High-linearity wide-range low-light detection circuit and device

Abstract

The utility model discloses a high-linearity wide-range low-light detection circuit and device. The high-linearity wide-range low-light detection circuit comprises a low-light detection sub-circuit, a logarithmic amplification sub-circuit and a linear amplification sub-circuit, the low-light-level detection sub-circuit converts a detected low-light-level signal into a current signal with logarithmic variation, the logarithmic amplification sub-circuit converts the current signal with logarithmic variation into a voltage signal with linear variation after current-voltage conversion and differential amplification, and the linear amplification sub-circuit adjusts the range of the voltage signal and outputs the voltage signal. And the external circuit or device obtains the optical power of the measured low-light signal according to the output voltage signal. According to the circuit, high-linearity, wide-range and high-precision detection of low light is realized.

Description

Technical Field

[0001] This utility model relates to the field of low-light detection electronic technology, specifically to a high-linearity, wide-range low-light detection circuit and device. Background Technology

[0002] Low-light detection technology is a very important part of the field of micro-signal measurement and one of the key technologies in optical communication networks.

[0003] Common low-light detection techniques include transimpedance amplification and logarithmic microcurrent amplification. Transimpedance amplification has a narrow measurement range; expanding the measurement range requires connecting multiple large resistors in parallel to achieve range switching, which introduces switching errors and affects measurement accuracy. Logarithmic microcurrent amplification does not require range switching across the entire measurement range, thus providing good continuity of current measurement and making it suitable for applications with rapidly changing currents. However, logarithmic microcurrent amplification is limited in its application to measuring extremely small currents (10⁻⁶ Ω·cm). －9 The required accuracy (below A) is difficult to achieve. Therefore, existing low-light detection technologies struggle to balance a wide measurement range with high precision. Utility Model Content

[0004] The purpose of this invention is to provide a high linearity, wide-range low-light detection circuit and device to achieve wide-range and high-precision detection of low light.

[0005] To solve the above-mentioned technical problems, this utility model provides a high linearity wide-range low-light detection circuit, including a low-light detection sub-circuit, a logarithmic amplification sub-circuit, and a linear amplification sub-circuit;

[0006] The low-light detection sub-circuit converts the measured low-light signal into a logarithmically varying current signal. The logarithmically amplifying sub-circuit converts the logarithmically varying current signal into a linearly varying voltage signal after current-to-voltage conversion and differential amplification. The linearly amplifying sub-circuit adjusts the range of the voltage signal and outputs it. The external circuit or device obtains the optical power of the measured low-light signal based on the output voltage signal.

[0007] According to the above scheme, the low-light detection sub-circuit includes a photodiode PD;

[0008] The logarithmic amplifier sub-circuit includes: a signal processing module and a bias module;

[0009] The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2.

[0010] The bias module provides bias voltage to the signal processing module.

[0011] According to the above scheme, the linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12; the non-inverting input terminal of operational amplifier U2B is connected to voltage signal VBE1 through resistor R6, the inverting input terminal of operational amplifier U2B is connected to voltage signal VBE2 through resistor R7, the output terminal of operational amplifier U2B outputs the adjusted voltage signal, and the two ends of resistor R12 are connected to the inverting input terminal and the output terminal of operational amplifier U2B, respectively.

[0012] According to the above scheme, it includes a bias sub-circuit, which provides a bias voltage for the linear amplifier sub-circuit; the bias sub-circuit includes resistors R8, R9, R10, and R11; the non-inverting input terminal of operational amplifier U2B is connected to the reference voltage REF through resistor R9, the inverting input terminal of operational amplifier U2B is grounded through resistor R10, the two ends of resistor R10 are grounded and connected to the inverting input terminal of operational amplifier U2B respectively, and the two ends of resistor R11 are grounded and connected to the non-inverting input terminal of operational amplifier U2B respectively.

[0013] According to the above scheme, it includes a slope control sub-circuit, which controls the detection accuracy of the output voltage signal relative to the measured micro-light signal; the slope control sub-circuit includes a resistor R13, with the two ends of the resistor R13 connected to ground and the output terminal of the operational amplifier U2B, respectively.

[0014] This utility model also provides a high linearity wide-range low-light detection device, including the high linearity wide-range low-light detection circuit described above.

[0015] According to the above scheme, the low-light detection sub-circuit includes a photodiode PD;

[0016] The logarithmic amplifier sub-circuit includes: a signal processing module and a bias module;

[0017] The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2.

[0018] The bias module provides bias voltage to the signal processing module.

[0019] According to the above scheme, the linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12; the non-inverting input terminal of operational amplifier U2B is connected to voltage signal VBE1 through resistor R6, the inverting input terminal of operational amplifier U2B is connected to voltage signal VBE2 through resistor R7, the output terminal of operational amplifier U2B outputs the adjusted voltage signal, and the two ends of resistor R12 are connected to the inverting input terminal and the output terminal of operational amplifier U2B, respectively.

[0020] According to the above scheme, it includes a bias sub-circuit, which provides a bias voltage for the linear amplifier sub-circuit; the bias sub-circuit includes resistors R8, R9, R10, and R11; the non-inverting input terminal of operational amplifier U2B is connected to the reference voltage REF through resistor R9, the inverting input terminal of operational amplifier U2B is grounded through resistor R10, the two ends of resistor R10 are grounded and connected to the inverting input terminal of operational amplifier U2B respectively, and the two ends of resistor R11 are grounded and connected to the non-inverting input terminal of operational amplifier U2B respectively.

[0021] According to the above scheme, it includes a slope control sub-circuit, which controls the detection accuracy of the output voltage signal relative to the measured micro-light signal; the slope control sub-circuit includes a resistor R13, with the two ends of the resistor R13 connected to ground and the output terminal of the operational amplifier U2B, respectively.

[0022] Beneficial effects

[0023] This invention utilizes a logarithmic amplifier sub-circuit to convert a current signal into a linearly varying voltage signal, enabling wide-range low-light detection. A linear amplifier sub-circuit is used to adjust the voltage signal output from the logarithmic amplifier sub-circuit to a suitable range, facilitating subsequent processing. By combining the logarithmic and linear amplifier sub-circuits, both detection accuracy and detection range are balanced.

[0024] Furthermore, by setting up a bias sub-circuit to provide a suitable bias voltage to the linear amplifier sub-circuit, the offset caused by the reference current source connected in the logarithmic amplifier sub-circuit can be offset, thereby improving the dynamic range and detection accuracy.

[0025] Furthermore, by changing the resistance value of the slope control sub-circuit, the slope coefficient is altered, thereby changing the ratio of the output voltage to the optical power of the measured micro-light, thus achieving a change in detection accuracy. By combining the selection of the slope coefficient and the amplification factor of the linear amplification sub-circuit, comprehensive control of the measurement range and measurement accuracy is achieved. Attached Figure Description

[0026] Figure 1 This is a structural block diagram of the first high linearity wide-range low-light detection circuit of Embodiment 1 of this utility model;

[0027] Figure 2This is a structural block diagram of the second high linearity wide-range low-light detection circuit in Embodiment 1 of this utility model;

[0028] Figure 3 This is a circuit diagram of the high linearity wide-range low-light detection circuit of Embodiment 1 of this utility model;

[0029] Figure 4 This is a test result diagram of the high linearity wide-range low-light detection circuit of Embodiment 1 of this utility model. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0031] See Figures 1-3 This utility model discloses a high linearity wide-range low-light detection circuit, including a low-light detection sub-circuit (corresponding to...). Figure 1 N1), logarithmic amplifier sub-circuit (corresponding to) Figure 1 (N2), linear amplifier sub-circuit (corresponding to) Figure 1 Medium N4);

[0032] The low-light detection sub-circuit converts the measured low-light signal into a logarithmically varying current signal. The logarithmically amplified current signal is then converted into a linearly varying voltage signal after current-to-voltage conversion and differential amplification. The linear amplification sub-circuit adjusts the range of the voltage signal and outputs it. The external circuit or device obtains the optical power of the measured low-light signal based on the output voltage signal.

[0033] Furthermore, the low-light detection sub-circuit includes a photodiode (PD);

[0034] The logarithmic amplifier sub-circuit includes: a signal processing module and a bias module;

[0035] The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2.

[0036] The bias module provides bias voltage to the signal processing module;

[0037] Specifically, the logarithmic amplifier sub-circuit includes operational amplifier U1A, operational amplifier U2A, operational amplifier U1B, resistors R1, R2, R3, R4, and R5, capacitors C1, C2, and C3, transistors Q1, Q2, and Q3, and Zener diodes D2 and D3.

[0038] Among them, operational amplifier U1A, operational amplifier U2A, resistor R2, resistor R3, capacitor C3, transistor Q2, and transistor Q3 belong to the signal processing module; Zener diode D2, Zener diode D3, resistor R4, resistor R5, and capacitor C3 belong to the bias module; transistor Q1 provides bias voltage for photodiode PD.

[0039] The specific connection relationships of the components in the logarithmic amplifier sub-circuit are as follows:

[0040] The positive terminal of the photodiode PD is connected to ground after passing through resistor R1 and capacitor C1 in sequence, and the negative terminal of the photodiode PD is connected to the output terminal of operational amplifier U1B.

[0041] The positive terminal of Zener diode D2 is grounded, and the negative terminal of Zener diode D2 is connected to the power supply VCC through resistor R4.

[0042] The positive terminal of Zener diode D3 is grounded, and the negative terminal of Zener diode D3 is connected to the power supply VCC through resistor R5. Zener diode D3 is connected in parallel with capacitor C3.

[0043] The output of operational amplifier U1B is connected to the inverting input of operational amplifier U1B through resistor R3, and the inverting input of operational amplifier U1B is connected to the collector of transistor Q1.

[0044] The non-inverting input of operational amplifier U1A is connected to the positive terminal of photodiode PD. The inverting input of operational amplifier U1A is grounded after passing through resistor R2 and capacitor C3 in sequence. The output of operational amplifier U1A is connected to the base of transistor Q2 and the base of transistor Q1 respectively.

[0045] The non-inverting input of operational amplifier U2A is connected to the reference current source IREF, the inverting input of operational amplifier U2A is connected to the inverting input of operational amplifier U1A, and the output of operational amplifier U2A is connected to the base of transistor Q3.

[0046] The emitters of transistors Q1, Q2, and Q3 are all grounded. The collector of transistor Q2 is connected to the positive terminal of photodiode PD, and the collector of transistor Q3 is connected to the reference current source IREF.

[0047] The operational amplifiers U1A and U2A output the converted voltage signals VBE1 and VBE2, respectively.

[0048] Furthermore, the linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12; the non-inverting input of operational amplifier U2B is connected to voltage signal VBE1 via resistor R6, the inverting input of operational amplifier U2B is connected to voltage signal VBE2 via resistor R7, the output of operational amplifier U2B outputs the regulated voltage signal, and the two ends of resistor R12 are connected to the inverting input and output of operational amplifier U2B respectively; the linear amplifier sub-circuit performs approximate differential amplification on voltage signals VBE1 and VBE2.

[0049] Furthermore, it includes a bias sub-circuit (corresponding to) Figure 1 The bias sub-circuit (N3) provides a bias voltage for the linear amplifier sub-circuit. The bias sub-circuit includes resistors R8, R9, R10, and R11. The non-inverting input of operational amplifier U2B is connected to the reference voltage REF via resistor R9, and the inverting input of operational amplifier U2B is grounded via resistor R10. Resistor R10 is connected to ground and the inverting input of operational amplifier U2B, respectively. Resistor R11 is connected to ground and the non-inverting input of operational amplifier U2B, respectively. The bias sub-circuit sets a suitable bias voltage for the subsequent operational amplifier inputs through the reference voltage REF and the voltage division of each resistor.

[0050] Furthermore, it includes a slope control sub-circuit (corresponding to) Figure 1 The slope control sub-circuit controls the detection accuracy of the output voltage signal relative to the measured micro-light signal (N5). The slope control sub-circuit includes a resistor R13, with its two ends grounded and connected to the output of the operational amplifier U2B, respectively.

[0051] The principle of this circuit is as follows.

[0052] Low-light detection is represented as:

[0053] (1)

[0054] In the above formula, I is the output current signal of the photodiode PD. This represents the optical power to current conversion coefficient of the photodiode PD, where P is the input optical power of the photodiode PD.

[0055] The output voltage signal of the logarithmic amplifier subcircuit and the slope control subcircuit is expressed as follows:

[0056] (2)

[0057] (3)

[0058] In the above formula, , The voltage signals VBE1 and VBE2 are represented, and k is the slope coefficient of the slope control sub-circuit (the slope coefficient has a linear relationship with the resistance value of resistor R13, and the larger the resistance of R13, the larger the slope coefficient). This represents the current value of the reference current source IREF. This represents the reverse saturation current of the transistor in the logarithmic amplifier sub-circuit (which is usually very small and varies with external parameters such as temperature).

[0059] According to equations (2) and (3), we get:

[0060] (4)

[0061] As can be seen from equation (4), the difference obtained through processing It can be symmetrically canceled out. The processing accuracy is mainly determined by the reference current source IREF due to errors introduced by external parameters; and the above equation satisfies: , where K is the Boltzmann constant, T is the absolute temperature value, and q is the charge constant.

[0062] The decibel-milliwatt calculation is as follows:

[0063] (5)

[0064] Make equation (5) =1, then the above expression can be simplified to:

[0065] (6)

[0066] In the formula, dBm is decibel milliwatt, and Pm is the optical power per milliwatt.

[0067] Substituting equation (6) into equation (4), we get:

[0068] (7)

[0069] If k and If the value is constant, then differentiating equation (7) yields:

[0070] (8)

[0071] As can be seen from equation (7), the detection accuracy is directly proportional to the slope coefficient. Therefore, in order to improve the detection accuracy, the slope coefficient k can be increased.

[0072] The output of the linear amplifier sub-circuit is expressed as:

[0073] (9)

[0074] In the above formula, This represents the amplification factor of the linear amplifier sub-circuit; it can be seen from the formula that the static quantity... The introduction of static quantity will affect the selection of the amplification factor, and thus affect the measurement range and accuracy. Therefore, this embodiment introduces a bias sub-circuit to cancel the static quantity. The offset. Increase the magnification to improve the measurement range and accuracy.

[0075] The test results of the high linearity wide-range low-light detection circuit in this embodiment can be found in [reference needed]. Figure 4 And the table below.

[0076]

[0077] The table above shows the photocurrent at 100 pA (10 －10 A) ~1uA (10 －6 A) Measured data, Figure 4 The median coordinate plot is the linear fit result of the measured data, which is achieved by fitting a linear function and the linearity is... This indicates a high degree of linearity.

[0078] Example 2:

[0079] This embodiment is basically the same as the first embodiment in principle. Based on the first embodiment, a high linearity wide-range low-light detection device is provided. The device is equipped with the high linearity wide-range low-light detection circuit described in the first embodiment. The high linearity wide-range low-light detection circuit includes a low-light detection sub-circuit, a logarithmic amplification sub-circuit, and a linear amplification sub-circuit.

[0080] The low-light detection sub-circuit converts the measured low-light signal into a logarithmically varying current signal. The logarithmically amplifying sub-circuit converts the logarithmically varying current signal into a linearly varying voltage signal after current-to-voltage conversion and differential amplification. The linearly amplifying sub-circuit adjusts the range of the voltage signal and outputs it. The external circuit or device obtains the optical power of the measured low-light signal based on the output voltage signal.

[0081] Furthermore, the low-light detection sub-circuit includes a photodiode (PD); the logarithmic amplification sub-circuit includes a signal processing module and a bias module.

[0082] The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2.

[0083] The bias module provides bias voltage to the signal processing module;

[0084] Specifically, the logarithmic amplifier sub-circuit includes operational amplifier U1A, operational amplifier U2A, operational amplifier U1B, resistors R1, R2, R3, R4, R5, capacitors C1, C2, C3, transistor Q1 (transistor Q1 provides bias voltage for photodiode PD), transistor Q2, transistor Q3, Zener diode D2, and Zener diode D3;

[0085] Among them, operational amplifier U1A, operational amplifier U2A, resistor R2, resistor R3, capacitor C3, transistor Q2, and transistor Q3 belong to the signal processing module; Zener diode D2, Zener diode D3, resistor R4, resistor R5, and capacitor C3 belong to the bias module; transistor Q1 provides bias voltage for photodiode PD.

[0086] The specific connection relationships of the components in the logarithmic amplifier sub-circuit are as follows:

[0087] The positive terminal of the photodiode PD is connected to ground after passing through resistor R1 and capacitor C1 in sequence, and the negative terminal of the photodiode PD is connected to the output terminal of operational amplifier U1B.

[0088] The positive terminal of Zener diode D2 is grounded, and the negative terminal of Zener diode D2 is connected to the power supply VCC through resistor R4.

[0089] The positive terminal of Zener diode D3 is grounded, and the negative terminal of Zener diode D3 is connected to the power supply VCC through resistor R5. Zener diode D3 is connected in parallel with capacitor C3.

[0090] The output of operational amplifier U1B is connected to the inverting input of operational amplifier U1B through resistor R3, and the inverting input of operational amplifier U1B is connected to the collector of transistor Q1.

[0091] The non-inverting input of operational amplifier U1A is connected to the positive terminal of photodiode PD. The inverting input of operational amplifier U1A is grounded after passing through resistor R2 and capacitor C3 in sequence. The output of operational amplifier U1A is connected to the base of transistor Q2 and the base of transistor Q1 respectively.

[0092] The non-inverting input of operational amplifier U2A is connected to the reference current source IREF, the inverting input of operational amplifier U2A is connected to the inverting input of operational amplifier U1A, and the output of operational amplifier U2A is connected to the base of transistor Q3.

[0093] The emitters of transistors Q1, Q2, and Q3 are all grounded. The collector of transistor Q2 is connected to the positive terminal of photodiode PD, and the collector of transistor Q3 is connected to the reference current source IREF.

[0094] The operational amplifiers U1A and U2A output the converted voltage signals VBE1 and VBE2, respectively.

[0095] Furthermore, the linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12; the non-inverting input terminal of operational amplifier U2B is connected to voltage signal VBE1 through resistor R6, the inverting input terminal of operational amplifier U2B is connected to voltage signal VBE2 through resistor R7, the output terminal of operational amplifier U2B outputs the regulated voltage signal, and the two ends of resistor R12 are connected to the inverting input terminal and the output terminal of operational amplifier U2B, respectively.

[0096] Furthermore, it includes a bias sub-circuit that provides a bias voltage for the linear amplifier sub-circuit; the bias sub-circuit includes resistors R8, R9, R10, and R11; the non-inverting input of operational amplifier U2B is connected to the reference voltage REF through resistor R9, the inverting input of operational amplifier U2B is grounded through resistor R10, the two ends of resistor R10 are grounded and connected to the inverting input of operational amplifier U2B respectively, and the two ends of resistor R11 are grounded and connected to the non-inverting input of operational amplifier U2B respectively.

[0097] Furthermore, it includes a slope control sub-circuit, which controls the detection accuracy of the output voltage signal relative to the measured micro-light signal; the slope control sub-circuit includes a resistor R13, with its two ends grounded and connected to the output terminal of the operational amplifier U2B, respectively.

[0098] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this utility model.

[0099] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A high linearity, wide-range low-light detection circuit, characterized in that, This includes a low-light detection sub-circuit, a logarithmic amplification sub-circuit, and a linear amplification sub-circuit; The low-light detection sub-circuit converts the measured low-light signal into a logarithmically varying current signal. The logarithmically amplifying sub-circuit converts the logarithmically varying current signal into a linearly varying voltage signal after current-to-voltage conversion and differential amplification. The linearly amplifying sub-circuit adjusts the range of the voltage signal and outputs it. The external circuit or device obtains the optical power of the measured low-light signal based on the output voltage signal.

2. The high linearity wide-range low-light detection circuit according to claim 1, characterized in that, The low-light detection sub-circuit includes a photodiode (PD); The logarithmic amplifier sub-circuit includes: a signal processing module and a bias module; The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2. The bias module provides bias voltage to the signal processing module.

3. The high linearity wide-range low-light detection circuit according to claim 2, characterized in that, The linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12. The non-inverting input of operational amplifier U2B is connected to voltage signal VBE1 through resistor R6, and the inverting input of operational amplifier U2B is connected to voltage signal VBE2 through resistor R7. The output of operational amplifier U2B outputs the regulated voltage signal. The two ends of resistor R12 are connected to the inverting input and output of operational amplifier U2B, respectively.

4. The high linearity wide-range low-light detection circuit according to claim 3, characterized in that, It includes a bias sub-circuit, which provides a bias voltage for the linear amplifier sub-circuit; the bias sub-circuit includes resistors R8, R9, R10, and R11; the non-inverting input of operational amplifier U2B is connected to the reference voltage REF through resistor R9, the inverting input of operational amplifier U2B is grounded through resistor R10, the two ends of resistor R10 are grounded and connected to the inverting input of operational amplifier U2B respectively, and the two ends of resistor R11 are grounded and connected to the non-inverting input of operational amplifier U2B respectively.

5. The high linearity wide-range low-light detection circuit according to claim 3, characterized in that, It includes a slope control sub-circuit, which controls the detection accuracy of the output voltage signal relative to the measured micro-light signal; the slope control sub-circuit includes a resistor R13, with its two ends grounded and connected to the output terminal of the operational amplifier U2B, respectively.

6. A high linearity, wide-range low-light detection device, characterized in that, It includes the high linearity wide-range low-light detection circuit as described in claim 1.

7. The high linearity wide-range low-light detection device according to claim 6, characterized in that, The low-light detection sub-circuit includes a photodiode (PD); The logarithmic amplifier sub-circuit includes: a signal processing module and a bias module; The signal processing module includes operational amplifiers U1A, U1B, and U2A. Operational amplifier U1B provides a bias voltage for the low-light detection sub-circuit. Operational amplifiers U1A and U2A are differentially connected. Operational amplifiers U1A and U2A perform differential processing based on the current signal output from the low-light detection sub-circuit and the introduced reference current IREF to obtain two linearly converted voltage signals VBE1 and VBE2. The bias module provides bias voltage to the signal processing module.

8. The high linearity wide-range low-light detection device according to claim 7, characterized in that, The linear amplifier sub-circuit includes operational amplifier U2B, resistors R6, R7, and R12. The non-inverting input of operational amplifier U2B is connected to voltage signal VBE1 through resistor R6, and the inverting input of operational amplifier U2B is connected to voltage signal VBE2 through resistor R7. The output of operational amplifier U2B outputs the regulated voltage signal. The two ends of resistor R12 are connected to the inverting input and output of operational amplifier U2B, respectively.

9. The high linearity wide-range low-light detection device according to claim 8, characterized in that, It includes a bias sub-circuit, which provides a bias voltage for the linear amplifier sub-circuit; the bias sub-circuit includes resistors R8, R9, R10, and R11; the non-inverting input of operational amplifier U2B is connected to the reference voltage REF through resistor R9, the inverting input of operational amplifier U2B is grounded through resistor R10, the two ends of resistor R10 are grounded and connected to the inverting input of operational amplifier U2B respectively, and the two ends of resistor R11 are grounded and connected to the non-inverting input of operational amplifier U2B respectively.

10. The high linearity wide-range low-light detection device according to claim 8, characterized in that, It includes a slope control sub-circuit, which controls the detection accuracy of the output voltage signal relative to the measured micro-light signal; the slope control sub-circuit includes a resistor R13, with its two ends grounded and connected to the output terminal of the operational amplifier U2B, respectively.

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