A temperature acquisition circuit and acquisition method of an electronic oil pump for vehicle

Abstract

The application discloses a temperature acquisition circuit and method of a vehicle-mounted electronic oil pump, which comprises a plurality of digital potentiometers, a plurality of resistors, a plurality of operational amplifiers, a plurality of flip-flops and a NOT gate. The first pins of digital potentiometers U2 and U3 are connected with a CLK end; the second pins of the digital potentiometers U2 and U3 are connected with the first and seventh pins of a plurality of operational amplifiers U5 respectively; the eighth pins of the digital potentiometers U2 and U3, the twentieth pin of a plurality of flip-flops U4, the fourth pin of the plurality of operational amplifiers U5, the fifth pin of a NOT gate U1 and one end of resistors R5 and R6 are connected with a power supply; the seventh pin of the digital potentiometer U2 is connected with the second and fourth pins of the plurality of flip-flops U4; the seventh pin of the digital potentiometer U3 is connected with the fifth and seventh pins of the plurality of flip-flops U4; the sixth and eighth pins of the plurality of flip-flops U4 are connected with an FB end, and the eleventh pin is connected with a CP end; and the fourth pin of the NOT gate U1 is connected with the first pin of the plurality of flip-flops U4.

Description

Technical Field

[0001] The present invention relates to the technical field of engine control, and in particular to a temperature acquisition circuit and acquisition method for a vehicle-mounted electronic oil pump. Background Art

[0002] The viscosity of the oil changes nonlinearly with temperature, and the change in viscosity directly affects the flow resistance and system pressure of the oil pump. When the oil is at a low temperature and has a high viscosity, the speed needs to be increased to quickly build up the oil pressure to prevent lubrication or oil supply delays. When the oil is at a high temperature and has a low viscosity, the speed needs to be reduced to the required flow rate to avoid energy waste and high-speed cooling. The oil pump speed is adjusted based on the sampling temperature, and the sampling resistor uses different resistance values ​​at different temperatures. To avoid adjustment misalignment, temperature sampling generally adopts partition sampling, that is, a sampling resistor with a different resistance value is set for each temperature interval or two sampling resistors are balanced to avoid adjustment misalignment. However, partition sampling will cause obvious oscillation in the oil pump speed when switching the sampling resistor. This is because the temperature parameters fed back by each partition are different during critical switching. Therefore, a temperature acquisition circuit and acquisition method for an on-board electronic oil pump that can avoid speed oscillation are proposed. Summary of the Invention

[0003] In view of the above technical problems, the purpose of the present invention is to provide a temperature acquisition circuit for an on-vehicle electronic oil pump, comprising a plurality of digital potentiometers, a plurality of resistors, a multi-way operational amplifier, a multi-way trigger, and a NOT gate. The first pins of the digital potentiometers U2 and the digital potentiometer U3 in the plurality of digital potentiometers are connected to the CLK terminal; the second pins of the digital potentiometers U2 and the digital potentiometer U3 are connected to the first and seventh pins of the multi-way operational amplifier U5 respectively; the eighth pins of the digital potentiometers U2 and the digital potentiometer U3, the twentieth pin of the multi-way trigger U4, the fourth pin of the multi-way operational amplifier U5, the fifth pin of the NOT gate U1, the resistor R5, and one end of the resistor R6 are connected to the power supply; the seventh pin of the digital potentiometer U2 is connected to the second and fourth pins of the multi-way trigger U4; the seventh pin of the digital potentiometer U3 is connected to the fifth and seventh pins of the multi-way trigger U4. Seven pins; the sixth and eighth pins of the multi-way trigger U4 are connected to the FB terminal, and the eleventh pin is connected to the CP terminal; the fourth pin of the NOT gate U1 is connected to the first pin of the multi-way trigger U4, and the second pin is connected to the ninth pin of the multi-way trigger U4; the other end of the resistor R5 is connected to the third pin of the digital potentiometer U2 and the third and twelfth pins of the multi-way operational amplifier U5; the other end of the resistor R6 is connected to the third pin of the digital potentiometer U3 and the fifth and tenth pins of the multi-way operational amplifier U5; the second and sixth pins of the multi-way operational amplifier U5 are connected to the RT terminal, the thirteenth and ninth pins are connected to one end of the resistor R7 and the resistor R8 respectively, and the fourteenth and eighth pins are connected to the other end of the resistor R7 and the resistor R8 respectively; the third pin of the NOT gate U1, the fourth, fifth and sixth pins of the digital potentiometer U2 and the digital potentiometer U3, and the eleventh pin of the multi-way operational amplifier U5 are grounded.

[0004] Furthermore, it also includes several operational amplifiers and multiplexers, wherein the third pin of the operational amplifier U7 among the several operational amplifiers is connected to the other end of the resistor R5, the second pin is connected to the other end of the resistor R6, and the first pin is connected to the tenth and eleventh pins of the multiplexer U6; the third pin of the operational amplifier U8 is connected to one end of the resistor R10 and the resistor R11, the second pin is connected to one end of the resistor R9 and the resistor R12, and the first pin is connected to the other end of the resistor R12; the first and twelfth pins of the multiplexer U6 are connected to the other end of the resistor R8, the second and thirteenth pins are connected to the other end of the resistor R7, the fourteenth and fifteenth pins are respectively connected to the other end of the resistor R10 and the resistor R9, and the sixteenth pin is connected to the power supply; the other end of the resistor R11 and the sixth, seventh and eighth pins of the multiplexer U6 are grounded.

[0005] Furthermore, the second pin of the operational amplifier U9 is connected to the third pin of the operational amplifier U10 and the first pin of the operational amplifier U8, and the first pin is connected to the OUT1 terminal; the first pin of the operational amplifier U10 is connected to the OUT2 terminal.

[0006] Furthermore, one end of the resistor R1 is connected to the seventh pin of the digital potentiometer U2; one end of the resistor R2 is connected to the third pin of the multi-way trigger U4; one end of the resistor R3 is connected to the seventh pin of the digital potentiometer U3; one end of the resistor R4 is connected to the FB terminal; the other ends of the resistors R1, R2, R3 and R4 are grounded.

[0007] Furthermore, one end of the resistor R15 is connected to the power supply, and the tap end and the other end are connected to one end of the resistor R13 and the third pin of the operational amplifier U9; the other end of the resistor R13 is connected to one end of the resistor R14 and the second pin of the operational amplifier U10; the other end of the resistor R14 is grounded.

[0008] Furthermore, the resistor R15 is a sliding resistor.

[0009] Furthermore, a method for collecting the temperature of an on-vehicle electronic oil pump includes the following steps:

[0010] S1. Set up an acquisition circuit and a processor, the acquisition circuit receives the CP signal and samples the RT temperature signal;

[0011] S2. The acquisition circuit feeds back the OUT1 and OUT2 status signals and the FB signal to the processor based on the CP signal input;

[0012] S3. The acquisition circuit takes values ​​of the RT signal at the first and second inputs of the CP signal respectively;

[0013] S4. The acquisition circuit feeds back two RT value signals to the processor when the CP signal is input for the third time. The processor adjusts the RT resistance value based on the positive and negative values ​​and the states of OUT1 and OUT2, and feeds back the fourth CP signal to reset the circuit and then cycle.

[0014] The beneficial effects of the present invention compared with the prior art are:

[0015] The present invention replaces partition sampling with a cyclic detection method, so that the temperature-dependent control sampling is within the optimal accuracy range, avoiding the speed oscillation problem caused by excessive span during temperature sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, a brief introduction is given below to the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a circuit structure diagram provided by the present invention. DETAILED DESCRIPTION

[0018] In order to make the objects and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the embodiments. It should be understood that the following text is only used to describe one or several specific implementation methods of the present invention and does not strictly limit the scope of protection specifically requested by the present invention.

[0019] The present invention discloses a temperature acquisition circuit for an on-vehicle electronic oil pump, comprising a plurality of digital potentiometers, a plurality of resistors, a multi-way operational amplifier, a multi-way trigger, and a NOT gate. The first pins of the digital potentiometers U2 and the digital potentiometer U3 in the plurality of digital potentiometers are connected to the CLK terminal; the second pins of the digital potentiometers U2 and the digital potentiometer U3 are connected to the first and seventh pins of the multi-way operational amplifier U5 respectively; the eighth pins of the digital potentiometers U2 and the digital potentiometer U3, the twentieth pin of the multi-way trigger U4, the fourth pin of the multi-way operational amplifier U5, the fifth pin of the NOT gate U1, the resistor R5, and one end of the resistor R6 are connected to a power supply; the seventh pin of the digital potentiometer U2 is connected to the second and fourth pins of the multi-way trigger U4; the seventh pin of the digital potentiometer U3 is connected to the fifth and seventh pins of the multi-way trigger U4; The sixth and eighth pins of the trigger U4 are connected to the FB terminal, and the eleventh pin is connected to the CP terminal; the fourth pin of the NOT gate U1 is connected to the first pin of the multi-way trigger U4, and the second pin is connected to the ninth pin of the multi-way trigger U4; the other end of the resistor R5 is connected to the third pin of the digital potentiometer U2 and the third and twelfth pins of the multi-way operational amplifier U5; the other end of the resistor R6 is connected to the third pin of the digital potentiometer U3 and the fifth and tenth pins of the multi-way operational amplifier U5; the second and sixth pins of the multi-way operational amplifier U5 are connected to the RT terminal, the thirteenth and ninth pins are connected to one end of the resistor R7 and the resistor R8 respectively, and the fourteenth and eighth pins are connected to the other end of the resistor R7 and the resistor R8 respectively; the third pin of the NOT gate U1, the fourth, fifth and sixth pins of the digital potentiometer U2 and the digital potentiometer U3, and the eleventh pin of the multi-way operational amplifier U5 are grounded.

[0020] Specifically, it also includes several operational amplifiers and multiplexers. The third pin of the operational amplifier U7 among the operational amplifiers is connected to the other end of the resistor R5, the second pin is connected to the other end of the resistor R6, and the first pin is connected to the tenth and eleventh pins of the multiplexer U6; the third pin of the operational amplifier U8 is connected to one end of the resistor R10 and the resistor R11, the second pin is connected to one end of the resistor R9 and the resistor R12, and the first pin is connected to the other end of the resistor R12; the first and twelfth pins of the multiplexer U6 are connected to the other end of the resistor R8, the second and thirteenth pins are connected to the other end of the resistor R7, the fourteenth and fifteenth pins are connected to the other end of the resistor R10 and the resistor R9 respectively, and the sixteenth pin is connected to the power supply; the other end of the resistor R11 and the sixth, seventh and eighth pins of the multiplexer U6 are grounded.

[0021] Specifically, the second pin of the operational amplifier U9 is connected to the third pin of the operational amplifier U10 and the first pin of the operational amplifier U8, and the first pin is connected to the OUT1 terminal; the first pin of the operational amplifier U10 is connected to the OUT2 terminal.

[0022] Specifically, one end of the resistor R1 is connected to the seventh pin of the digital potentiometer U2; one end of the resistor R2 is connected to the third pin of the multi-way trigger U4; one end of the resistor R3 is connected to the seventh pin of the digital potentiometer U3; one end of the resistor R4 is connected to the FB terminal; the other ends of the resistors R1, R2, R3 and R4 are grounded.

[0023] Specifically, one end of the resistor R15 is connected to the power supply, and the tap end and the other end are connected to one end of the resistor R13 and the third pin of the operational amplifier U9; the other end of the resistor R13 is connected to one end of the resistor R14 and the second pin of the operational amplifier U10; the other end of the resistor R14 is grounded.

[0024] Specifically, the resistor R15 is a sliding resistor.

[0025] Specifically, a method for collecting the temperature of an on-vehicle electronic oil pump includes the following steps:

[0026] S1. Set up an acquisition circuit and a processor, the acquisition circuit receives the CP signal and samples the RT temperature signal;

[0027] S2. The acquisition circuit feeds back the OUT1 and OUT2 status signals and the FB signal to the processor based on the CP signal input;

[0028] S3. The acquisition circuit takes values ​​of the RT signal at the first and second inputs of the CP signal respectively;

[0029] S4. The acquisition circuit feeds back two RT value signals to the processor when the CP signal is input for the third time. The processor adjusts the RT resistance value based on the positive and negative values ​​and the states of OUT1 and OUT2, and feeds back the fourth CP signal to reset the circuit and then cycle.

[0030] The signal legend in this application illustrates that FB is the sampling signal, and the processor samples the OUT1 and OUT2 status signals when FB is fed back; CP is the control signal, and RT is the temperature feedback signal. When the CP input signal is input for the first time in the circuit, the circuit takes the value of the current RT signal parameter, and takes the value of the RT signal parameter again when the CP input signal is input for the second time, until the third CP input signal is fed back to the processor to sample the OUT1 and OUT2 states. If the RT resistance value remains unchanged when both OUT1 and OUT2 are high, the RT resistance value is increased or decreased when either is low, and then the CP input signal is reset again to wait for the cycle. During the cycle, the RT resistance value is kept within the capture range of optimal accuracy.

[0031] In one embodiment, when the power is initially turned on, the RT signal is fed back to the 6th pin and the 2nd pin of the multi-channel operational amplifier U5 for sampling. At the same time, the 3rd pin of the multi-channel operational amplifier U5 samples the 3rd pin of the digital potentiometer U2 and the voltage at the end of the resistor R5, and the 5th pin of the multi-channel operational amplifier U5 samples the 3rd pin of the digital potentiometer U3 and the voltage at the end of the resistor R6. After the multi-channel operational amplifier U5 makes comparisons, the signals are fed back to the 2nd pin of the digital potentiometer U2 and the digital potentiometer U3 for adjustment. The 3rd pin of the digital potentiometer U2 and the digital potentiometer U3 are compared with the 3rd pin signal of the digital potentiometer U2 and the digital potentiometer U3 according to the corresponding input of the 2nd pin signal of the multi-channel operational amplifier U5. The RT parameter corresponds to and waits for the CP signal input; when the CP signal is input for the first time, the 2-pin of the multi-way trigger U4 outputs a signal, one of which is fed back to the 7-pin of the digital potentiometer U2 for mediation, and the other is fed back to the 4-pin so that the CP does not reset in the subsequent non-corresponding input, and the 3-pin of the digital potentiometer U3 corresponds to the RT parameter in real time; when the CP signal is input for the second time, the 5-pin of the multi-way trigger U4 is output, and the output signal is fed back to the 7-pin of the digital potentiometer U3 for mediation, and the other is fed back to the 7-pin of the multi-way trigger U4 so that the CP does not reset in the subsequent non-corresponding input. No reset is performed; when CP inputs the signal for the third time, the 6th and 8th pins of the multi-way trigger U4 are output, and the 6th pin of the multi-way trigger U4 is input to the processor through FB. At the same time, the 12th and 10th pins of the multi-way operational amplifier U5 respectively sample the 3rd pin of the digital potentiometer U2 and the 3rd pin of the digital potentiometer U3, and follow and isolate the output after the 14th and 8th pin loops connected to the corresponding resistors R7 and R8 and the multi-way operational amplifier U5. In this embodiment, the 14th and 8th pins of the multi-way operational amplifier U5 are respectively input to the processor for detection processing. The detection method of the processor is to receive F B signal, when the voltage parameters of the 14 and 8 pins of the multi-channel operational amplifier U5 are in a positive difference and are less than the preset parameters, the RT resistance value is not increased. When it is in a negative difference, the position of the multi-channel operational amplifier U5 feedback to the processor 14 pin and 8 pin is swapped to maintain a positive difference and is greater than the preset parameters without decreasing the RT resistance. Otherwise, the RT resistance value is increased or decreased. The resistance control of RT can be achieved by increasing or decreasing the loop resistance through a multi-stage resistor in series, or by using a digital potentiometer. When the FB signal is received, the processor feeds back a CS low-level signal to start, and the U / D input signal is realized based on the above-mentioned RT adjustment conditions, which is not shown in the accompanying drawings.

[0032] In one embodiment, another RT sampling scheme is provided based on the above scheme. Compared with the first scheme, the response speed of the entire cycle can be increased by removing the redundant data when the processor detects the RT adjustment condition. Since the outputs of the 14 and 8 pins of the multi-channel operational amplifier U5 will have a negative difference due to the change state of RT, and when the RT is negative, a data bit needs to be added to confirm the swap instruction. This data bit is redundant data when the RT is positive. To ensure that the timing and code bit are consistent each time, a data bit must be added for both states after the RT value is taken. In the scheme, the processor is first removed for The sampling of the multi-channel operational amplifier U5 is fed back to the 2nd and 13th pins of the multiplexer U6, and the 8th pin of the multi-channel operational amplifier U5 is fed back to the 12th and 1st pins of the multiplexer U6 respectively. The 3rd and 2nd pins of the operational amplifier U7 respectively sample the 3rd pin parameters of the digital potentiometer U2 and the digital potentiometer U3 and input them to the 11th pin of the multiplexer U6 after comparison. When the operational amplifier U7 has no output, the 3rd pin parameter of the digital potentiometer U3 is greater than the 3rd pin parameter of the digital potentiometer U2, and the 15th pin of the multiplexer U6 outputs the 1st pin. Parameters, the 14th pin of the demultiplexer U6 outputs the 13th pin parameter, when the operational amplifier U7 outputs, the 3rd pin parameter of the digital potentiometer U3 is smaller than the 3rd pin parameter of the digital potentiometer U2, the 15th pin of the demultiplexer U6 outputs the 2nd pin parameter, the 14th pin of the demultiplexer U6 outputs the 12th pin parameter, the 15th pin of the demultiplexer U6 then forms a positive feedback through the resistor R9, the operational amplifier U8 and the resistor R12, the 14th pin of the demultiplexer U6 is input to the operational amplifier U8 after passing through the resistor R10 and the resistor R11 ground loop, at this time, no matter RT is input twice before CP What state is the RT temperature in when CP inputs? The op amp U8 is in positive difference. The output of op amp U8 is fed back to the processor to reduce the redundant data bits when the positive difference occurs. At this time, the processor only lowers the RT resistance when the output of op amp U8 is greater than the preset parameters, and increases the RT resistance when it is less than the preset parameters. When CP inputs the signal for the fourth time, the 9-pin of the multi-way trigger U4 outputs the signal to the NOT gate U1. The NOT gate U1 inverts and outputs the signal to the 1-pin of the multi-way trigger U4, resetting the input status of the 4-pin, 7-pin, and 8-pin of the multi-way trigger U4 and waiting for CP to input the signal again to cycle.

[0033] In one embodiment, in addition to being provided by the power supply, the preset parameters can be input through voltage division through resistors R13, R14, and R15. The preset parameters can also be fed back to operational amplifiers U9 and U10 for comparison and then fed back to the processor. The processor confirms the adjustment direction of RT based on the output status of OUT1 and OUT2. If RT remains unchanged when both OUT1 and OUT2 are high, and the RT resistance is increased or decreased when either is low. Resistors R13, R14, and R15 can be set to sliding resistors according to the required voltage division ratio, and the wiper is adjusted to change the corresponding voltage division coefficient; when the corresponding connection ends of resistors R1, R2, R3, and R4 require other program control, the processor enables pull-down resistors, and when there is no other program control, resistors are used instead of enabling.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A temperature acquisition circuit for an on-vehicle electronic oil pump, characterized in that: The invention comprises a plurality of digital potentiometers, a plurality of resistors, a multi-channel operational amplifier, a multi-channel trigger, and a NOT gate. The first pins of the digital potentiometers U2 and the digital potentiometer U3 in the plurality of digital potentiometers are connected to the CLK terminal; the second pins of the digital potentiometers U2 and the digital potentiometer U3 are connected to the first and seventh pins of the multi-channel operational amplifier U5 respectively; the eighth pins of the digital potentiometers U2 and the digital potentiometer U3, the twentieth pin of the multi-channel trigger U4, the fourth pin of the multi-channel operational amplifier U5, the fifth pin of the NOT gate U1, the resistor R5, and one end of the resistor R6 are connected to a power supply; the seventh pin of the digital potentiometer U2 is connected to the second and fourth pins of the multi-channel trigger U4; the seventh pin of the digital potentiometer U3 is connected to the fifth and seventh pins of the multi-channel trigger U4; the sixth and eighth pins of the multi-channel trigger U4 are connected to the FB terminal, and the eleventh pin is connected to the CP terminal; the fourth pin of the NOT gate U1 is connected to the multi-channel trigger The first and second pins of U4 are connected to the ninth pin of the multi-channel trigger U4; the other end of the resistor R5 is connected to the third pin of the digital potentiometer U2 and the third and twelfth pins of the multi-channel operational amplifier U5; the other end of the resistor R6 is connected to the third pin of the digital potentiometer U3 and the fifth and tenth pins of the multi-channel operational amplifier U5; the second and sixth pins of the multi-channel operational amplifier U5 are connected to the RT terminal, the thirteenth and ninth pins are connected to one end of the resistor R7 and the resistor R8 respectively, and the fourteenth and eighth pins are connected to the other end of the resistor R7 and the resistor R8 respectively; the third pin of the NOT gate U1, the fourth, fifth and sixth pins of the digital potentiometers U2 and the digital potentiometer U3, and the eleventh pin of the multi-channel operational amplifier U5 are grounded; among them, the NOT gate model is SN74LVC1; the digital potentiometer model is AD5220; the multi-channel operational amplifier model is OPA4131; and the multi-channel trigger model is 74HC273PW118.

2. The temperature acquisition circuit of the vehicle-mounted electronic oil pump according to claim 1, characterized in that: The invention also includes several operational amplifiers and demultiplexers, wherein the third pin of the operational amplifier U7 among the several operational amplifiers is connected to the other end of the resistor R5, the second pin is connected to the other end of the resistor R6, and the first pin is connected to the tenth and eleventh pins of the demultiplexer U6; the third pin of the operational amplifier U8 is connected to one end of the resistor R10 and the resistor R11, the second pin is connected to one end of the resistor R9 and the resistor R12, and the first pin is connected to the other end of the resistor R12; the first and twelfth pins of the demultiplexer U6 are connected to the other end of the resistor R8, the second and thirteenth pins are connected to the other end of the resistor R7, the fourteenth and fifteenth pins are connected to the other end of the resistor R10 and the resistor R9 respectively, and the sixteenth pin is connected to the power supply; the other end of the resistor R11 and the sixth, seventh, and eighth pins of the demultiplexer U6 are grounded; The multiplexer model is 74HC4053; the op amp model is LM358.

3. The temperature acquisition circuit of the vehicle-mounted electronic oil pump according to claim 2, characterized in that: The second pin of the operational amplifier U9 among the several operational amplifiers is connected to the third pin of the operational amplifier U10 and the first pin of the operational amplifier U8, and the first pin is connected to the OUT1 terminal; the first pin of the operational amplifier U10 is connected to the OUT2 terminal; the operational amplifier model is LM358.

4. The temperature acquisition circuit of the vehicle-mounted electronic oil pump according to claim 1, characterized in that: One end of the resistor R1 among the multiple resistors is connected to the seventh pin of the digital potentiometer U2; one end of the resistor R2 is connected to the third pin of the multi-way trigger U4; one end of the resistor R3 is connected to the seventh pin of the digital potentiometer U3; one end of the resistor R4 is connected to the FB terminal; the other ends of the resistors R1, R2, R3 and R4 are grounded.

5. The temperature acquisition circuit of the vehicle-mounted electronic oil pump according to claim 3, characterized in that: One end of the resistor R15 among the resistors is connected to the power supply, and the tap end and the other end are connected to one end of the resistor R13 and the third pin of the operational amplifier U9; the other end of the resistor R13 is connected to one end of the resistor R14 and the second pin of the operational amplifier U10; the other end of the resistor R14 is grounded.

6. The temperature acquisition circuit of the vehicle-mounted electronic oil pump according to claim 5, characterized in that: The resistor R15 is a sliding resistor.

7. The temperature acquisition method of the vehicle-mounted electronic oil pump according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Set up an acquisition circuit and a processor, the acquisition circuit receives the CP signal and samples the RT temperature signal; S2. The acquisition circuit feeds back the OUT1 and OUT2 status signals and the FB signal to the processor based on the CP signal input; S3. The acquisition circuit takes values ​​of the RT signal at the first and second inputs of the CP signal respectively; S4. The acquisition circuit feeds back two RT value signals to the processor when the CP signal is input for the third time. The processor adjusts the RT resistance value based on the positive and negative values ​​and the states of OUT1 and OUT2, and feeds back the fourth CP signal to reset the circuit and then cycle.

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