A hysteretic control circuit based on over-temperature and over-voltage

Abstract

This utility model discloses a hysteresis control circuit based on over-temperature and over-voltage, including over-voltage and over-current protection circuits. The over-voltage protection circuit includes a signal conditioning module, a core amplification module, and a signal processing module. The signal conditioning module consists of voltage divider resistors R1~R6, comparator IC1, and filter capacitors C1 and C2. The core amplification module includes filter capacitor C3. The signal processing module consists of diodes D1 and D2. The over-temperature protection circuit includes a reference voltage and temperature sensing circuit, an operational amplifier signal processing circuit, a power switch drive circuit, and auxiliary circuits. The reference voltage and temperature sensing circuit consists of voltage divider resistors R8, R9, R12, and R13, comparator IC2, and filter capacitors C4 and C7. The operational amplifier signal processing circuit includes filter capacitor C6. The power switch drive circuit includes resistors R10, R11, and R14, filter capacitor C4, and MOSFET Q1. The auxiliary circuit consists of diode D3 and resistor R7. This utility model has strong real-time performance, fast response speed, and high robustness.

Description

Technical Field

[0001] This utility model belongs to the field of switching power supply design, specifically relating to a hysteresis control circuit based on over-temperature and over-voltage. Background Technology

[0002] With the widespread application of electronic devices in automobiles, industrial control, and consumer electronics, their safety and reliability have become core concerns for industry development. Especially in automotive electronic systems, the complex operating environment can easily cause devices to fail due to overtemperature or overvoltage, leading to system malfunctions or even safety accidents. Existing hysteresis control circuits have fixed loop widths, resulting in unstable frequencies, insufficient dynamic response speed, and a lack of adaptive adjustment mechanisms. Utility Model Content

[0003] The purpose of this invention is to provide a hysteresis control circuit based on over-temperature and over-pressure to solve the problems of unstable frequency and insufficient dynamic response in existing hysteresis control circuits.

[0004] To achieve the above objectives, the technical solution adopted by this utility model includes: A hysteresis control circuit based on over-temperature and over-voltage includes an over-voltage protection circuit and an over-current protection circuit. The over-voltage protection circuit includes a signal conditioning module, a core amplification module, and a signal processing module. The signal conditioning module consists of voltage divider resistors R1, R2, R3, R4, R5, and R6, a comparator IC1, and filter capacitors C1 and C2. The core amplification module includes a filter capacitor C3. The signal processing module consists of diodes D1 and D2. One end of the voltage divider resistors R2 and R3 is connected to the input voltage, and the other end is connected to one end of the filter capacitor C1, one end of the voltage divider resistor R1, and pin 4 of the comparator IC1. The other end of the filter capacitor C1 is connected to the voltage divider resistor R1. The other end is grounded; the first reference voltage VCF2 is connected to one end of the voltage divider resistor R4, and its other end is connected to one end of the filter capacitor C2, one end of the voltage divider resistors R5 and R6, and pin 3 of the comparator IC1; the other end of the filter capacitor C2 and the other end of the voltage divider resistor R5 are grounded together; the first reference voltage VCF2 is also connected to pin 5 of the comparator IC1 and one end of the filter capacitor C3, and the other end of the filter capacitor C3 is grounded; the other end of the voltage divider resistor R6 is connected to the anode of the diode D2, and the cathode of the diode D2 is connected to pin 1 of the comparator IC1 and the cathode of the diode D1; pin 2 of the comparator IC1 is grounded, and the anode of the diode D1 is connected to the SS pin of the PWM controller; The over-temperature protection circuit includes a reference voltage and temperature sensing circuit, an operational amplifier signal processing circuit, a power switch drive circuit, and an auxiliary circuit. The reference voltage and temperature sensing circuit consists of voltage divider resistors R8, R9, R12, and R13, comparator IC2, and filter capacitors C4 and C7. The operational amplifier signal processing circuit includes a filter capacitor C6. The power switch drive circuit includes resistors R10, R11, and R14, a filter capacitor C4, and a MOSFET Q1. The auxiliary circuit consists of diode D3 and resistor R7. One end of resistors R9 and R13 is connected to the second reference voltage Vref. The other end of resistor R9 is connected to one end of filter capacitor C4, one end of voltage divider resistor R8, and pin 4 of comparator IC2. The other end of filter capacitor C4 and the other end of voltage divider resistor R8 are grounded. The other end of R13 is connected to one end of the filter capacitor C7, one end of the voltage divider resistor R12, one end of the resistor R7, and pin 3 of comparator IC2; the other end of the filter capacitor C7 and the other end of the voltage divider resistor R12 are grounded together; pin 5 of comparator IC2 and one end of the filter capacitor C6 are connected to one end of resistor R14; pin 2 of comparator IC2 and the other end of the filter capacitor C6 are both grounded; the other end of resistor R7 is connected to the anode of diode D3; the cathode of diode D3 is connected to pin 1 of comparator IC2, the other end of resistor R14, and one end of resistor R10; the other end of resistor R10 is connected to one end of resistor R11, one end of filter capacitor C5, and pin 1 of MOSFET Q1; the other end of resistor R11, the other end of filter capacitor C5, and pin 2 of MOSFET Q1 are grounded together; pin 3 of MOSFET Q1 is connected to the SS pin of the PWM controller.

[0005] Furthermore, comparator IC1 is model RS8411XF, and diodes D1 and D2 are Changjing 1N4148WT; comparator IC2 is model RS8411XF, diode D3 is Changjing 1N4148WT, and MOSFET Q1 is a CJ3400 MOSFET.

[0006] Furthermore, when VCF2 = 5.1V, the values ​​of the resistors and capacitors are as follows: R1: 1K, R2: 15K, R3: 15K, R4: 10K, R5: 10K, R6: 68K, C1: 0.1uF / 50V, VCF2: 0.1uF / 50V, C3: 0.1uF / 50V.

[0007] Furthermore, when VCF=10V, the values ​​of the resistors and capacitors are as follows: R7: 68K, R8: 39K, R9: 2.4K, R10: 10K, R11: 10K, R12: 10K, R14: 1K, C4: 0.1uF / 50V, C5: 0.1uF / 50V, C6: 0.1uF / 50V, C7: 0.1uF / 50V, R13: NTC 10K.

[0008] Compared to existing technologies, this invention defines a method for controlling overvoltage and overtemperature protection and recovery in DC power supply systems by allowing the downstream circuit to switch its output voltage through sampling and setting the upstream voltage. The sampling switching threshold can be changed by adjusting the reference level VCF or the value of the voltage divider resistor. This invention offers advantages such as strong real-time performance, fast response speed (microsecond level), and high robustness, and has been widely applied in power electronics applications such as inverters and frequency converters. It achieves rapid switching of switching states through a hysteresis comparator, effectively suppressing ripple and improving system stability. It provides core safety assurance for key areas such as automotive electronics and smart grids, with broad application prospects. Attached Figure Description

[0009] Figure 1 This is an overvoltage protection circuit. Figure 2 This is an over-temperature protection circuit. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to the accompanying drawings: The present invention provides a hysteresis control circuit based on over-temperature and over-pressure, including an over-pressure protection circuit and an over-temperature protection circuit. like Figure 1 As shown, the overvoltage protection circuit includes a signal conditioning module, a core amplification module, and a signal processing module. The signal conditioning module consists of voltage divider resistors R1, R2, R3, R4, R5, and R6, comparator IC1, and filter capacitors C1 and C2. The core amplification module includes filter capacitor C3. The signal processing module consists of diodes D1 and D2. Specifically, one end of voltage divider resistors R2 and R3 is connected to the input voltage (VIN+), and the other end is connected to one end of filter capacitor C1, one end of voltage divider resistor R1, and pin 4 of comparator IC1. The other end of filter capacitor C1 and the other end of voltage divider resistor R1 are grounded together. The first reference voltage (VCF2) is connected to one end of voltage divider resistor R4, and the other end of it is connected to one end of filter capacitor C2, one end of voltage divider resistors R5 and R6, and pin 3 of comparator IC1. The other end of filter capacitor C2 and the other end of voltage divider resistor R5 are grounded together. The first reference voltage (VCF2) is also connected to pin 5 of comparator IC1 and one end of filter capacitor C3, with the other end of filter capacitor C3 grounded. The other end of voltage divider resistor R6 is connected to the anode of diode D2, and the cathode of diode D2 is connected to pin 1 of comparator IC1 and the cathode of diode D1. Pin 2 of comparator IC1 is grounded, and the anode of diode D1 is connected to the SS pin of the PWM controller.

[0011] In the above-mentioned overvoltage protection circuit, the signal conditioning module sets the reference voltage at the non-inverting input of comparator IC1 by setting the resistance values ​​of R4 and R5, and sets the overvoltage protection threshold at the inverting input of comparator IC1 by setting the resistance values ​​of R2, R3, and R1. When the inverting input voltage does not reach the overvoltage protection threshold, the non-inverting input voltage when overvoltage protection is not triggered is (R5 / (R4+R5))VCF2, comparator IC1 outputs a high level, and diode D1 is cut off. When the inverting input voltage reaches the protection threshold, the voltage at the negative terminal (pin 4) of comparator IC1 is higher than the voltage at the positive terminal (pin 3), and the inverting input voltage is greater than the non-inverting input voltage when overvoltage protection is not triggered. Comparator IC1 outputs a low level, diode D1 conducts, and pulls the SS pin low, thus achieving the overvoltage protection function. At this time, when the voltage at the non-inverting input terminal triggers overvoltage protection, the input voltage at the non-inverting terminal is ((R5 / / R6) / (R4+R5 / / R6))VCF2, which is obviously lower than the input voltage at the non-inverting terminal when overvoltage protection is not triggered. If it is necessary to disable the overvoltage function, the input voltage at the inverting terminal needs to provide a voltage lower than the trigger protection threshold. The input voltage at the inverting terminal is (R1 / (R1+(R2 / / R3)))*VIN+, and VIN+ must be lower than the protection point.

[0012] When the input voltage at the inverting input of comparator IC1 reaches the set threshold voltage, the core amplification module outputs a corresponding low level at its output terminal (pin 1) to change the operating state of the subsequent circuit.

[0013] Pin 5 of comparator IC1 is connected to VCF2 and is protected against interference through filter capacitor C3. Pin 2 of comparator IC1 is connected to GND. In the signal processing module, diode D1 is used for unidirectional conduction, converting the op-amp output signal into a unidirectional signal output from the SS terminal; diode D2 and voltage divider resistor R6 require the input voltage at the inverting terminal to be lower than the trigger protection threshold, and VIN+ must be lower than the protection point.

[0014] In this example, the comparator IC1 is model RS8411XF, and diodes D1 and D2 are Changjing 1N4148WT. When VCF2 = 5.1V, the values ​​of the resistors and capacitors are as follows: R1: 1K, R2: 15K, R3: 15K, R4: 10K, R5: 10K, R6: 68K, C1: 0.1uF / 50V, VCF2: 0.1uF / 50V, C3: 0.1uF / 50V.

[0015] like Figure 2As shown, the over-temperature protection circuit includes a reference voltage and temperature sensing circuit, an operational amplifier signal processing circuit, a power switch drive circuit, and an auxiliary circuit. The reference voltage and temperature sensing circuit consists of voltage divider resistors R8, R9, R12, and R13, comparator IC2, and filter capacitors C4 and C7. The operational amplifier signal processing circuit includes a filter capacitor C6. The power switch drive circuit includes resistors R10, R11, and R14, a filter capacitor C4, and a MOSFET Q1. The auxiliary circuit consists of diode D3 and resistor R7. Specifically, one end of resistors R9 and R13 is connected to the second reference voltage Vref; the other end of resistor R9 is connected to one end of filter capacitor C4, one end of voltage divider resistor R8, and pin 4 of comparator IC2; the other end of filter capacitor C4 and the other end of voltage divider resistor R8 are grounded together. The other end of resistor R13 is connected to one end of filter capacitor C7, one end of voltage divider resistor R12, one end of resistor R7, and pin 3 of comparator IC2; the other end of filter capacitor C7 and the other end of voltage divider resistor R12 are grounded together. Pin 5 of comparator IC2 and one end of filter capacitor C6 are connected to one end of resistor R14 (VCF); pin 2 of comparator IC2 and the other end of filter capacitor C6 are both grounded. The other end of resistor R7 is connected to the anode of diode D3; the cathode of diode D3 is connected to pin 1 of comparator IC2, the other end of resistor R14, and one end of resistor R10; the other end of resistor R10 is connected to one end of resistor R11, one end of filter capacitor C5, and pin 1 of MOSFET Q1; the other end of resistor R11, the other end of filter capacitor C5, and pin 2 of MOSFET Q1 are grounded together; pin 3 of MOSFET Q1 is connected to the SS pin of the PWM controller.

[0016] In the above-mentioned over-temperature protection circuit, the reference voltage and temperature sensing circuit sets the reference voltage of the inverting input V- of comparator IC2 by setting the resistance values ​​of R8 and R9, and sets the threshold protection voltage of the non-inverting input of comparator IC2 by setting resistors R7, R12, and R13. When the temperature is 25℃, the inverting input voltage should be higher than the non-inverting input voltage. At this time, comparator IC2 outputs a low level, diode D3 is turned on, and MOSFET Q1 is turned off. When overvoltage protection is not triggered, the non-inverting input voltage is (R12 / / R7) / ((R12 / / R7)+R13))*Vref. As the system temperature rises, the resistance of R13 decreases until the non-inverting input voltage is greater than the inverting input voltage when overvoltage protection is not triggered, triggering the over-temperature protection threshold. Comparator IC2 outputs a high level. At this time, the non-inverting input voltage is only divided by R12. When overvoltage protection is triggered, the non-inverting input voltage is R12 / (R13+R12). If the over-temperature protection function needs to be turned off, the resistance of R7 needs to be higher than the resistance that triggers the over-temperature protection. That is, the temperature needs to recover to a certain threshold to ensure that the non-inverting input voltage is less than the inverting input voltage.

[0017] When the input voltage at the non-inverting input of comparator IC2 reaches a set threshold voltage, the operational amplifier signal processing circuit outputs a corresponding high level to change the operating state of the subsequent circuit.

[0018] In the operational amplifier signal processing circuit, pin 5 of comparator IC2 is connected to VCF and is protected against interference by filter capacitor C5, while pin 2 of comparator IC2 is connected to GND.

[0019] The power switch drive circuit controls the conduction and cutoff of MOSFET Q1 by the high and low levels output from the front-end circuit, thereby controlling the SS pin to stop the PWM controller from working. MOSFET Q1 is responsible for the conduction and cutoff of the controller's SS pin, and filter capacitor C4 is responsible for noise suppression of the output circuit.

[0020] The auxiliary circuit is used for freewheeling or clamping protection to prevent reverse current from damaging components.

[0021] In this example, comparator IC2 is model RS8411XF, diode D3 is Changjing 1N4148WT, MOSFET Q1 is CJ3400 MOSFET, and the values ​​of resistors and capacitors when VCF=10V are as follows: R7: 68K, R8: 39K, R9: 2.4K, R10: 10K, R11: 10K, R12: 10K, R14: 1K, C4: 0.1uF / 50V, C5: 0.1uF / 50V, C6: 0.1uF / 50V, C7: 0.1uF / 50V, R13: NTC 10K.

[0022] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be conceived by those skilled in the art within the technical scope disclosed in the present utility model without creative effort should be included within the protection scope of the present utility model.

Claims

1. A hysteresis control circuit based on over-temperature and over-voltage, comprising an over-voltage protection circuit and an over-current protection circuit, characterized in that: The overvoltage protection circuit includes a signal conditioning module, a core amplification module, and a signal processing module. The signal conditioning module consists of voltage divider resistors R1, R2, R3, R4, R5, and R6, comparator IC1, and filter capacitors C1 and C2. The core amplification module includes a filter capacitor C3. The signal processing module consists of diodes D1 and D2. One end of voltage divider resistors R2 and R3 is connected to the input voltage, and the other end is connected to one end of filter capacitor C1, one end of voltage divider resistor R1, and pin 4 of comparator IC1. The other end of filter capacitor C1 and the other end of voltage divider resistor R1 are grounded. The first reference voltage VC... F2 is connected to one end of the voltage divider resistor R4, and its other end is connected to one end of the filter capacitor C2, one end of the voltage divider resistors R5 and R6, and pin 3 of the comparator IC1; the other end of the filter capacitor C2 and the other end of the voltage divider resistor R5 are grounded together; the first reference voltage VCF2 is also connected to pin 5 of the comparator IC1 and one end of the filter capacitor C3, and the other end of the filter capacitor C3 is grounded; the other end of the voltage divider resistor R6 is connected to the anode of diode D2, and the cathode of diode D2 is connected to pin 1 of the comparator IC1 and the cathode of diode D1; pin 2 of the comparator IC1 is grounded, and the anode of diode D1 is connected to the SS pin of the PWM controller; The over-temperature protection circuit includes a reference voltage and temperature sensing circuit, an operational amplifier signal processing circuit, a power switch drive circuit, and an auxiliary circuit. The reference voltage and temperature sensing circuit consists of voltage divider resistors R8, R9, R12, and R13, comparator IC2, and filter capacitors C4 and C7. The operational amplifier signal processing circuit includes a filter capacitor C6. The power switch drive circuit includes resistors R10, R11, and R14, a filter capacitor C4, and a MOSFET Q1. The auxiliary circuit consists of diode D3 and resistor R7. One end of resistors R9 and R13 is connected to the second reference voltage Vref. The other end of resistor R9 is connected to one end of filter capacitor C4, one end of voltage divider resistor R8, and pin 4 of comparator IC2. The other end of filter capacitor C4 and the other end of voltage divider resistor R8 are grounded.

13. The other end is connected to one end of the filter capacitor C7, one end of the voltage divider resistor R12, one end of the resistor R7, and pin 3 of the comparator IC2; the other end of the filter capacitor C7 and the other end of the voltage divider resistor R12 are grounded together; pin 5 of the comparator IC2 and one end of the filter capacitor C6 are connected to one end of the resistor R14; pin 2 of the comparator IC2 and the other end of the filter capacitor C6 are both grounded; the other end of the resistor R7 is connected to the anode of the diode D3; the cathode of the diode D3 is connected to pin 1 of the comparator IC2, the other end of the resistor R14, and one end of the resistor R10; the other end of the resistor R10 is connected to one end of the resistor R11, one end of the filter capacitor C5, and pin 1 of the MOSFET Q1; the other end of the resistor R11, the other end of the filter capacitor C5, and pin 2 of the MOSFET Q1 are grounded together; pin 3 of the MOSFET Q1 is connected to the SS pin of the PWM controller.

2. The hysteretic control circuit based on over-temperature and over-voltage as claimed in claim 1, wherein: The comparator IC1 is model RS8411XF, and diodes D1 and D2 are Changjing 1N4148WT; the comparator IC2 is model RS8411XF, diode D3 is Changjing 1N4148WT, and MOSFET Q1 is a CJ3400 MOSFET.

3. The hysteretic control circuit based on over-temperature and over-voltage as claimed in claim 1, wherein: When VCF2 = 5.1V, the values ​​of the resistors and capacitors are as follows: R1: 1K, R2: 15K, R3: 15K, R4: 10K, R5: 10K, R6: 68K, C1: 0.1uF / 50V, VCF2: 0.1uF / 50V, C3: 0.1uF / 50V.

4. The hysteretic control circuit based on over-temperature and over-voltage as claimed in claim 1, wherein: When VCF=10V, the values ​​of the resistors and capacitors are as follows: R7: 68K, R8: 39K, R9: 2.4K, R10: 10K, R11: 10K, R12: 10K, R14: 1K, C4: 0.1uF / 50V, C5: 0.1uF / 50V, C6: 0.1uF / 50V, C7: 0.1uF / 50V, R13: NTC 10K.

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