A current-to-frequency conversion circuit with automatic compensation

Abstract

The application discloses a current frequency conversion circuit with automatic compensation function, comprising: an integral circuit, a positive threshold voltage detection circuit, a negative threshold voltage detection circuit, a feedback control circuit, a positive constant current source circuit, a negative constant current source circuit, an analog switch, a temperature acquisition circuit, a compensation control circuit and a pulse output driving circuit.The input of the circuit is a current signal, and the output is a pulse signal, and the input current and the frequency of the output pulse signal are in linear relationship.The circuit realizes the acquisition and conversion of positive and negative input currents through a single channel conversion circuit, can acquire the ambient temperature, automatically compensates the scale coefficient of the conversion circuit according to the temperature, can automatically switch the range according to the size of the current input and carry out feedback control compensation, so that the linearity index in the full temperature range of-30 DEG C to 60 DEG C is better than 50ppm, and the measurement range can reach 60mA, and the application has high application value in the field of control systems with high navigation precision.

Description

Technical Field

[0001] This invention relates to navigation and attitude control technology, and in particular to a current-frequency conversion circuit with automatic compensation function. Background Technology

[0002] The current-frequency conversion circuit is mainly used to collect the current output by acceleration. Its function is to convert the current into a pulse frequency signal proportionally. It is mainly used in the field of navigation, involving the navigation and attitude control of weapons, launch vehicles and satellites.

[0003] The main indicators for evaluating the quality of current-frequency conversion circuits include: measurement range, scaling factor, scaling factor nonlinearity, scaling factor temperature coefficient, and zero-bias stability. The scaling factor is defined as the ratio of the number of output pulses per unit time to the input current, also known as the scaling coefficient K. This coefficient should remain stable under different input conditions and throughout the entire temperature range. This leads to two related indicators: scaling factor nonlinearity and scaling factor temperature coefficient.

[0004] Within a given measurement range, a larger scaling factor results in higher current resolution. The measurement range is limited by the feedback control time and the size of the constant current source. With a fixed constant current source, a longer feedback control time results in a larger measurement range, but a smaller scaling factor, which is detrimental to improving resolution. Traditional current-to-frequency conversion circuits typically have a range within ±20mA, making it difficult to meet large range requirements. Furthermore, their scaling factor has a large temperature coefficient, leading to significant nonlinearity between the output pulse and the input current when operating at full temperature. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a current frequency conversion circuit with automatic compensation function, which realizes the acquisition and conversion of positive and negative input current with a single-channel conversion circuit.

[0006] The technical solution of this invention is:

[0007] A current-frequency conversion circuit with automatic compensation function includes: an integrating circuit U1, a positive threshold voltage detection circuit U2, a negative threshold voltage detection circuit U3, a compensation control circuit U4, a feedback control circuit U5, a positive constant current source circuit U6, a negative constant current source circuit U7, an analog switch U8, and a pulse output drive circuit U10.

[0008] Integrating circuit U1 receives the input current I from the external input. in And the balancing current fed back by analog switch U8, and the integrator circuit U1 for the input current I in The difference between the current and the balance current is integrated, and the integrated voltage is output to the positive threshold voltage detection circuit U2, the negative threshold voltage detection circuit U3 and the compensation control circuit U4 respectively.

[0009] The input current I is detected by the positive threshold voltage detection circuit U2 and the negative threshold voltage detection circuit U3. in The polarity of the input current I is determined. in When the polarity of the input current is positive, analog switch U8 disconnects the positive constant current source circuit U6 and connects the negative constant current source circuit U7, feeding the negative constant current output of the negative constant current source circuit U7 back to the integrator circuit U1 as the balancing current; when the input current I... in When the polarity of the input current is negative, the analog switch U8 connects the positive constant current source circuit U6 and disconnects the negative constant current source circuit U7, and feeds the positive constant current output by the positive constant current source circuit U6 back to the integrator circuit U1 as the balancing current.

[0010] The compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage, thereby adjusting the control time of the analog switch U8 to feed back the balance current to the integrator circuit U1.

[0011] The feedback control circuit U5 generates a pulse signal and outputs it to the outside through the pulse output drive circuit U10.

[0012] Preferably, in the input current I in When the input current is positive, the integrated voltage output by the integrating circuit U1 decreases;

[0013] When the integral voltage is lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the integral circuit U1, the positive threshold voltage detection circuit U2, the feedback control circuit U5, the analog switch U8 and the negative constant current source U7 form a feedback drive loop. The analog switch U8 introduces the negative constant current output by the negative constant current source U7 into the integral circuit U1, thereby forming a closed loop circuit under positive input current. The feedback control circuit U5 outputs a pulse signal to the outside through the pulse output drive circuit U10 according to the control cycle of the closed loop circuit.

[0014] Conversely, when the integrated voltage is not lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7.

[0015] Preferably, when the positive input current is greater than the absolute value of the negative constant current output by the negative constant current source circuit U7, the closed-loop circuit is in a saturated state.

[0016] When the positive input current is less than the absolute value of the negative constant current output by the negative constant current source circuit U7, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage.

[0017] Preferably, when the positive input current is greater than the upper limit value I of the positive input current inside the feedback control circuit U5... ref1When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7:

[0018] The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrator circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 does not transmit a compensation signal to the feedback control circuit U5, keeping the control period of the closed-loop circuit unchanged.

[0019] Preferably, when the positive input current is less than the upper limit value I of the positive input current inside the feedback control circuit U5 ref1 When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7:

[0020] The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrator circuit U1 is greater than the set value. If the signal period is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrator circuit U1 to compensate the control period and thus compensate the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 does not feed back a compensation signal to the feedback control circuit U5, keeping the control period unchanged.

[0021] Preferably, in the input current I in When the input current is negative, the output integral voltage increases;

[0022] When the integrated voltage is higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the integrating circuit U1, the negative threshold voltage detection circuit U3, the feedback control circuit U5, the analog switch U8, and the positive constant current source U6 form a feedback drive loop. The analog switch U8 introduces the positive constant current output from the positive constant current U6 into the integrating circuit U1, thus forming a closed-loop circuit under negative input current. The control period of the closed-loop circuit is related to the input current I. in The magnitude is inversely proportional, and the feedback control circuit U5 outputs pulse signals to the outside through the pulse output drive circuit U10 according to the control cycle;

[0023] Conversely, when the integrated voltage is not higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7; the positive reference voltage is less than the negative reference voltage.

[0024] Preferably, when the negative input current is greater than the absolute value of the positive constant current output by the positive constant current source circuit U6, the closed-loop circuit is in a saturated state.

[0025] When the negative input current is less than the absolute value of the positive constant current output by the positive constant current source circuit U6, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage.

[0026] Preferably, when the negative input current is greater than the upper limit value I of the negative input current inside the feedback control circuit U5... ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6:

[0027] The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrator circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 does not transmit a compensation signal to the feedback control circuit U5, keeping the control period of the closed-loop circuit unchanged.

[0028] Preferably, when the negative input current is less than the upper limit value I of the negative input current inside the feedback control circuit U5... ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6:

[0029] The compensation control circuit U4 checks whether the signal period of the integrated voltage output by the integrator circuit U1 is greater than the set value. If the signal period is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 does not feed back a compensation signal to the feedback control circuit U5, keeping the control period unchanged.

[0030] Preferably, it further includes: a temperature acquisition circuit U9;

[0031] Temperature acquisition circuit U9 acquires the ambient temperature and outputs the temperature voltage to compensation control circuit U4;

[0032] The compensation control circuit U4 receives the temperature voltage, processes it digitally, and outputs it to the feedback control circuit U5. The feedback control circuit U5 uses the temperature voltage for judgment and compensates the control cycle when the ambient temperature exceeds the range.

[0033] The circuit used in this invention has the following advantages and beneficial effects compared with the prior art:

[0034] 1. The circuit provided by this invention can collect ambient temperature and automatically compensate the scaling coefficient of the conversion circuit for temperature. It can also automatically switch the range and perform feedback control compensation according to the magnitude of the current input current.

[0035] 2. The linearity index of this invention is better than 50ppm in the full temperature range of -30℃ to 60℃ and the measurement range can reach 60mA. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a current-frequency conversion circuit with automatic compensation function according to the present invention.

[0037] In the diagram, U1 is an integrating circuit; U2 is a positive threshold voltage detection circuit; U3 is a negative threshold voltage detection circuit; U4 is a compensation control circuit; U5 is a feedback control circuit; U6 is a positive constant current source circuit; U7 is a negative constant current source circuit; U8 is an analog switch; U9 is a temperature acquisition circuit; and U10 is a pulse output drive circuit. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] like Figure 1 As shown, the present invention provides a current frequency conversion circuit with automatic compensation function, comprising: an integrating circuit U1, a positive threshold voltage detection circuit U2, a negative threshold voltage detection circuit U3, a compensation control circuit U4, a feedback control circuit U5, a positive constant current source circuit U6, a negative constant current source circuit U7, an analog switch U8, and a pulse output drive circuit U10.

[0040] Integrating circuit U1 receives the input current I from the external input. in And the balancing current fed back by analog switch U8, and the integrator circuit U1 for the input current I in The difference between the current and the balance current is integrated, and the integrated voltage is output to the positive threshold voltage detection circuit U2, the negative threshold voltage detection circuit U3 and the compensation control circuit U4 respectively.

[0041] The positive threshold voltage detection circuit U2 and the negative threshold voltage detection circuit U3 output square wave voltages to the feedback control circuit U5. The feedback control circuit U5 then adjusts the voltage based on the input current I. in The polarity controls the on / off state of the analog switch U8, thereby feeding back the balanced current output by the positive constant current source circuit U6 or the negative constant current source circuit U7 to the integrator circuit U1.

[0042] The input current I is detected by the positive threshold voltage detection circuit U2 and the negative threshold voltage detection circuit U3. in The polarity of the input current I is determined. in When the polarity of the input current is positive, analog switch U8 disconnects the positive constant current source circuit U6 and connects the negative constant current source circuit U7, feeding the negative constant current output of the negative constant current source circuit U7 back to the integrator circuit U1 as the balancing current; when the input current I... inWhen the polarity of the input current is negative, the analog switch U8 connects the positive constant current source circuit U6 and disconnects the negative constant current source circuit U7, and feeds the positive constant current output by the positive constant current source circuit U6 back to the integrator circuit U1 as the balancing current.

[0043] The compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage, thereby adjusting the control time of the analog switch U8 to feed back the balance current to the integrator circuit U1.

[0044] The feedback control circuit U5 generates pulse signals according to the control cycle and outputs them to the outside through the pulse output drive circuit U10.

[0045] a) When the input current I in When it is a positive input current, i.e., the input current I in The charge flows into the integrator circuit U1 in the positive direction. The integrator circuit U1 integrates the charge, and the output integrated voltage decreases.

[0046] When the integrated voltage is lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the integrator circuit U1, the positive threshold voltage detection circuit U2, the feedback control circuit U5, the analog switch U8, and the negative constant current source U7 form a feedback drive loop. The analog switch U8 introduces the negative constant current output from the negative constant current source U7 into the integrator circuit U1, thus forming a closed-loop circuit under positive input current. The control period of the closed-loop circuit is related to the input current I. in The magnitude is inversely proportional; the feedback control circuit U5 outputs pulse signals to the outside through the pulse output drive circuit U10 according to the control cycle; the input current I... in The magnitude of the pulse is proportional to the frequency of the pulse output by the pulse output drive circuit U10.

[0047] Conversely, when the integrated voltage is not lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7.

[0048] a1) When the positive input current is greater than the absolute value of the negative constant current output by the negative constant current source circuit U7, the closed-loop circuit is in a saturated state.

[0049] a2) When the positive input current is greater than the upper limit value I of the positive input current inside the feedback control circuit U5 ref1 When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7:

[0050] The compensation control circuit U4 automatically determines whether the signal period of the integrated voltage output by the integrator circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby automatically adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 does not transmit a compensation signal to the feedback control circuit U5, keeping the control period of the closed-loop circuit unchanged.

[0051] a3) When the positive input current is less than the upper limit value I of the positive input current inside the feedback control circuit U5 ref1 When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7:

[0052] The compensation control circuit U4 automatically determines whether the signal period of the integrated voltage output by the integrator circuit U1 is greater than the set value. If the signal period is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby automatically adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 does not feed back a compensation signal to the feedback control circuit U5, and keeps the control period unchanged.

[0053] b) When the input current I in When the input current is negative, i.e., the input current I in The charge flows into the integrator U1 in the opposite direction, and the integrator U1 performs charge integration, causing the output integrated voltage to rise.

[0054] When the integrated voltage is higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the integrating circuit U1, the negative threshold voltage detection circuit U3, the feedback control circuit U5, the analog switch U8, and the positive constant current source U6 form a feedback drive loop. The analog switch U8 introduces the positive constant current output from the positive constant current U6 into the integrating circuit U1, thus forming a closed-loop circuit under negative input current. The control period of the closed-loop circuit is related to the input current I. in The magnitude is inversely proportional, and the feedback control circuit U5 outputs pulse signals to the outside through the pulse output drive circuit U10 according to the control cycle;

[0055] Conversely, when the integrated voltage is not higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7. The positive reference voltage is less than the negative reference voltage.

[0056] b1) When the negative input current is greater than the absolute value of the positive constant current output by the positive constant current source circuit U6, the closed-loop circuit is in a saturated state.

[0057] b2) When the negative input current is greater than the upper limit value I of the negative input current inside the feedback control circuit U5 ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6:

[0058] The compensation control circuit U4 automatically determines whether the signal period of the integrated voltage output by the integrator circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby automatically adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrator circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 does not transmit a compensation signal to the feedback control circuit U5, keeping the control period of the closed-loop circuit unchanged.

[0059] b3) When the negative input current is less than the upper limit value I of the negative input current inside the feedback control circuit U5 ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6:

[0060] The compensation control circuit U4 checks whether the signal period of the integrated voltage output by the automatic integrating circuit U1 is greater than the set value. If the signal period is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby automatically adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrating circuit U1 to compensate for the control period and thus compensate for the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 does not feed back a compensation signal to the feedback control circuit U5, keeping the control period unchanged.

[0061] Furthermore, the present invention provides a current-frequency conversion circuit with automatic compensation function, which further includes a temperature acquisition circuit U9. The temperature acquisition circuit U9 acquires the ambient temperature and outputs a temperature voltage to the compensation control circuit U4; the compensation control circuit U4 receives the temperature voltage, performs digital processing, and outputs it to the feedback control circuit U5; the feedback control circuit U5 uses the temperature voltage for judgment and performs temperature compensation processing on the control cycle when the ambient temperature exceeds the range. When the closed-loop circuit is working, the temperature acquisition circuit U9 acquires the ambient temperature in real time and transmits the digital ambient temperature information to the feedback control circuit U5 in real time through the compensation control circuit U4. The feedback control circuit U5 judges the ambient temperature based on the temperature compensation value stored in the circuit and performs temperature compensation on the control cycle when the ambient temperature exceeds the range, thereby improving the temperature performance of the current-frequency conversion circuit and reducing the scaling factor temperature coefficient.

[0062] According to the above implementation, the linearity of the current-frequency conversion circuit can be better than 50ppm over the entire temperature range and the measurement range can reach 60mA.

[0063] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. Where there is no conflict, the embodiments of this application and the technical features thereof can be combined with each other.

[0064] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A current-frequency conversion circuit with automatic compensation function, characterized in that, include: Integrating circuit U1, positive threshold voltage detection circuit U2, negative threshold voltage detection circuit U3, compensation control circuit U4, feedback control circuit U5, positive constant current source circuit U6, negative constant current source circuit U7, analog switch U8, and pulse output drive circuit U10; Integrating circuit U1 receives the input current I from the external input. in And the balancing current fed back by analog switch U8, and the integrator circuit U1 for the input current I in The difference between the current and the balance current is integrated, and the integrated voltage is output to the positive threshold voltage detection circuit U2, the negative threshold voltage detection circuit U3 and the compensation control circuit U4 respectively. The input current I is detected by the positive threshold voltage detection circuit U2 and the negative threshold voltage detection circuit U3. in The polarity of the input current I is determined. in When the polarity of the input current is positive, analog switch U8 disconnects the positive constant current source circuit U6 and connects the negative constant current source circuit U7, feeding the negative constant current output of the negative constant current source circuit U7 back to the integrator circuit U1 as the balancing current; when the input current I... in When the polarity of the input current is negative, the analog switch U8 connects the positive constant current source circuit U6 and disconnects the negative constant current source circuit U7, and feeds the positive constant current output by the positive constant current source circuit U6 back to the integrator circuit U1 as the balancing current. The compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage, thereby adjusting the control time of the analog switch U8 to feed back the balance current to the integrator circuit U1. The feedback control circuit U5 generates a pulse signal and outputs it to the outside through the pulse output drive circuit U10.

2. The current-frequency conversion circuit with automatic compensation function according to claim 1, characterized in that, In the input current I in When the input current is positive, the integrated voltage output by the integrating circuit U1 decreases; When the integral voltage is lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the integral circuit U1, the positive threshold voltage detection circuit U2, the feedback control circuit U5, the analog switch U8 and the negative constant current source U7 form a feedback drive loop. The analog switch U8 introduces the negative constant current output by the negative constant current source U7 into the integral circuit U1, thereby forming a closed loop circuit under positive input current. The feedback control circuit U5 outputs a pulse signal to the outside through the pulse output drive circuit U10 according to the control cycle of the closed loop circuit. Conversely, when the integrated voltage is not lower than the positive reference voltage of the positive threshold voltage detection circuit U2, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7.

3. A current-frequency conversion circuit with automatic compensation function according to claim 2, characterized in that, When the positive input current is greater than the absolute value of the negative constant current output by the negative constant current source circuit U7, the closed-loop circuit is in a saturated state. When the positive input current is less than the absolute value of the negative constant current output by the negative constant current source circuit U7, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage.

4. A current-frequency conversion circuit with automatic compensation function according to claim 3, characterized in that, When the positive input current is greater than the upper limit value I of the positive input current inside the feedback control circuit U5 ref1 When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7: The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrating circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrating circuit U1 to compensate for the control period, thereby compensating for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 will not transmit the compensation signal to the feedback control circuit U5, thus keeping the control period of the closed-loop circuit unchanged.

5. A current-frequency conversion circuit with automatic compensation function according to claim 4, characterized in that, When the positive input current is less than the upper limit value I of the positive input current inside the feedback control circuit U5 ref1 When the value is less than the absolute value of the negative constant current output by the negative constant current source circuit U7: The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrator circuit U1 is greater than the set value. If the signal period is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the negative constant current to the integrator circuit U1 to compensate for the control period, thereby compensating for the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 will not feed back the compensation signal to the feedback control circuit U5, and the control period will remain unchanged.

6. A current-frequency conversion circuit with automatic compensation function according to claim 5, characterized in that, In the input current I in When the input current is negative, the output integral voltage increases; When the integrated voltage is higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the integrating circuit U1, the negative threshold voltage detection circuit U3, the feedback control circuit U5, the analog switch U8, and the positive constant current source U6 form a feedback drive loop. The analog switch U8 introduces the positive constant current output from the positive constant current U6 into the integrating circuit U1, thus forming a closed-loop circuit under negative input current. The control period of the closed-loop circuit is related to the input current I. in The magnitude is inversely proportional, and the feedback control circuit U5 outputs pulse signals to the outside through the pulse output drive circuit U10 according to the control cycle; Conversely, when the integrated voltage is not higher than the negative reference voltage of the negative threshold voltage detection circuit U3, the analog switch U8 disconnects the positive constant current source circuit U6 and the negative constant current source circuit U7; the positive reference voltage is less than the negative reference voltage.

7. A current-frequency conversion circuit with automatic compensation function according to claim 6, characterized in that, When the negative input current is greater than the absolute value of the positive constant current output by the positive constant current source circuit U6, the closed-loop circuit is in a saturated state. When the negative input current is less than the absolute value of the positive constant current output by the positive constant current source circuit U6, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5 according to the signal period of the integral voltage.

8. A current-frequency conversion circuit with automatic compensation function according to claim 7, characterized in that, When the negative input current exceeds the upper limit I of the negative input current inside the feedback control circuit U5 ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6: The compensation control circuit U4 determines whether the signal period of the integrated voltage output by the integrator circuit U1 is less than the set value. If the signal period is less than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrator circuit U1 to compensate for the control period, thereby compensating for the output pulse frequency. If the signal period is greater than the set value, the compensation control circuit U4 will not transmit the compensation signal to the feedback control circuit U5, thus keeping the control period of the closed-loop circuit unchanged.

9. A current-frequency conversion circuit with automatic compensation function according to claim 8, characterized in that, When the negative input current is less than the upper limit value I of the negative input current inside the feedback control circuit U5 ref2 When the value is less than the absolute value of the positive constant current output by the positive constant current source circuit U6: If the signal period of the integrated voltage output by the compensation control circuit U4 and the integrator circuit U1 is greater than the set value, the compensation control circuit U4 transmits a compensation signal to the feedback control circuit U5, thereby adjusting the control time of the analog switch U8 feeding back the positive constant current to the integrator circuit U1 to compensate for the control period, thereby compensating for the output pulse frequency. If the signal period is less than the set value, the compensation control circuit U4 will not feed back the compensation signal to the feedback control circuit U5, and the control period will remain unchanged.

10. A current-frequency conversion circuit with automatic compensation function according to any one of claims 1 to 9, characterized in that, Also includes: Temperature acquisition circuit U9; Temperature acquisition circuit U9 acquires the ambient temperature and outputs the temperature voltage to compensation control circuit U4; The compensation control circuit U4 receives the temperature voltage, processes it digitally, and outputs it to the feedback control circuit U5. The feedback control circuit U5 uses the temperature voltage for judgment and compensates the control cycle when the ambient temperature exceeds the range.

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