Self-adaptive bias voltage adjusting circuit of refrigeration detector

Abstract

The utility model relates to the field of infrared detectors, in particular to a bias voltage self-adaptive adjusting circuit of a refrigeration detector. Comprising an environment temperature acquisition circuit, a fine tuning signal acquisition circuit, a master control circuit and a bias voltage adjusting circuit, the environment temperature acquisition circuit and the fine tuning signal acquisition circuit are respectively connected with the input end of the master control circuit, and the output end of the master control circuit is connected with the bias voltage adjusting circuit; the environment temperature collecting circuit and the fine tuning signal collecting circuit collect environment temperature and imaging signals of a detector respectively and transmit the environment temperature and the imaging signals to the main control circuit, and the main control circuit generates bias voltage adjusting information according to the difference value of the environment temperature and the imaging signals and sends the bias voltage adjusting information to the bias voltage adjusting circuit. The bias adjustment circuit adjusts the bias voltage according to the bias voltage adjustment information. The bias voltage of the detector can be conveniently and quickly adjusted, and the influence of the environment on output data of the detector is reduced.

Description

Technical Field

[0001] The utility model relates to the field of infrared detectors, in particular to a cooling detector bias voltage self-adaptive adjustment circuit. Background Art

[0002] A cooled detector primarily consists of a focal plane detector chip, a CMOS readout circuit, a refrigerator, a dewar structure, and an infrared window. The ability of a cooled detector to produce sufficiently clear images depends on the CMOS readout circuit processing the data from the focal plane detector chip. Bias voltage is a crucial component of this process. This bias voltage is primarily determined by the operating temperature of the sensor. This temperature range can be broadly categorized into three ranges: low temperature (-30°C to -5°C), ambient temperature (10°C to 45°C), and high temperature (50°C to 65°C). The bias voltage varies significantly in these ranges.

[0003] Currently, adjusting the bias voltage of the detector requires the coordinated adjustment of multiple devices such as a voltage-stabilized power supply, a display, a computer, a debugging circuit, a voltmeter, etc., which takes a lot of time. Utility Model Content

[0004] In response to the defects of the existing technology, the utility model provides a cooling detector bias voltage adaptive adjustment circuit, which adaptively adjusts the bias voltage based on the temperature and the real-time value of the bias voltage, can output data signals stably and efficiently, and realize the normal operation of the detector.

[0005] In order to solve the technical problem, the technical solution adopted by the present invention is: a cooling detector bias voltage adaptive adjustment circuit, including an ambient temperature acquisition circuit, a fine-tuning signal acquisition circuit, a main control circuit and a bias voltage adjustment circuit, the ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit are respectively connected to the input end of the main control circuit, and the output end of the main control circuit is connected to the bias voltage adjustment circuit; the ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit respectively collect the ambient temperature and the imaging signal of the detector, and transmit the collected ambient temperature and imaging signal differential value to the main control circuit, the main control circuit generates bias voltage adjustment information according to the ambient temperature and imaging signal differential value, and sends the bias voltage adjustment information to the bias voltage adjustment circuit, and the bias voltage adjustment circuit adjusts the bias voltage according to the bias voltage adjustment information.

[0006] Furthermore, the bias voltage adjustment circuit includes a digital potentiometer N1 and an amplifier N2. The I2C interfaces SCL and SDA of the digital potentiometer N1 are connected to the output end of the main control circuit. The sliding end of the digital potentiometer is connected to the non-inverting input end of the amplifier N2 through a resistor R90. The inverting input end of the amplifier N2 is connected to its output end through a resistor R92. The power supply end of the amplifier N2 is connected to the power supply. The output end of the amplifier N2 outputs the adjusted bias voltage through a resistor R93.

[0007] Furthermore, the high resistance end of the digital potentiometer N1 is connected to the power supply through the resistor R86, the low resistance end of the digital potentiometer N1 is grounded through the resistor R88, a resistor R87 is provided between the power supply and the resistor R90, and a resistor R89, a capacitor C82, and a capacitor C83 are provided in parallel between the resistor R90 and the ground.

[0008] Furthermore, the fine-tuning signal acquisition circuit includes an amplifier N3B and a differential chip U3. The imaging signal of the detector is transmitted to the positive phase input terminal of the amplifier N3B through the resistor R98. The negative phase input terminal of the amplifier N3B is connected to its output terminal through the resistor R94. The output terminal of the amplifier N3B is connected to the negative phase input terminal of the differential chip U3 through the resistors R96 and R97. The standard voltage VREF is connected to the positive phase input terminal of the differential chip U3 through the resistors R0402 and R95. The differential signal op amp common mode reference is connected to the Vcom terminal of the differential chip U3. The positive phase output terminal and the negative phase output terminal of the differential chip U3 respectively output the imaging signal differential value to the main control chip through the resistors.

[0009] Furthermore, the resistor R98 and the non-inverting input terminal of the amplifier N3B are grounded through the capacitor C88, the resistor R96 and the resistor R97 are grounded through the capacitor C87, the resistor R100 is connected between the inverting input terminal and the non-inverting output terminal of the differential chip U3, the differential signal op amp common mode reference and the Vcom terminal of the differential chip U3 are grounded through the capacitor C90, the resistor R0402 and the resistor R95 are grounded through the capacitor C89, and the resistor R101 is connected between the non-inverting input terminal and the non-inverting output terminal of the differential chip U3.

[0010] Furthermore, the fine-tuning signal acquisition circuit has multiple channels, and each channel collects the imaging signal of the detector.

[0011] Furthermore, the ambient temperature acquisition circuit includes a temperature sensor and a transistor Q2. The temperature sensor adopts DS18B20, and its pin 1 DQ and pin 2 GND are connected to the negative temperature output terminal through resistors R8 and R9 respectively. The power supply VCC is connected to the base of the transistor Q2 through resistor R10. The power supply VCC is connected to the collector of the transistor Q2. The emitter of the transistor Q2 is connected to the positive temperature output terminal. A resistor R7 is connected between the positive temperature output terminal and the negative temperature output terminal, and the positive temperature output terminal and the negative temperature output terminal are respectively connected to the input terminal of the main control circuit.

[0012] The beneficial effects of the present invention are as follows: the present invention includes an ambient temperature acquisition circuit, a fine-tuning signal acquisition circuit, a bias voltage adjustment circuit and a main control circuit. The main control circuit determines the bias voltage of the detector according to the ambient temperature, and then adjusts the bias voltage according to the difference between the multi-channel signal transmission of the detector and the standard value to make it reach a normal state. It can output data signals stably and efficiently to realize the normal operation of the detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a principle block diagram of the utility model;

[0014] Figure 2 This is the schematic diagram of the main control circuit;

[0015] Figure 3 This is the schematic diagram of the bias voltage adjustment circuit;

[0016] Figure 4 Schematic diagram for fine-tuning the signal acquisition circuit;

[0017] Figure 5 This is the schematic diagram of the ambient temperature acquisition circuit. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0019] Example 1

[0020] This embodiment discloses a cooling detector bias voltage adaptive adjustment circuit. Figure 1As shown, it includes an ambient temperature acquisition circuit, a fine-tuning signal acquisition circuit, a main control circuit and a bias voltage adjustment circuit. The ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit are respectively connected to the input end of the main control circuit, and the output end of the main control circuit is connected to the bias voltage adjustment circuit; the ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit respectively acquire the ambient temperature and the imaging signal of the detector, and transmit the acquired differential value of the ambient temperature and the imaging signal to the main control circuit. The main control circuit generates bias voltage adjustment information according to the differential value of the ambient temperature and the imaging signal, and sends the bias voltage adjustment information to the bias voltage adjustment circuit. The bias voltage adjustment circuit adjusts the bias voltage according to the bias voltage adjustment information.

[0021] like Figure 2 As shown in the figure, the main control circuit is implemented based on the STM32 microcontroller. The main control circuit has 6 pins leading outward, namely the SDA and SCL pins (output ends) connected to the bias voltage adjustment circuit, the LINE IN+ and LINE IN- (input ends) connected to the ambient temperature acquisition circuit, and the VSIGN2+ and VSIGN2- (input ends) connected to the fine-tuning signal acquisition circuit. Figure 2 Only the used pins are shown; unused pins are not. The main control circuit receives ambient temperature data from the ambient temperature acquisition circuit, identifies it, and adjusts the bias voltage output by the bias voltage adjustment circuit in real time. The signal acquisition circuit then compares the detector signal and sends it as a differential signal to the main control circuit, which then determines whether further bias voltage adjustment is necessary.

[0022] like Figure 3 As shown, the bias voltage adjustment circuit includes a digital potentiometer N1 and an amplifier N2. The I2C interfaces SCL and SDA of digital potentiometer N1 are connected to the output of the main control circuit. The slider of the digital potentiometer is connected to the non-inverting input of amplifier N2 via resistor R90. The inverting input of amplifier N2 is connected to its output via resistor R92. The power supply terminal of amplifier N2 is connected to a power supply, and the output of amplifier N2 outputs the adjusted bias voltage via resistor R93. The high-resistance terminal of digital potentiometer N1 is connected to the power supply via resistor R86, and the low-resistance terminal of digital potentiometer N1 is connected to ground via resistor R88. Resistor R87 is provided between the power supply and resistor R90. Resistor R89, capacitor C82, and capacitor C83 are connected in parallel between resistor R90 and ground.

[0023] The bias voltage adjustment circuit is mainly controlled by the main control circuit, receives the electrical signal from the main control circuit, and adjusts the bias voltage generated by it. It has the advantages of fast speed, high precision and low energy consumption, and can automatically save the bias voltage required under the current ambient temperature.

[0024] The main control circuit changes the electrical signal sent by the electronic potentiometer through the SCL and SDA signals, and outputs the voltage through the amplifier N2 to change the GPOL value.

[0025] like Figure 4 As shown, the fine-tuning signal acquisition circuit includes an amplifier N3B and a differential chip U3. The imaging signal of the detector is transmitted to the positive phase input terminal of the amplifier N3B through the resistor R98. The negative phase input terminal of the amplifier N3B is connected to its output terminal through the resistor R94. The output terminal of the amplifier N3B is connected to the negative phase input terminal of the differential chip U3 through the resistors R96 and R97. The standard voltage VREF is connected to the positive phase input terminal of the differential chip U3 through the resistors R0402 and R95. The differential signal operational amplifier common mode reference is connected to the Vcom terminal of the differential chip U3. The positive phase output terminal and the negative phase output terminal of the differential chip U3 respectively output the imaging signal differential value to the main control chip through the resistors. In order to make the signal more stable, filtering elements are added. For example, the resistor R98 is connected to the positive input terminal of the amplifier N3B through the capacitor C88, the resistor R96 and the resistor R97 are connected to the ground through the capacitor C87, the resistor R100 is connected between the inverting input terminal and the positive output terminal of the differential chip U3, the differential signal op amp common mode reference and the Vcom terminal of the differential chip U3 are grounded through the capacitor C90, the resistor R0402 and the resistor R95 are grounded through the capacitor C89, and the resistor R101 is connected between the positive input terminal and the inverting output terminal of the differential chip U3.

[0026] In this embodiment, the fine-tuning signal acquisition circuit has multiple channels, each of which collects the detector imaging signal. As the core of the detector chip data acquisition, the multi-channel signal acquisition circuit is affected by the bias voltage adjustment circuit and needs to send the collected data to the main control circuit for judgment. Figure 4 This is a single-channel signal acquisition circuit. Information enters the signal collector from pin 5 of N3B, is processed, and then fed into the differential chip. The differential chip then outputs a differential signal to the main control circuit. The main control circuit analyzes the information and sends the information to the bias voltage adjustment circuit to change the GOPL value. VREF is the standard input terminal. VCOM is the differential signal op amp common mode reference.

[0027] like Figure 5As shown, the ambient temperature acquisition circuit includes a temperature sensor and transistor Q2. The temperature sensor uses a DS18B20. Pin 1 (DQ) and pin 2 (GND) are connected to the negative temperature output terminal via resistors R8 and R9, respectively. Power supply VCC is connected to the base of transistor Q2 via resistor R10. Power supply VCC is connected to the collector of transistor Q2, and the emitter of transistor Q2 is connected to the positive temperature output terminal. Resistor R7 is connected between the positive and negative temperature output terminals. Both the positive and negative temperature output terminals are connected to the input terminals of the main control circuit. The ambient temperature acquisition circuit monitors the real-time temperature of the detector's environment and transmits it to the main control circuit. It features high precision and low energy consumption.

[0028] The utility model discloses a bias voltage automatic adjustment circuit based on a refrigeration detector, which can adjust the detector bias voltage conveniently and quickly, and reduce the influence of the environment on the detector output data.

[0029] The above description is only the basic principle and preferred embodiments of the present invention. Improvements and substitutions made by those skilled in the art based on the present invention fall within the scope of protection of the present invention.

Claims

1. A cooling detector bias voltage adaptive adjustment circuit, characterized by: It includes an ambient temperature acquisition circuit, a fine-tuning signal acquisition circuit, a main control circuit and a bias voltage adjustment circuit. The ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit are respectively connected to the input end of the main control circuit, and the output end of the main control circuit is connected to the bias voltage adjustment circuit; the ambient temperature acquisition circuit and the fine-tuning signal acquisition circuit respectively acquire the ambient temperature and the imaging signal of the detector, and transmit the acquired differential value of the ambient temperature and the imaging signal to the main control circuit. The main control circuit generates bias voltage adjustment information according to the differential value of the ambient temperature and the imaging signal, and sends the bias voltage adjustment information to the bias voltage adjustment circuit. The bias voltage adjustment circuit adjusts the bias voltage according to the bias voltage adjustment information and transmits it to the detector.

2. The cooling detector bias voltage adaptive adjustment circuit according to claim 1, characterized in that: The bias voltage adjustment circuit includes a digital potentiometer N1 and an amplifier N2. The I2C interfaces SCL and SDA of the digital potentiometer N1 are connected to the output of the main control circuit. The sliding end of the digital potentiometer N1 is connected to the non-inverting input end of the amplifier N2 through a resistor R90. The inverting input end of the amplifier N2 is connected to its output end through a resistor R92. The power supply end of the amplifier N2 is connected to the power supply. The output end of the amplifier N2 outputs the adjusted bias voltage through a resistor R93.

3. The cooling detector bias voltage adaptive adjustment circuit according to claim 2, characterized in that: The high resistance end of the digital potentiometer N1 is connected to the power supply through the resistor R86, and the low resistance end of the digital potentiometer N1 is grounded through the resistor R88. A resistor R87 is provided between the power supply and the resistor R90, and a resistor R89, a capacitor C82, and a capacitor C83 are provided in parallel between the resistor R90 and the ground.

4. The cooling detector bias voltage adaptive adjustment circuit according to claim 1, characterized in that: The fine-tuning signal acquisition circuit includes an amplifier N3B and a differential chip U3. The imaging signal of the detector is transmitted to the positive-phase input terminal of the amplifier N3B through a resistor R98. The negative-phase input terminal of the amplifier N3B is connected to its output terminal through a resistor R94. The output terminal of the amplifier N3B is connected to the negative-phase input terminal of the differential chip U3 through resistors R96 and R97. The standard voltage VREF is connected to the positive-phase input terminal of the differential chip U3 through resistors R0402 and R95. The common-mode reference of the differential signal op amp is connected to the Vcom terminal of the differential chip U3. The positive-phase output terminal and the negative-phase output terminal of the differential chip U3 respectively output the imaging signal differential value to the main control chip through resistors.

5. The cooling detector bias voltage adaptive adjustment circuit according to claim 4, characterized in that: The resistor R98 and the non-inverting input terminal of the amplifier N3B are grounded through the capacitor C88, the resistor R96 and the resistor R97 are grounded through the capacitor C87, the resistor R100 is connected between the inverting input terminal and the non-inverting output terminal of the differential chip U3, the differential signal op amp common mode reference and the Vcom terminal of the differential chip U3 are grounded through the capacitor C90, the resistor R0402 and the resistor R95 are grounded through the capacitor C89, and the resistor R101 is connected between the non-inverting input terminal and the non-inverting output terminal of the differential chip U3.

6. The cooling detector bias voltage adaptive adjustment circuit according to claim 1 or 4, characterized in that: The fine-tuning signal acquisition circuit has multiple channels, and each channel respectively acquires the imaging signal of the detector.

7. The cooling detector bias voltage adaptive adjustment circuit according to claim 1, characterized in that: The ambient temperature acquisition circuit includes a temperature sensor and a transistor Q2. The temperature sensor adopts DS18B20. Its pin 1 DQ and pin 2 GND are connected to the negative temperature output terminal through resistors R8 and R9 respectively. The power supply VCC is connected to the base of the transistor Q2 through resistor R10. The power supply VCC is connected to the collector of the transistor Q2. The emitter of the transistor Q2 is connected to the positive temperature output terminal. A resistor R7 is connected between the positive temperature output terminal and the negative temperature output terminal, and the positive temperature output terminal and the negative temperature output terminal are respectively connected to the input terminal of the main control circuit.

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