Trans-impedance amplifier device for optical receiver

Abstract

A transimpedance amplifier device for an optical receiver disclosed by the present invention comprises a bias circuit, a transimpedance amplifier and an amplification driving circuit which are connected in sequence, the bias circuit comprises an upper bias structure and a lower bias structure, and the upper bias structure and the lower bias structure are both connected with the transimpedance amplifier to generate different bias currents. It is ensured that the photodiode PD1 can be conducted and generate light current when light passes through the photodiode PD1, the transimpedance amplifier is used for converting the current into voltage to be output, and the amplification driving circuit is used for amplifying the voltage. According to the optical receiver circuit, micro current generated by the photodiode can be converted into output voltage in a relatively high output range through the transimpedance amplifier, and compared with a traditional optical receiver circuit, the optical receiver circuit is relatively low in cost in circuit structure and has the advantages of low power consumption and high reliability. The driving capability of the circuit can be improved under the condition that a complex amplifier loop and a photoelectric conversion module are not needed, the output voltage in a high range is output, and the performance and the stability are further enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of optical communications, and in particular relates to a transimpedance amplifier device for an optical receiver. Background Art

[0002] Continuous advancements in fiber-optic communication technology have driven the development of fiber-optic receivers. A transimpedance amplifier (TIA), a specialized amplifier structure, converts tiny input current signals into corresponding voltage output signals. In fiber-optic receivers, TIA are typically located after photodetectors, converting the weak photocurrent signals generated by the photodetectors into observable voltage signals. While TIA offers advantages such as high gain, low noise, high input impedance, and good stability, they also limit their output voltage. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention provides a transimpedance amplifier device for an optical receiver, which solves the problem that the output voltage is limited when a transimpedance amplifier is applied to a conventional optical receiver circuit.

[0004] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a transimpedance amplifier device for an optical receiver, comprising a bias circuit, a transimpedance amplifier and an amplification drive circuit connected in sequence, the bias circuit comprising an upper bias structure and a lower bias structure, both of which are connected to the transimpedance amplifier to generate different bias currents to ensure that the photodiode PD1 can be turned on and generate photocurrent when light passes through, the transimpedance amplifier is used to convert the current into a voltage output, and the amplification drive circuit is used to amplify the voltage.

[0005] Furthermore: the bias circuit further includes a grounding resistor R1, a resistor R2 and a resistor R10;

[0006] The output end of the upper bias structure is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the input end of the transimpedance amplifier and one end of the resistor R2, the other end of the resistor R2 is respectively connected to the ground resistor R1 and the anode of the photodiode PD1, and the output end of the lower bias structure is connected to the cathode of the photodiode PD1.

[0007] Furthermore: the upper bias structure includes a resistor R3, a resistor R4, a grounding resistor R5, a transistor Q1, a transistor Q2 and a transistor Q3;

[0008] One end of the resistor R3 is connected to the VDD power supply and the collector of the transistor Q1 respectively, the other end of the resistor R3 is connected to the base of the transistor Q1 and the collector of the transistor Q2 respectively, the base of the transistor Q2 is connected to one end of the resistor R4, the base of the transistor Q3 and the collector of the transistor Q3 respectively, the emitter of the transistor Q2 is connected to one end of the resistor R5, the emitter of the transistor Q3 is connected to the other end of the resistor R4, the other end of the resistor R5 and the emitter of the transistor Q1 respectively, and serves as the output end of the upper bias structure.

[0009] Furthermore: the lower bias structure includes a resistor R6, a resistor R7, a grounding resistor R8, a resistor R9, a transistor Q4 and a transistor Q5;

[0010] One end of the resistor R6 is connected to the VDD power supply and the collector of the transistor Q4 respectively, the other end of the resistor R6 is connected to the base of the transistor Q4 and the collector of the transistor Q5 respectively, the emitter of the transistor Q4 is connected to one end of the resistor R7 and the grounding resistor R8 respectively, the base of the transistor Q5 is connected to the other end of the resistor R7 and one end of the resistor R9 respectively, the emitter of the transistor Q5 is grounded, and the other end of the resistor R9 serves as the output end of the lower bias structure.

[0011] Further: the transimpedance amplifier includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a grounding resistor R15, a transistor Q6, a transistor Q7, a transistor Q8 and a diode D1;

[0012] One end of the resistor R11 is connected to the VDD power supply and the collector of the transistor Q8, respectively. The other end of the resistor R11 is connected to the base of the transistor Q8 and the emitter of the transistor Q6, respectively. The collector of the transistor Q6 is grounded. The base of the transistor Q6 is connected to one end of the resistor R12 and the anode of the diode D1, respectively, and serves as the input end of the transimpedance amplifier. The cathode of the diode D1 is connected to one end of the resistor R13, the emitter of the transistor Q8, and the grounded resistor R15, respectively, and serves as the output end of the transimpedance amplifier. The other end of the resistor R12 is connected to the other end of the resistor R13 and one end of the resistor R14, respectively. The other end of the resistor R14 is connected to the emitter of the transistor Q7. The base and collector of the transistor Q7 are grounded.

[0013] Furthermore: the amplifying driving circuit includes a resistor R16, a resistor R17, a grounding resistor R18, a resistor R19, a resistor R20, a transistor Q9, a transistor Q10, a transistor Q11, a transistor Q12, a transistor Q13, a transistor Q14, a MOS transistor Q15 and a MOS transistor Q16;

[0014] One end of the resistor R16 serves as an input end of the amplifier drive circuit, the other end of the resistor R16 is connected to the base of the transistor Q9, the emitter of the transistor Q9 is grounded, the collector of the transistor Q9 is respectively connected to the collector of the transistor Q10, the base of the transistor Q10, the base of the transistor Q13, and one end of the resistor R17, the emitter of the transistor Q10 is respectively connected to the base of the transistor Q11 and the collector of the transistor Q11, the emitter of the transistor Q11 is respectively connected to the base of the transistor Q12 and the collector of the transistor Q12, and the emitter of the transistor Q12 is grounded;

[0015] The other end of resistor R17 is connected to the VDD power supply, the collector of transistor Q13, and one end of resistor R20, respectively. The emitter of transistor Q13 is connected to grounded resistor R18 and one end of resistor R19, respectively. The other end of resistor R19 is connected to the base of transistor Q14. The emitter of transistor Q14 is grounded. The collector of transistor Q14 is connected to the other end of resistor R20, the gates of MOS transistors Q15, and the gates of MOS transistors Q16, respectively. The source of MOS transistor Q15 is connected to the VDD1 power supply. The drain of MOS transistor Q15 is connected to the drain of MOS transistor Q16 and serves as the output end of the amplifier drive circuit. The source of MOS transistor Q16 is grounded.

[0016] The beneficial effects of the present invention are:

[0017] (1) The present invention provides a transimpedance amplifier device for an optical receiver, which can convert the tiny current generated by a photodiode into an output voltage with a higher output range through a transimpedance amplifier. Compared with traditional optical receiver circuits, the present invention has not only a low cost in circuit structure, but also low power consumption. It can improve the driving capability of the circuit without the need for a complex amplifier loop and photoelectric conversion module, output a high range of output voltage, and further enhance performance and stability.

[0018] (2) The present invention further improves the output voltage range by adding a driver and a MOS tube to the next stage of the transimpedance amplifier. At the same time, due to the simple structure, the process manufacturing cost is greatly saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a circuit schematic diagram of a transimpedance amplifier device for an optical receiver according to the present invention.

[0020] Figure 2 This is the overall circuit working diagram of the present invention.

[0021] Figure 3 This is the principle structure diagram of the bias circuit.

[0022] Figure 4 This is the equivalent architecture diagram of the transimpedance amplifier.

[0023] Figure 5 This is the equivalent architecture diagram of the amplified driving circuit. DETAILED DESCRIPTION

[0024] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0025] like Figure 1 As shown, in one embodiment of the present invention, a transimpedance amplifier device for an optical receiver includes a bias circuit, a transimpedance amplifier and an amplification drive circuit connected in sequence, the bias circuit includes an upper bias structure and a lower bias structure, the upper bias structure and the lower bias structure are both connected to the transimpedance amplifier, and are used to generate different bias currents to ensure that the photodiode PD1 can be turned on and generate photocurrent when light passes through, the transimpedance amplifier is used to convert the current into a voltage output, and the amplification drive circuit is used to amplify the voltage.

[0026] like Figure 2 As shown, the photodiode PD1 is turned on by the bias circuit inside the transimpedance amplifier device. After receiving the light signal, it generates a photocurrent, which is converted into a voltage by the internal transimpedance amplifier. The photocurrent is amplified by the amplifier drive circuit and then output. Finally, it is further amplified by the external MOS tube to obtain the output voltage.

[0027] The bias circuit also includes a ground resistor R1, a resistor R2, and a resistor R10;

[0028] The output end of the upper bias structure is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the input end of the transimpedance amplifier and one end of the resistor R2, the other end of the resistor R2 is respectively connected to the ground resistor R1 and the anode of the photodiode PD1, and the output end of the lower bias structure is connected to the cathode of the photodiode PD1.

[0029] In this embodiment, the present invention adds a bias circuit to the upper stage of the transimpedance amplifier to provide a current source for the transimpedance amplifier, thereby preventing the current at the input end of the transimpedance amplifier from being zero.

[0030] The upper bias structure includes resistor R3, resistor R4, grounding resistor R5, transistor Q1, transistor Q2 and transistor Q3;

[0031] One end of the resistor R3 is connected to the VDD power supply and the collector of the transistor Q1 respectively, the other end of the resistor R3 is connected to the base of the transistor Q1 and the collector of the transistor Q2 respectively, the base of the transistor Q2 is connected to one end of the resistor R4, the base of the transistor Q3 and the collector of the transistor Q3 respectively, the emitter of the transistor Q2 is connected to one end of the resistor R5, the emitter of the transistor Q3 is connected to the other end of the resistor R4, the other end of the resistor R5 and the emitter of the transistor Q1 respectively, and serves as the output end of the upper bias structure.

[0032] The lower bias structure includes resistor R6, resistor R7, grounding resistor R8, resistor R9, transistor Q4 and transistor Q5;

[0033] One end of the resistor R6 is connected to the VDD power supply and the collector of the transistor Q4 respectively, the other end of the resistor R6 is connected to the base of the transistor Q4 and the collector of the transistor Q5 respectively, the emitter of the transistor Q4 is connected to one end of the resistor R7 and the grounding resistor R8 respectively, the base of the transistor Q5 is connected to the other end of the resistor R7 and one end of the resistor R9 respectively, the emitter of the transistor Q5 is grounded, and the other end of the resistor R9 serves as the output end of the lower bias structure.

[0034] The transimpedance amplifier includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a grounding resistor R15, a transistor Q6, a transistor Q7, a transistor Q8 and a diode D1;

[0035] One end of the resistor R11 is connected to the VDD power supply and the collector of the transistor Q8, respectively. The other end of the resistor R11 is connected to the base of the transistor Q8 and the emitter of the transistor Q6, respectively. The collector of the transistor Q6 is grounded. The base of the transistor Q6 is connected to one end of the resistor R12 and the anode of the diode D1, respectively, and serves as the input end of the transimpedance amplifier. The cathode of the diode D1 is connected to one end of the resistor R13, the emitter of the transistor Q8, and the grounded resistor R15, respectively, and serves as the output end of the transimpedance amplifier. The other end of the resistor R12 is connected to the other end of the resistor R13 and one end of the resistor R14, respectively. The other end of the resistor R14 is connected to the emitter of the transistor Q7. The base and collector of the transistor Q7 are grounded.

[0036] The amplifying driving circuit includes a resistor R16, a resistor R17, a grounding resistor R18, a resistor R19, a resistor R20, a transistor Q9, a transistor Q10, a transistor Q11, a transistor Q12, a transistor Q13, a transistor Q14, a MOS transistor Q15, and a MOS transistor Q16;

[0037] One end of the resistor R16 serves as an input end of the amplifier drive circuit, the other end of the resistor R16 is connected to the base of the transistor Q9, the emitter of the transistor Q9 is grounded, the collector of the transistor Q9 is respectively connected to the collector of the transistor Q10, the base of the transistor Q10, the base of the transistor Q13, and one end of the resistor R17, the emitter of the transistor Q10 is respectively connected to the base of the transistor Q11 and the collector of the transistor Q11, the emitter of the transistor Q11 is respectively connected to the base of the transistor Q12 and the collector of the transistor Q12, and the emitter of the transistor Q12 is grounded;

[0038] The other end of resistor R17 is connected to the VDD power supply, the collector of transistor Q13, and one end of resistor R20, respectively. The emitter of transistor Q13 is connected to grounded resistor R18 and one end of resistor R19, respectively. The other end of resistor R19 is connected to the base of transistor Q14. The emitter of transistor Q14 is grounded. The collector of transistor Q14 is connected to the other end of resistor R20, the gates of MOS transistors Q15, and the gates of MOS transistors Q16, respectively. The source of MOS transistor Q15 is connected to the VDD1 power supply. The drain of MOS transistor Q15 is connected to the drain of MOS transistor Q16 and serves as the output end of the amplifier drive circuit. The source of MOS transistor Q16 is grounded.

[0039] The circuit operation mode of a transimpedance amplifier device for an optical receiver of the present invention is specifically as follows:

[0040] like Figure 3 As shown, in this embodiment, the working principle of the bias circuit is mainly based on the negative feedback loop composed of resistor R3 and transistor Q2. This design makes the output voltage V O Can remain stable. The derivation process is as follows:

[0041] First, the collector current I of Q1 can be derived from the circuit structure. c1 for:

[0042]

[0043] Where Vb is the voltage at the common node between the collector of transistor Q2 and resistor R3;

[0044] At the same time, according to Kirchhoff's voltage law and the amplification characteristics of the transistor, the relationship between the bias circuit output node voltage and the transistor can be obtained:

[0045] Vo1=Vbe1+Ib1·R4

[0046]

[0047] Where β1 is the amplification factor, Vbe1 is the voltage difference between the base and emitter of transistor Q2;

[0048] The current in the expression of node output voltage Vo1 is represented by voltage and resistance:

[0049]

[0050] At the same time, the node output voltage can be represented by the voltage difference of Q1:

[0051] Vo1=Vb-Vbe2

[0052] Where Vbe2 is the voltage difference between the base and emitter of transistor Q1;

[0053] Finally, the node output voltage Vo1 is expressed as a function of the transistor voltage and resistance. The node output voltage Vo1 is related to the resistance and Vbe1 and Vbe2. Adjusting the resistor ratio can adjust the output node voltage. Furthermore, the bias circuit module of the present invention incorporates negative voltage feedback, stabilizing Vo1 and reducing output resistance, allowing more current to flow into subsequent circuits.

[0054]

[0055] like Figure 4 As shown, the transimpedance amplifier converts the current into a voltage output. Figure 1 In the figure, diode D1 and transistor Q7 actually function as capacitors. When diode D1 conducts, a conduction voltage drop forms across resistors Rf and r'. Due to circuit analysis rules, resistor R2 is only considered as output impedance during small-signal analysis. The conversion circuit in this circuit operates on a similar principle to the bias circuit. The input impedance of the circuit is r', and the gain is -(Rf + r'). Adjusting the value of Rf can adjust the gain of the transimpedance amplifier.

[0056] like Figure 5 As shown, the amplifier driving circuit uses a first-stage inverter structure, which can enhance the driving capability of the circuit and drive the next-stage MOS tube amplifier circuit. Figure 2 In this circuit, the transistor acts as a diode. The specific analysis process is similar to the bias circuit module, and the input voltage V i and the output voltage V O The expression is:

[0057] V i =I b R1+V be

[0058] V O =V DD -βI b R2

[0059] The expression of output voltage is expressed in terms of input voltage:

[0060]

[0061] The node output voltage is output to the driving module composed of MOS tubes through another stage of amplifier circuit. It is worth noting that the power supply and ground of the driving circuit composed of MOS tubes are different from the power supply and ground connected to the previous and next stages. The amplifier circuit is driven by the inverter and output through the MOS tube. The MOS tube can output an output voltage of up to 18V, which enhances the output voltage range. It has a very simple structure, low cost, but high efficiency.

[0062] In the description of the present invention, it should be understood that the terms "center", "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "radial", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying the relative importance or the number of technical features implicitly specified. Therefore, the features defined by "first", "second", and "third" may explicitly or implicitly include one or more of such features.

Claims

1. A transimpedance amplifier device for an optical receiver, characterized in that It includes a bias circuit, a transimpedance amplifier and an amplification drive circuit connected in sequence. The bias circuit includes an upper bias structure and a lower bias structure. The upper bias structure and the lower bias structure are both connected to the transimpedance amplifier to generate different bias currents to ensure that the photodiode PD1 can be turned on and generate photocurrent when light passes through. The transimpedance amplifier is used to convert the current into a voltage output, and the amplification drive circuit is used to amplify the voltage.

2. The transimpedance amplifier device for an optical receiver according to claim 1, wherein The bias circuit also includes a ground resistor R1, a resistor R2, and a resistor R10; The output end of the upper bias structure is connected to one end of the resistor R10, the other end of the resistor R10 is respectively connected to the input end of the transimpedance amplifier and one end of the resistor R2, the other end of the resistor R2 is respectively connected to the ground resistor R1 and the anode of the photodiode PD1, and the output end of the lower bias structure is connected to the cathode of the photodiode PD1.

3. The transimpedance amplifier device for an optical receiver according to claim 2, wherein: The upper bias structure includes resistor R3, resistor R4, grounding resistor R5, transistor Q1, transistor Q2 and transistor Q3; One end of the resistor R3 is connected to the VDD power supply and the collector of the transistor Q1 respectively, the other end of the resistor R3 is connected to the base of the transistor Q1 and the collector of the transistor Q2 respectively, the base of the transistor Q2 is connected to one end of the resistor R4, the base of the transistor Q3 and the collector of the transistor Q3 respectively, the emitter of the transistor Q2 is connected to one end of the resistor R5, the emitter of the transistor Q3 is connected to the other end of the resistor R4, the other end of the resistor R5 and the emitter of the transistor Q1 respectively, and serves as the output end of the upper bias structure.

4. The transimpedance amplifier device for an optical receiver according to claim 2, wherein: The lower bias structure includes resistor R6, resistor R7, grounding resistor R8, resistor R9, transistor Q4 and transistor Q5; One end of the resistor R6 is connected to the VDD power supply and the collector of the transistor Q4 respectively, the other end of the resistor R6 is connected to the base of the transistor Q4 and the collector of the transistor Q5 respectively, the emitter of the transistor Q4 is connected to one end of the resistor R7 and the grounding resistor R8 respectively, the base of the transistor Q5 is connected to the other end of the resistor R7 and one end of the resistor R9 respectively, the emitter of the transistor Q5 is grounded, and the other end of the resistor R9 serves as the output end of the lower bias structure.

5. The transimpedance amplifier device for an optical receiver according to claim 1, wherein: The transimpedance amplifier includes a resistor R11, a resistor R12, a resistor R13, a resistor R14, a grounding resistor R15, a transistor Q6, a transistor Q7, a transistor Q8 and a diode D1; One end of the resistor R11 is connected to the VDD power supply and the collector of the transistor Q8, respectively. The other end of the resistor R11 is connected to the base of the transistor Q8 and the emitter of the transistor Q6, respectively. The collector of the transistor Q6 is grounded. The base of the transistor Q6 is connected to one end of the resistor R12 and the anode of the diode D1, respectively, and serves as the input end of the transimpedance amplifier. The cathode of the diode D1 is connected to one end of the resistor R13, the emitter of the transistor Q8, and the grounded resistor R15, respectively, and serves as the output end of the transimpedance amplifier. The other end of the resistor R12 is connected to the other end of the resistor R13 and one end of the resistor R14, respectively. The other end of the resistor R14 is connected to the emitter of the transistor Q7. The base and collector of the transistor Q7 are grounded.

6. The transimpedance amplifier device for an optical receiver according to claim 1, wherein: The amplifying driving circuit includes a resistor R16, a resistor R17, a grounding resistor R18, a resistor R19, a resistor R20, a transistor Q9, a transistor Q10, a transistor Q11, a transistor Q12, a transistor Q13, a transistor Q14, a MOS transistor Q15, and a MOS transistor Q16; One end of the resistor R16 serves as an input end of the amplifier drive circuit, the other end of the resistor R16 is connected to the base of the transistor Q9, the emitter of the transistor Q9 is grounded, the collector of the transistor Q9 is respectively connected to the collector of the transistor Q10, the base of the transistor Q10, the base of the transistor Q13, and one end of the resistor R17, the emitter of the transistor Q10 is respectively connected to the base of the transistor Q11 and the collector of the transistor Q11, the emitter of the transistor Q11 is respectively connected to the base of the transistor Q12 and the collector of the transistor Q12, and the emitter of the transistor Q12 is grounded; The other end of resistor R17 is connected to the VDD power supply, the collector of transistor Q13, and one end of resistor R20, respectively. The emitter of transistor Q13 is connected to grounded resistor R18 and one end of resistor R19, respectively. The other end of resistor R19 is connected to the base of transistor Q14. The emitter of transistor Q14 is grounded. The collector of transistor Q14 is connected to the other end of resistor R20, the gates of MOS transistors Q15, and the gates of MOS transistors Q16, respectively. The source of MOS transistor Q15 is connected to the VDD1 power supply. The drain of MOS transistor Q15 is connected to the drain of MOS transistor Q16 and serves as the output end of the amplifier drive circuit. The source of MOS transistor Q16 is grounded.

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