On-chip integrated signal processing method of photoelectric detection device

Abstract

The invention relates to an on-chip integrated signal processing method of a photoelectric detector, and belongs to the technical field of photoelectric detectors. According to the method, on-chip integration is carried out on a photoelectric detector and a corresponding signal processing circuit, photo-generated current of the photoelectric detector is converted into a voltage signal, signal processing such as voltage amplification, low delay and low output leakage is carried out, and finally a voltage or digital signal meeting the amplitude requirement is output. Therefore, on-chip real-time low-delay processing and fast data rate output of current signals are realized. The advantages of a photoelectric detector and a signal processing circuit are combined to achieve monolithic integration and process technology fusion, the processing rate and reliability can be effectively improved, the parasitic effect between elements is reduced, and function replacement of a discrete device board-level interconnection scheme is achieved; in addition, the invention has the characteristics of current conversion voltage and amplification, low delay, low output electric leakage, fast output rate, easy on-chip integration and the like, and is suitable for miniaturized, high-integration and low-cost photoelectric detection chips or application systems.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detectors and relates to an on-chip integrated signal processing method for a photoelectric detection device. Background Art

[0002] Silicon-based photodetectors are widely used in the fields of photoelectric detection and optical communication. As photoelectric detection systems develop towards miniaturization, high integration and low cost, the board-level connection solutions of traditional detectors, amplifier circuits and other discrete devices can no longer meet application requirements. Monolithic integrated structure detectors have the advantages of small area, low packaging cost and small parasitics, which reflect great competitive advantages and application prospects. With the development of process integration and fusion technology of detectors, silicon-based detectors are gradually integrated with Bipolar, CMOS and other processes, but their manufacturing processes have high compatibility requirements and are difficult to integrate. How to achieve high-performance on-chip processing and output of current signals while retaining the superior photoelectric detection performance of the detector has become a key technical problem that needs to be solved urgently. This is also of great significance to the improvement of the performance and process integration level of photoelectric detection systems. Summary of the invention

[0003] In view of this, an object of the present invention is to provide an on-chip integrated signal processing method for a photoelectric detection device, so as to achieve high gain, low delay, fast output rate, low power consumption, and on-chip integrated current signal processing of the photoelectric detection device.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] A method for processing on-chip integrated signals of a photoelectric detection device, wherein the method integrates the photoelectric detection device with a first circuit, a second circuit, and a third circuit on-chip, and specifically, the on-chip integration can be realized based on a standard bipolar process platform. The first circuit is used to convert the current signal output by the photoelectric detection device into a voltage signal, the second circuit is used to amplify the voltage signal output by the first circuit to meet the amplitude and gain bandwidth requirements, and the third circuit is used to output the amplified voltage signal to improve the output driving capability.

[0006] Furthermore, the first circuit includes an operational amplifier and a first resistor. The operational amplifier input is connected to the photodetector output, and the operational amplifier output is connected to the second circuit input; the first resistor is connected between the output and input of the operational amplifier. The input of the operational amplifier is also connected to a voltage reference module, which provides a bias voltage to the operational amplifier.

[0007] Furthermore, the second circuit includes a first transistor, a second transistor, a third resistor, a fourth resistor and a sixth resistor. The base of the first transistor is connected to the output end of the first circuit, the collector is respectively connected to the base of the second transistor and one end of the fourth resistor, and the emitter is grounded through the third resistor; the other end of the fourth resistor is connected to the power supply; the collector of the second transistor is connected to the power supply, the emitter is respectively connected to the third circuit and one end of the sixth resistor, and the other end of the sixth resistor is grounded. The power supply is provided by a reference voltage module.

[0008] Furthermore, the third circuit includes a third transistor, a fourth transistor, a seventh resistor, an eighth resistor, a ninth resistor and an OC output circuit. The base of the third transistor is connected to the output end of the second circuit, the collector is connected to the power supply through the eighth resistor, and the emitter is grounded through the seventh resistor; the base of the fourth transistor is connected to the collector of the third transistor, the collector is connected to the power supply, the emitter is respectively connected to the OC output circuit and one end of the ninth resistor, and the other end of the ninth resistor is grounded. The power supply is provided by a reference voltage module.

[0009] The OC output circuit includes a diode and a fifth transistor, wherein the anode and cathode of the diode are respectively connected to the base and collector of the fifth transistor; the base of the fifth transistor is connected to the emitter of the fourth transistor, the emitter is grounded, and the collector serves as an output port.

[0010] Furthermore, a second resistor is provided between the first circuit and the second circuit, and a fifth resistor is provided between the emitter of the third transistor and the base of the first transistor, and the gain and bandwidth of the voltage signal of the second circuit are controlled by the second resistor and the fifth resistor.

[0011] The beneficial effects of the present invention are:

[0012] (1) The present invention is based on a standard bipolar process platform and realizes on-chip real-time low-latency processing and fast data rate output of current signals while ensuring high-performance photoelectric detection of the detector unit.

[0013] (2) The present invention combines the advantages of the photoelectric detection unit and the signal processing circuit to achieve monolithic integration and process technology fusion, which can effectively improve the processing speed and reliability, reduce the parasitic effects between components, and realize the functional replacement of the discrete device board-level interconnection solution.

[0014] (3) The present invention has the performance characteristics of current conversion to voltage and amplification, low latency, low output leakage, fast output rate, and easy on-chip integration, and is suitable for application in miniaturized, highly integrated, low-cost photoelectric detection chips or application systems.

[0015] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 A schematic diagram of an on-chip integrated signal processing flow of a photodetector provided in one embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the structure of a signal processing circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0021] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0022] In response to the demand for on-chip integrated signal processing of photodetectors, the present invention provides an on-chip integrated signal processing method, which integrates photodetectors and current-to-voltage conversion devices, signal amplifier devices, output driver modules and other devices on a chip, converts the photocurrent of the photodetection unit into a voltage signal, and performs signal processing such as voltage amplification, low latency and low output leakage, and finally outputs a voltage or digital signal that meets the amplitude requirements, thereby meeting the demand for on-chip real-time low-latency processing and fast data rate output of current signals.

[0023] See also Figure 1 and Figure 2 , is an on-chip integrated signal processing structure provided by an embodiment of the present invention, wherein the photodetector is combined with a pre-amplifier, a post-amplifier, an output driver module, a reference voltage module and a reference voltage module to realize on-chip integrated current signal processing.

[0024] Specifically, Figure 1 As shown, the photoelectric detection unit first converts the optical signal into a current signal and inputs it into the pre-amplifier A1. The pre-amplifier A1 converts the current signal into a voltage signal through the feedback resistor. The post-amplifier A2 then amplifies the pre-stage output signal to a voltage signal that meets the amplitude and gain bandwidth requirements. Finally, the output driver module improves the driving capability of the output load. Among them, the pre-amplifier and the post-amplifier are connected through an isolation resistor to ensure the DC input and amplification factor of the post-stage circuit; the reference voltage module is used to provide a suitable voltage bias for the amplifier circuit; and the voltage reference module is used to provide a fixed reference voltage.

[0025] Figure 2 for Figure 1 The specific circuit structure connection diagram of the integrated structure shown in FIG. Figure 2 In the figure, the photodetector is modeled equivalently, and its equivalent circuit model consists of photocurrent Ip, equivalent capacitance Cp, and equivalent resistance R0. The photocurrent Ip enters the input end of the preamplifier A1, which can convert the photocurrent signal of the photodetector into a voltage signal of a certain amplitude for processing by the subsequent circuit. The preamplifier A1 can be implemented using a transimpedance amplifier (such as Figure 2 As shown), it can also be implemented by an amplifier circuit based on transistors, and by connecting feedback resistors in parallel at the input and output ends to form voltage parallel negative feedback, so that the amplifier circuit has the characteristics of low input impedance, large bandwidth, high gain, etc.

[0026] Among them, the transistor-based amplifier circuit is specifically composed of two groups of transistors and resistor interconnected circuit structures. One group is a transistor and its collector connected to a resistor to form a pre-common-emitter amplifier, and the other group is a transistor and its emitter connected to a resistor to form a post-emitter follower. The feedback resistor is connected across the base of the transistor of the first group and the emitter of the transistor of the second group. By reasonably designing the gain of the common-emitter amplifier and the resistance value of the feedback resistor, the photocurrent can be converted into a voltage with high gain and large bandwidth through the amplifier circuit structure.

[0027] The post-stage amplifier circuit can amplify the voltage signal output by the pre-stage amplifier circuit to an appropriate amplitude for processing by the post-stage circuit. The post-stage amplifier circuit includes a common emitter circuit composed of transistors T1 and T2, which is used to amplify the base input voltage, wherein the base of transistor T1 is connected to resistor R2, the collector is connected to resistor R4, and the emitter is connected to resistor R3. Transistor T2 acts as an emitter follower, and its emitter is connected to resistor R6. Because the bandwidth of the overall signal processing circuit depends on the minimum bandwidth of the pre-stage circuit and the post-stage circuit, it is necessary to consider the gain and bandwidth of the post-stage amplifier circuit. The pre-stage amplifier circuit and the post-stage amplifier circuit are connected through resistor R2, and resistor R2 and R5 jointly determine the gain and bandwidth of the post-stage amplifier circuit.

[0028] The feedback loop from node B to node A mainly provides a DC operating point for the base of transistor T1, and negative feedback can stabilize gain, improve bandwidth, etc. The first reference voltage module and the second reference voltage module provide a fixed reference voltage value for the photoelectric detection unit to ensure that it works in a reverse bias state.

[0029] The output driver module consists of two parts, one of which includes transistors T3 and T4, and the other is an OC output circuit.

[0030] Among them, transistors T3 and T4 form a common collector circuit with a gain of approximately 1. The base of transistor T3 is connected to the emitter of transistor T2, the collector is connected to resistor R8, and the emitter is connected to resistor R7. Transistor T4 acts as an emitter follower with its emitter connected to resistor R9. The common collector circuit structure adjusts the output resistance and the DC operating point of the next stage.

[0031] Transistor T5 and diode D1 form an OC output circuit structure. Diode D1 is forwardly connected across the base and collector of transistor T5. This circuit structure can adjust the circuit output driving capability, improve the charge release speed and control the output leakage current level. The output load adopts a pull-up structure resistor, which can output a voltage signal that meets the requirements of driving force, leakage current, voltage amplitude, etc.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for on-chip integrated signal processing of a photoelectric detection device, characterized in that: The photoelectric detection device is integrated on-chip with the first circuit, the second circuit and the third circuit; the current signal output by the photoelectric detection device is converted into a voltage signal through the first circuit; the voltage signal output by the first circuit is amplified to meet the amplitude and gain bandwidth requirements through the second circuit; the amplified voltage signal is output through the third circuit to improve the output driving capability.

2. The method according to claim 1, characterized in that The first circuit includes an operational amplifier and a first resistor; the operational amplifier input is connected to the photodetector output, and the operational amplifier output is connected to the second circuit input; the first resistor is connected across the output and input of the operational amplifier.

3. The method according to claim 2, characterized in that The operational amplifier input terminal is connected to a voltage reference module, and the voltage reference module provides a bias voltage to the operational amplifier.

4. The method according to claim 1, characterized in that: The second circuit includes a first transistor, a second transistor, a third resistor, a fourth resistor and a sixth resistor; the base of the first transistor is connected to the output end of the first circuit, the collector is respectively connected to the base of the second transistor and one end of the fourth resistor, and the emitter is grounded through the third resistor; the other end of the fourth resistor is connected to a power supply; the collector of the second transistor is connected to the power supply, the emitter is respectively connected to the third circuit and one end of the sixth resistor, and the other end of the sixth resistor is grounded.

5. The method according to claim 1, characterized in that The third circuit includes a third transistor, a fourth transistor, a seventh resistor, an eighth resistor, a ninth resistor and an OC output circuit; the base of the third transistor is connected to the output end of the second circuit, the collector is connected to the power supply through the eighth resistor, and the emitter is grounded through the seventh resistor; the base of the fourth transistor is connected to the collector of the third transistor, the collector is connected to the power supply, the emitter is respectively connected to the OC output circuit and one end of the ninth resistor, and the other end of the ninth resistor is grounded.

6. The method according to claim 5, characterized in that The OC output circuit includes a diode and a fifth transistor; the positive electrode and the negative electrode of the diode are respectively connected to the base and the collector of the fifth transistor; the base of the fifth transistor is connected to the emitter of the fourth transistor, the emitter is grounded, and the collector serves as an output port.

7. The method according to claim 4 or 5, characterized in that: A second resistor is arranged between the first circuit and the second circuit, and a fifth resistor is arranged between the emitter of the third transistor and the base of the first transistor. The gain and bandwidth of the voltage signal of the second circuit are controlled by the second resistor and the fifth resistor.

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