance amplifier is generally configured to receive a current signal from a previous detection circuit, and the current signal output from the previous detection circuit is received by the transimpedance amplifier and converted into a corresponding voltage signal that can be processed by a processor of a subsequent stage of the transimpedance amplifier. The detection circuit of the previous stage is usually a sensing device, and the processor of the next stage is usually used for processing the voltage signal.

Disclosure of Invention

An embodiment of the present disclosure provides a transimpedance amplifier circuit, including: an amplifying circuit having an input terminal and an output terminal, the amplifying circuit configured to obtain an input current via the input terminal and generate an output voltage at the output terminal; and a negative feedback circuit connected to the amplifying circuit and configured to adjust a voltage of the input terminal according to a difference between the output voltage and a reference voltage when the input current changes.

The embodiment of the present disclosure further provides a communication device, which has a receiving device, wherein the receiving device includes the transimpedance amplification circuit.

Drawings

Fig. 1 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Fig. 2 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Fig. 3 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Fig. 4 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Fig. 5 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Fig. 6 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure.

Detailed Description

The disclosed embodiments provide many different embodiments or examples for implementing different features of the disclosed embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure.

For convenience in description, "first," "second," "third," and the like may be used herein to distinguish between different components of a figure or series of figures. "first," "second," "third," etc. are not intended to describe corresponding components.

Fig. 1 is a schematic structural diagram of a transimpedance amplifier circuit according to an embodiment of the present disclosure. The transimpedance amplifier circuit comprises an input end and an output end V_OUTa first transistor M₁A second transistor M₂A first resistor R_FA second resistor R_LA first DC source I_DC1And a second direct current source I_DC2。

According to an embodiment of the present disclosure, the first transistor M₁Can be used as the input terminal of the transimpedance amplifier circuit and the second transistor M₂Can be used as the output end V of the transimpedance amplifier circuit_OUT. First transistor M₁Is configured to receive an input current i provided by the photo-sensing device PD_IN1Wherein the photo sensor device PD may be a photodiode, but is not limited thereto. The other end of the photoelectric sensing device PD and the first power supply end V_DD1Connected to a first supply terminal V_DD1For providing an operating voltage to the photo sensor device PD. First resistor R_FIs connected to the first transistor M₁Gate and output terminal V of_OUTIn the meantime. First transistor M₁Is connected to ground GND, a first transistor M₁Is connected to the second resistor R_LOne terminal of (1), a second resistor R_LAnd the other end of the second power supply terminal V_DD2And (6) electrically connecting. Second transistor M₂Gate of and the first transistor M₁Is connected with the drain of the second transistor, the drain of the second transistor is connected with the second power supply terminal V_DD2And (4) connecting. A first DC source I_DC1is connected in series to the second transistor M₂Between the source of (1) and ground GND. A second DC source I_DC2And a second resistor R_LAre connected in parallel. According to an embodiment of the present disclosure, the second DC source I_DC2Is configured to provide a current I_DC3To the first transistor M₁Of the substrate.

The transimpedance amplifier circuit is a single-ended input transimpedance amplifier circuit which converts an optical signal induced by the photoelectric sensing device PD into a current signal i_IN1The input current signal is used as the input current signal of the single-ended transimpedance amplifier circuit, and the transimpedance amplifier circuit receives the input current signal and uses the amplified voltage signal to output the voltage signal from the output end V_OUTAnd (6) outputting. The transimpedance amplification circuit realizes linear amplification of a current signal. The photoelectric signal received by the photo-sensing device PD generally has a very large dynamic range, and when the input current is large and exceeds the linear input range of the transimpedance amplifier circuit, the linearity performance of the transimpedance amplifier circuit is reduced, thereby limiting the application of the transimpedance amplifier circuit。

Fig. 2 is a schematic structural diagram of a transimpedance amplifier circuit according to an embodiment of the present disclosure. The transimpedance amplifier circuit comprises an input end I_INAnd an output end V_OUTA first transistor Q₁A second transistor Q₂A third transistor Q₃A first resistor R_fA second resistor R_CAnd a first DC source I_DC1. According to an embodiment of the present disclosure, the first transistor Q₁The base electrode of the transimpedance amplifier circuit is used as an input end I of the transimpedance amplifier circuit_INAnd a second transistor Q₂The collector of the resistor is used as the output end V of the transimpedance amplifier circuit_OUT. A first transistor Q₁Is connected to the ground terminal, a first transistor Q₁Collector of and the second transistor Q₂Emitter connection of, a second transistor Q₂Collector and second resistor R_CIs connected to one terminal of a second transistor Q₂Is used for connecting a bias circuit for the second transistor Q₂Base electrode of (2) providing bias voltage V_bias. Second resistor R_CAnother end of (1) and a power supply end V_CCAnd (4) connecting. Third transistor Q₃Base and second transistor Q₂Is connected with the collector and has an output end V_OUTAnd a second resistor R_CIs connected at one end. Third transistor Q₃Collector and supply terminal V of_CCConnected to a first DC source I_DC1Is connected to the first resistor R_fBetween one end of (a) and ground. First resistor R_fIs connected to the first transistor Q₁Base and third transistor Q₃Between the emitters.

For a single-ended transimpedance amplifier circuit, a second resistor R flows_CThe quiescent current of (c) is equal to (vcc-vbe1-vbe3)/rc, wherein vcc is the power supply terminal V_CCVbe1 is the first transistor Q₁vbe3 is the voltage value of the PN junction voltage between the base and the emitter of the third transistor Q₃Rc is a second resistor R_CThe resistance value of (2). Therefore, the branch quiescent current is directly related to two PN junction voltages, andSemiconductor technology, environment temperature and power supply voltage are sensitive, branch current is unstable, reliability of the single-ended input transimpedance amplification circuit is affected, and requirements of a system power supply module are increased, so that complexity of a system is increased.

Fig. 3 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure. The transimpedance amplifier circuit of fig. 3 includes an amplifier circuit and a negative feedback circuit.

The amplifying circuit comprises an input end and an output end V_OUTA first transistor M₁a second transistor M₂A first resistor R_FA second resistor R_LDC source I_DC1. According to an embodiment of the present disclosure, the first transistor M₁And a second transistor M₂Each having a source, a drain and a gate, wherein the first transistor M₁Can be used as the input terminal of the trans-impedance amplifying circuit and the first transistor M₁Can be used as the output end V of the transimpedance amplifier circuit_OUTthe photo sensor device PD may be a photodiode, but is not limited thereto. First transistor M₁Is configured to receive an input current i provided by the photo-sensing device PD_IN1. First resistor R_FIs connected to the first transistor M₁and the second transistor M₂Between the source electrodes of (1). First transistor M₁Is connected to ground GND, a first transistor M₁Is connected to the second resistor R_LOne terminal of (1), a second resistor R_LAnother end of (1) and a power supply end V_DD2And (6) electrically connecting. Second transistor M₂Gate of and the first transistor M₁Is connected to the drain of the second transistor M₂Drain and supply terminal V of_DD2And (4) connecting. DC source I_DC1Is connected to the second transistor M₂Between the source of (1) and ground GND.

The negative feedback circuit includes a third transistor M₃And an amplifier OP₁. According to an embodiment of the present disclosure, the amplifier OP₁May be an operational Amplifier (OPAmp). The amplifier OP₁Comprising a first input (as indicated in fig. 3) "A terminal of- "), a second input terminal (e.g., the terminal marked with" + "in FIG. 3), and an output terminal, a first input terminal, and an output terminal V of the amplifying circuit_OUTConnected to a second input terminal with a reference voltage V_REFAnd (4) connecting. The third transistor M₃Having a source, a drain and a gate, wherein a third transistor M₃Gate of and amplifier OP₁Is connected to the output terminal of the third transistor M₃Is connected to ground GND, and a third transistor M₃And the second transistor M₂Source electrode, direct current source I_DC1And a second resistor R_FAnd (4) connecting. According to an embodiment of the present disclosure, the first transistor M₁And a second transistor M₃For operating in an amplifying state, the second transistor M₂For use as a source follower.

First transistor M₁is used as the input end of the transimpedance amplifier circuit and is used for receiving an input current i_IN1. The amplifier circuit of the transimpedance amplifier circuit receives an input current i_IN1The output voltage after linear amplification is generated through an output end V_OUTAnd (6) outputting. When the input current i of the trans-impedance amplifier_IN1At the time of increase, through the first resistor R_FSo that the first resistor R is increased_FThe voltage across the first transistor M increases₁And a second resistor R_LCurrent I on the branch_DC2Become larger, the second resistor R_LThe voltage difference across increases. Due to the output end V_OUTThe output voltage of the power supply terminal V_DD2Subtracting the second resistor R_LThe voltage difference between both ends, so that the second resistor R is used as_LWhen the voltage difference between the two ends is increased, the output end V of the amplifying circuit_OUTThe output voltage of (2) is reduced, resulting in a degradation of linearity performance. Due to the amplifier OP₁By setting a reference voltage V_REFAnd will reference voltage V_REFAnd an output terminal V_OUTis amplified and the output end V_OUTWill cause the voltage difference to become larger, and the amplifier OP will therefore₁The amplified voltage at the output terminal increases, which causes the third transistor M to increase₃Between the gate and the source ofIncreases so that the voltage of the node 1 decreases, i.e., the first resistor R_FThe voltage drop across the first transistor M is compensated for₁To achieve negative feedback. Therefore, compared with the transimpedance amplifier circuits shown in fig. 1 and 2, the negative feedback circuit of the transimpedance amplifier circuit shown in fig. 3 can improve the linearity of the transimpedance amplifier circuit and increase the linear input range under the condition of increasing the input current, and vice versa. In other words, the negative feedback circuit of fig. 3 may be connected to the amplifying circuit and configured to output a current i when the current i is input_IN1When changed, according to the output terminal V_OUTand the reference voltage V_REFThe difference of (a) adjusts the voltage at the input terminal.

In addition, the negative feedback circuit stabilizes the output terminal V_OUTThe static voltage of (2) to make the output end V_OUTThe static voltage of the voltage regulator is stabilized at a reference voltage V_REFSo as to flow through the second resistor R_LQuiescent current I of branch_DC2Is (vdd2-vref)/rl, wherein vdd2 is the first power supply terminal V_DD2With vref being the reference voltage V_REFThe voltage value of (3), rl is the second resistor R_LThe resistance value of (2). Compared with the transimpedance amplifier circuit shown in fig. 2, the transimpedance amplifier circuit shown in fig. 3 can greatly reduce the sensitivity of the branch static circuit to semiconductor process, power supply and environmental problems, so that the branch static current is stable and reliable.

In addition, the second power supply terminal V of the transimpedance amplifier circuit of FIG. 1_DD2The minimum voltage value that must be satisfied is V_GS1+V_GS2+V_DSIn which V is_GS1Is a first transistor M₁Voltage value between the gate and the source, V_GS2Is a second transistor M₂Voltage value between the gate and the source of (1) and V_DSIs a second DC source I_DC2The voltage difference across the terminals. And the supply terminal V of the transimpedance amplifier circuit of FIG. 3_DD2The minimum voltage value that must be met is only vds3+ vgs2+ idc2 xrl, where vds3 is the third transistor M₃The voltage between the drain and the source of (1), vgs2 is the second transistor M₂Is the value of the voltage between the gate and the source of (1), idc2 is the quiescent current I_DC2The current value of (1). Therefore, the transimpedance amplifier circuit of fig. 3 has lower power consumption than the transimpedance amplifier circuit of fig. 1.

Fig. 4 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure. The transimpedance amplifier circuit of the present embodiment is similar to the transimpedance amplifier circuit in fig. 3, and one difference is that: the amplifying circuit of fig. 4 further includes: fourth transistor M₄Including a source, a drain and a gate, a fourth transistor M₄And the first transistor M₁Is connected to the drain of the fourth transistor M₄Drain electrode of and a second resistor R_LIs connected to the first terminal of the fourth transistor M₄Gate of and bias voltage terminal V_BIAConnected and configured to receive a bias voltage.

Wherein bias voltage terminal V_BIAAn external bias circuit can be connected, and the first transistor M₁And a fourth transistor M₄And forming a vertical cascade (Cascode) amplification structure, wherein the Cascode amplification structure is a Cascode structure. By providing a fourth transistor M₄To reduce the first transistor M₁The linearity of the transimpedance amplifier circuit is further improved.

Fig. 5 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure. The transimpedance amplifier circuit of the present embodiment is similar to the transimpedance amplifier circuit in fig. 4, and one difference is that: the amplifying circuit further includes: second amplifier OP₂A second amplifier OP₂And the fourth transistor M₄Is connected to the source of a second amplifier OP₂And the fourth transistor M₄Is connected to the gate of (a).

Wherein the second amplifier OP₂And a fourth transistor M₄Form a negative feedback loop, and the first transistor M₁A fourth transistor M₄And a second amplifier OP₂Forming a Regulated Cascode structure, wherein the Regulated Cascode structure is a Regulated Cascode structure. This may further reduce the first transistor M₁And attenuates the first transistor M₁Of the drain electrodeAnd the linearity of the transimpedance amplification circuit is further improved.

Fig. 6 is a schematic circuit diagram of a transimpedance amplifier according to an embodiment of the present disclosure. The transimpedance amplifier circuit of the present embodiment is similar to the transimpedance amplifier circuit in fig. 3, and one difference is that: third transistor M of transimpedance amplifier circuit of fig. 6₃Is connected to the input terminal of the amplifier circuit. Wherein the input of the amplifying circuit is the first transistor M₁a gate electrode of (1).

The feedback principle of the transimpedance amplification circuit of this embodiment is similar to that in fig. 3, and in this embodiment, when the input current increases, the increase in the voltage at the input terminal of the amplification circuit is offset directly by the feedback circuit adjustment compensation, so that negative feedback adjustment is realized. So as to improve the linear input range of the transimpedance amplification circuit.

It should be noted that the differences between fig. 4 and fig. 5 with respect to fig. 3 may also be added to the solution of fig. 6 to form a corresponding solution.

In an embodiment of the present disclosure, the transimpedance amplifier circuit is formed by a CMOS process, a BiCMOS process, or a bipolar process, but is not limited thereto. The transimpedance amplifier circuit can be realized in a single integrated device or by adopting discrete components, and the specific realization mode can be selected according to the actual condition.

In summary, some embodiments of the disclosure have at least the following effects: the linear input range and the linearity are improved, so that the branch circuit has stable quiescent current, the stability and the reliability of the circuit are improved, and the power voltage of the normal work is reduced by more than one threshold voltage (or one PN junction voltage) under the condition of consuming the same current, namely, the power consumption of the circuit is reduced.

An embodiment of the present disclosure further provides a communication device having a transmitting device and a receiving device, wherein the receiving device includes the transimpedance amplifier of fig. 1 to 6.

In some embodiments of the present disclosure, the receiving device may be an optical receiver, but is not limited thereto. For example, the transimpedance amplifier circuit may serve as a front end of a mixer.

Reference throughout this specification to "one embodiment of the present disclosure" or similar terms means that a particular feature, structure, or characteristic described in connection with the other embodiments is included in at least one embodiment and may not necessarily be present in all embodiments. Thus, respective appearances of the phrase "one embodiment of the present disclosure" or similar terms in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment may be combined in any suitable manner with one or more other embodiments. It should be understood that other variations and modifications of the embodiments described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the present disclosure.

While the foregoing has been with reference to the disclosure of the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the disclosure. Therefore, the scope of the present disclosure should not be limited to the embodiments disclosed, but includes various alternatives and modifications without departing from the disclosure, which are encompassed by the claims of the present patent application.