Over / under voltage protection circuit and PIM module

Abstract

The utility model relates to circuit protection technical field discloses a kind of overvoltage and undervoltage protection circuit and PIM module, and the overvoltage and undervoltage protection circuit includes input circuit, output circuit and optocoupler;The input end of input circuit and the output end of rectifier circuit in PIM module are connected, and input voltage is received by the output end of rectifier circuit, and the output end of input circuit is connected with optocoupler, and input circuit is used to adjust the opening angle of photosensitive triode of the output side of optocoupler according to input voltage;The input end of output circuit and optocoupler and output end are connected, and output circuit is used to generate overvoltage and undervoltage monitoring waveform signal according to the opening angle of photosensitive triode of the output side of optocoupler, and overvoltage and undervoltage monitoring waveform signal is output to control terminal, the utility model has realized the real-time monitoring of input voltage overvoltage and undervoltage state, and can effectively prevent damage to PIM module and related circuit due to input voltage anomaly.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, specifically to an over / under voltage protection circuit and a PIM module. Background Technology

[0002] Currently, commonly used power integrated modules (PIMs) on the market mainly consist of four parts: a rectifier circuit, an inverter circuit, an over-temperature protection circuit, and a braking circuit. Their corresponding block diagrams are shown below. Figure 1 As shown.

[0003] The PIM module is an integrated circuit (IC) that integrates a rectifier circuit, an inverter circuit, and an NTC temperature sampling circuit. The rectifier circuit converts three-phase AC power into DC power, and the inverter circuit converts DC power back into AC power to drive loads such as motors and compressors. The NTC temperature sampling circuit samples the internal module temperature to prevent damage caused by overheating.

[0004] The existing PIM module has a simple internal structure, which facilitates fault diagnosis. However, it has a major problem: when this module is used in an actual circuit and the input voltage is over-voltage or under-voltage, it can easily damage the motor and the PIM module. Therefore, there is an urgent need for an over-voltage and under-voltage protection circuit suitable for PIM modules and a PIM module with such protection. Utility Model Content

[0005] In view of this, the present invention provides an over / under voltage protection circuit and a PIM module to solve the technical problem of the lack of over / under voltage monitoring in the PIM module.

[0006] Firstly, this utility model provides an over / under voltage protection circuit for use in a PIM module, comprising an input circuit, an output circuit, and an optocoupler;

[0007] The input terminal of the input circuit is connected to the output terminal of the rectifier circuit in the PIM module. The input voltage is received through the output terminal of the rectifier circuit. The output terminal of the input circuit is connected to the optocoupler. The input circuit is used to adjust the turn-on angle of the phototransistor on the output side of the optocoupler according to the input voltage.

[0008] The input terminal of the output circuit is connected to the optocoupler and the output terminal. The output circuit is used to generate over- and under-voltage monitoring waveform signals according to the turn-on angle of the phototransistor on the output side of the optocoupler, and output the over- and under-voltage monitoring waveform signals to the control terminal.

[0009] In some optional implementations, the output circuit includes a charging / discharging circuit and a comparator circuit, wherein the input terminal of the charging / discharging circuit is connected to the output terminal of the optocoupler, the output terminal of the charging / discharging circuit is connected to the input terminal of the comparator circuit, and the output terminal of the comparator circuit is connected to the control terminal.

[0010] The charging and discharging circuit is used to output a comparison voltage signal based on the turn-on angle of the phototransistor on the output side of the optocoupler. The duration for which the comparison voltage signal is less than a preset voltage value is positively correlated with the magnitude of the turn-on angle of the phototransistor on the output side of the optocoupler.

[0011] The comparator circuit is used to output over / under voltage monitoring waveform signals based on the comparison voltage signal.

[0012] In some optional embodiments, the charging and discharging circuit includes a first capacitor, a second capacitor, a third resistor, and a fifth resistor. The first end of the third resistor is connected to the first output terminal of the optocoupler, the first end of the first capacitor, and the first end of the fifth resistor, respectively. The second end of the third resistor is connected to a preset power supply. The second end of the first capacitor is connected to the second output terminal of the optocoupler and the first end of the second capacitor, respectively, and grounded. The second end of the fifth resistor is connected to the second end of the second capacitor and the input terminal of the comparator circuit, respectively.

[0013] In some optional embodiments, the comparator circuit includes a comparator, a first resistor, a second resistor, a sixth resistor, an eighth resistor, and a third capacitor. The non-inverting input of the comparator is connected to the first terminal of the first resistor, the first terminal of the eighth resistor, the first terminal of the third capacitor, and the first terminal of the sixth resistor, respectively. The second terminal of the first resistor is connected to a preset power supply. The second terminal of the eighth resistor is connected to the second terminal of the third capacitor and grounded. The inverting input of the comparator is connected to the second terminal of the fifth resistor. The second terminal of the sixth resistor, the first terminal of the second resistor, and the output terminal of the comparator are connected. An over / under voltage monitoring waveform signal is output through the output terminal of the comparator. The second terminal of the second resistor is connected to the preset power supply.

[0014] In some alternative implementations, the output circuit further includes a filter circuit, and the output of the comparator circuit is connected to the control terminal through the filter circuit. The filter circuit is used to filter the over / under voltage monitoring waveform signal.

[0015] In some optional implementations, the input circuit includes a first transistor, a fourth resistor, a ninth resistor, a tenth resistor, a fourteenth resistor, and a fifteenth resistor. The first terminal of the fourteenth resistor is connected to the first terminal of the fourth resistor and the output terminal of the rectifier circuit. The second terminal of the fourteenth resistor is connected to the base of the first transistor through the fifteenth resistor. The second terminal of the fourth resistor is connected to the first terminal of the ninth resistor and the first input terminal of the optocoupler. The second terminal of the ninth resistor is connected to the first terminal of the tenth resistor and the collector of the first transistor. The second terminal of the tenth resistor is connected to the second input terminal of the optocoupler. The emitter of the first transistor is grounded.

[0016] In some alternative implementations, the input circuit also includes a Zener diode, with its anode grounded and its cathode connected to the second terminal of the fourteenth resistor.

[0017] In some alternative implementations, the input circuit further includes a voltage regulator, a seventh resistor, an eleventh resistor, and a fourth capacitor. The anode of the voltage regulator is grounded, the cathode of the voltage regulator is connected to the second terminal of the fourteenth resistor, the reference stage of the voltage regulator is connected to the first terminal of the fourth capacitor, the first terminal of the eleventh resistor, and the first terminal of the seventh resistor, respectively. The second terminal of the fourth capacitor and the second terminal of the eleventh resistor are connected to and grounded, and the second terminal of the seventh resistor is connected to the first terminal of the fourth resistor.

[0018] In some alternative implementations, the input circuit further includes a seventeenth resistor and a fifth capacitor, with the first terminal of the seventeenth resistor connected to the second terminal of the fourteenth resistor, the second terminal of the seventeenth resistor grounded, and the fifth capacitor and the seventeenth resistor connected in parallel.

[0019] Secondly, this utility model provides a PIM module, including the over / under voltage protection circuit of any one of the first aspects of this utility model.

[0020] The beneficial effects of this utility model are:

[0021] This utility model discloses an over / under voltage protection circuit and a PIM module. By adding an input circuit, an output circuit, and an optocoupler to the PIM module, the input circuit adjusts the turn-on angle of the phototransistor on the output side of the optocoupler according to the input voltage. The output circuit generates an over / under voltage monitoring waveform signal based on the turn-on angle of the phototransistor on the output side of the optocoupler and outputs the over / under voltage monitoring waveform signal to the control terminal. This enables real-time monitoring of the input voltage over / under voltage state, effectively preventing damage to the PIM module and related circuits caused by abnormal input voltage, and improving the stability and reliability of the PIM module. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a block diagram illustrating the principle of the PIM module in related technologies;

[0024] Figure 2 This is a circuit diagram of the over / under voltage protection circuit in an embodiment of this utility model;

[0025] Figure 3 This is a schematic diagram of the PIM module in an embodiment of this utility model;

[0026] Explanation of reference numerals in the attached figures:

[0027] 100. Input circuit; 200. Output circuit; 201. Charging / discharging circuit; 202. Comparator circuit; 203. Filter circuit; R1. First resistor; R2. Second resistor; R3. Third resistor; R4. Fourth resistor; R5. Fifth resistor; R6. Sixth resistor; R7. Seventh resistor; R8. Eighth resistor; R9. Ninth resistor; R10. Tenth resistor; R11. Eleventh resistor; R12. Twelfth resistor; R14. Fourteenth resistor; R15. Fifteenth resistor; R17. Seventeenth resistor; C1. First capacitor; C2. Second capacitor; C3. Third capacitor; C4. Fourth capacitor; C5. Fifth capacitor; C6. Sixth capacitor; BR1. Optocoupler; Q1. First transistor; Z1. Zener diode; U3. Zener diode; U1B. Comparator. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] In the description of this utility model, it should be noted that the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 2As shown, an over / under voltage protection circuit of this utility model is applied to a PIM module and includes an input circuit 100, an output circuit 200, and an optocoupler BR1.

[0033] The input terminal of the input circuit 100 is connected to the output terminal of the rectifier circuit in the PIM module, and the input voltage is received through the output terminal of the rectifier circuit. The output terminal of the input circuit 100 is connected to the optocoupler BR1. The input circuit 100 is used to adjust the turn-on angle of the phototransistor on the output side of the optocoupler BR1 according to the input voltage.

[0034] The input terminal of the output circuit 200 is connected to the optocoupler BR1 and the output terminal. The output circuit 200 is used to generate an over / under voltage monitoring waveform signal based on the turn-on angle of the phototransistor on the output side of the optocoupler BR1, and output the over / under voltage monitoring waveform signal to the control terminal.

[0035] Specifically, the optocoupler BR1 includes a light-emitting diode and a phototransistor. The input terminals of the optocoupler BR1 include a first input terminal and a second output terminal, which are the anode and cathode of the light-emitting diode, respectively. The output terminals of the optocoupler BR1 include a first output terminal and a second output terminal, which are the collector and emitter of the phototransistor, respectively.

[0036] The input circuit 100 receives the input voltage from the rectifier circuit in the PIM module, performs voltage regulation and current amplification on the input voltage, and then inputs it to the optocoupler BR1. The turn-on angle of the phototransistor on the output side of the optocoupler BR1 is adjusted. The larger the input voltage, the larger the turn-on angle of the phototransistor.

[0037] The output circuit 200 generates an over / under voltage monitoring waveform signal based on the turn-on angle of the phototransistor. This signal changes with the turn-on angle of the phototransistor; a larger turn-on angle results in a larger duty cycle, meaning a larger input voltage corresponds to a larger duty cycle. The output circuit 200 outputs this undervoltage monitoring waveform signal to the control terminal. The control terminal can determine whether the PIM module has experienced overvoltage or undervoltage based on the duty cycle of the undervoltage monitoring waveform signal, thus enabling monitoring of the input voltage over / undervoltage.

[0038] The control terminal includes a microcontroller unit (MCU) and / or an IGBT driver. The control terminal is configured according to the actual application scenario of the PIM module in this embodiment. For example, if the PIM module is used for motor driving, when the control terminal detects that the duty cycle of the over / under voltage monitoring waveform signal is greater than the overvoltage setting or less than the undervoltage setting, the IGBT driver stops working, the MCU stops outputting PWM, and simultaneously the MCU outputs a low-level signal to the relay drive signal, preventing the relay from operating and avoiding damage to the motor and the PIM module.

[0039] This utility model provides an over / under voltage protection circuit by adding an input circuit 100, an output circuit 200, and an optocoupler BR1 to a PIM module. The input circuit 100 adjusts the turn-on angle of the phototransistor on the output side of the optocoupler BR1 according to the input voltage. The output circuit 200 generates an over / under voltage monitoring waveform signal based on the turn-on angle of the phototransistor on the output side of the optocoupler BR1 and outputs the over / under voltage monitoring waveform signal to the control terminal. This achieves real-time monitoring of the input voltage over / under voltage state, effectively preventing damage to the PIM module and related circuits due to abnormal input voltage, and improving the stability and reliability of the PIM module.

[0040] In some embodiments, the output circuit 200 includes a charging and discharging circuit 201 and a comparator circuit 202. The input terminal of the charging and discharging circuit 201 is connected to the output terminal of the optocoupler BR1, the output terminal of the charging and discharging circuit 201 is connected to the input terminal of the comparator circuit 202, and the output terminal of the comparator circuit 202 is connected to the control terminal.

[0041] The charging and discharging circuit 201 is used to output a comparison voltage signal according to the turn-on angle of the phototransistor on the output side of the optocoupler BR1. The duration of the comparison voltage signal being less than a preset voltage value is positively correlated with the magnitude of the turn-on angle of the phototransistor on the output side of the optocoupler BR1.

[0042] The comparator circuit 202 is used to output an over / under voltage monitoring waveform signal based on the comparison voltage signal.

[0043] Through the charging and discharging circuit 201 and the comparator circuit 202, an over- and under-voltage monitoring waveform signal with an adjustable duty cycle can be output based on the turn-on angle of the phototransistor, i.e. the magnitude of the input voltage, so that the control terminal can easily judge over-voltage and under-voltage.

[0044] Specifically, the charging and discharging circuit 201 includes a first capacitor C1, a second capacitor C2, a third resistor R3, and a fifth resistor R5. The first end of the third resistor R3 is connected to the first output end of the optocoupler BR1, the first end of the first capacitor C1, and the first end of the fifth resistor R5, respectively. The second end of the third resistor R3 is connected to a preset power supply. The second end of the first capacitor C1 is connected to the second output end of the optocoupler BR1 and the first end of the second capacitor C2, respectively, and grounded. The second end of the fifth resistor R5 is connected to the second end of the second capacitor C2 and the input end of the comparator circuit 202, respectively.

[0045] The optocoupler BR1 has a first output terminal and a second output terminal, which are the collector and emitter of the phototransistor, respectively. When the turn-on angle of the phototransistor decreases, the preset power supply charges the second capacitor C2. During one charge-discharge cycle, the duration for which the voltage of the second capacitor C2 is less than or equal to the set comparison voltage (0.1V) also decreases accordingly. Therefore, the magnitude of the input voltage can be determined based on this.

[0046] The comparator circuit 202 includes a comparator U1B, a first resistor R1, a second resistor R2, a sixth resistor R6, an eighth resistor R8, and a third capacitor C3. The non-inverting input of the comparator U1B is connected to the first terminals of the first resistor R1, the eighth resistor R8, the third capacitor C3, and the sixth resistor R6, respectively. The second terminal of the first resistor R1 is connected to a preset power supply. The second terminal of the eighth resistor R8 is connected to the second terminal of the third capacitor C3 and grounded. The inverting input of the comparator U1B is connected to the second terminal of the fifth resistor R5. The second terminal of the sixth resistor R6 and the first terminal of the second resistor R2 are connected to the output terminal of the comparator U1B. The over / under voltage monitoring waveform signal is output through the output terminal of the comparator U1B. The second terminal of the second resistor R2 is connected to the preset power supply.

[0047] The sixth resistor, R6, is a positive feedback resistor. Even if the input voltage fluctuates slightly at the overvoltage point, comparator U1B will not reverse, thus achieving undervoltage latching. Specifically, when the voltage at the inverting input of comparator U1B is below 0.1V, the output voltage of comparator U1B is high. Due to the effect of the sixth resistor R6, the non-inverting input is pulled high to above 0.1V (e.g., 0.2V), achieving undervoltage latching. Only when the voltage at the inverting input exceeds the latching voltage (0.2V) will comparator U1B reverse. This prevents false undervoltage fault reports when the input voltage fluctuates at the overvoltage point.

[0048] In some embodiments, the output circuit 200 further includes a filter circuit 203. The output terminal of the comparison circuit 202 is connected to the control terminal through the filter circuit 203. The filter circuit 203 is used to filter the over- and under-voltage monitoring waveform signal.

[0049] Specifically, the filter circuit 203 includes a twelfth resistor R12 and a sixth capacitor C6. The first end of the twelfth resistor R12 is connected to the output terminal of the comparator U1B, the second end of the twelfth resistor R12 is connected to the first end of the sixth capacitor C6 and the control terminal, and the second end of the sixth capacitor C6 is grounded.

[0050] Adding a filter circuit 203 to the output circuit 200 to filter the undervoltage monitoring waveform signal output by the comparator circuit 202 can effectively remove noise and interference components from the signal, making the signal input to the control terminal more stable, improving the accuracy of the control terminal in judging over- and under-voltage states, and reducing the possibility of misjudgment.

[0051] In some embodiments, the input circuit 100 includes a first transistor Q1, a fourth resistor R4, a ninth resistor R9, a tenth resistor R10, a fourteenth resistor R14, and a fifteenth resistor R15. The first end of the fourteenth resistor R14 is connected to the first end of the fourth resistor R4 and the output end of the rectifier circuit. The second end of the fourteenth resistor R14 is connected to the base of the first transistor Q1 through the fifteenth resistor R15. The second end of the fourth resistor R4 is connected to the first end of the ninth resistor R9 and the first input end of the optocoupler BR1. The second end of the ninth resistor R9 is connected to the first end of the tenth resistor R10 and the collector of the first transistor Q1. The second end of the tenth resistor R10 is connected to the second input end of the optocoupler BR1. The emitter of the first transistor Q1 is grounded.

[0052] Specifically, the base current, i.e. the current on the input side of the optocoupler BR1, is amplified by the first transistor Q1.

[0053] The first transistor Q1, the fourth resistor R4, the ninth resistor R9, the tenth resistor R10, the fourteenth resistor R14, and the fifteenth resistor R15 work together to accurately adjust the current on the input side of the optocoupler BR1 according to the input voltage output by the rectifier circuit, thereby controlling the turn-on angle of the optocoupler BR1 output side phototransistor, providing a basis for subsequent over- and under-voltage monitoring.

[0054] In some embodiments, the input circuit 100 further includes a Zener diode Z1, the anode of which is grounded, and the cathode of which is connected to the second end of the fourteenth resistor R14.

[0055] The rated voltage across the Zener diode Z1 is 15V. Its function is to stabilize the voltage across the base and emitter of the first transistor Q1 within 15V, preventing damage to the first transistor Q1 due to excessive input voltage. This protects the transistor and improves the stability and reliability of the input circuit 100.

[0056] In some embodiments, the input circuit 100 further includes a voltage regulator U3, a seventh resistor R7, an eleventh resistor R11, and a fourth capacitor C4. The anode of the voltage regulator U3 is grounded, the cathode of the voltage regulator U3 is connected to the second terminal of the fourteenth resistor R14, the reference terminal of the voltage regulator U3 is connected to the first terminal of the fourth capacitor C4, the first terminal of the eleventh resistor R11, and the first terminal of the seventh resistor R7, respectively. The second terminal of the fourth capacitor C4 is connected to the second terminal of the eleventh resistor R11 and grounded, and the second terminal of the seventh resistor R7 is connected to the first terminal of the fourth resistor R4.

[0057] Specifically, voltage regulator U3 ensures stable voltage at the base of the first transistor Q1, providing stable operating conditions for the transistor. Resistors R7 (seventh), R11 (eleventh), and C4 (fourth) work together to filter and stabilize the voltage, further improving the stability and anti-interference capability of the input circuit 100 and facilitating more accurate adjustment of the turn-on angle of optocoupler BR1.

[0058] In some embodiments, the input circuit 100 further includes a seventeenth resistor R17 and a fifth capacitor C5, the first end of the seventeenth resistor R17 and the second end of the fourteenth resistor R14 are connected, the second end of the seventeenth resistor R17 is grounded, and the fifth capacitor C5 and the seventeenth resistor R17 are connected in parallel.

[0059] The seventeenth resistor R17 and the fifth capacitor C5 can filter and stabilize the voltage, removing high-frequency noise and interference signals from the input voltage, making the voltage input to subsequent circuits more stable.

[0060] The working principle of the over / under voltage protection circuit is as follows:

[0061] When the input voltage AC is low, i.e. below the undervoltage point, the current flowing into the fifteenth resistor R15 is low, resulting in a low turn-on angle of the phototransistor in optocoupler BR1. Consequently, the voltage at the second capacitor C2 is less than or equal to the set comparison voltage for less than half a cycle within one cycle. The set comparison voltage can be set to 0.1V. At this time, the voltage at the non-inverting input of comparator U1B is 0.1V. The over / undervoltage monitoring waveform signal output by comparator U1B is a square wave with a duty cycle of <50% within one cycle. Then, the over / undervoltage monitoring waveform signal is input to the MCU, and the MCU determines that there is an input undervoltage fault.

[0062] When the input voltage AC is within the normal voltage range, the current flowing into the fifteenth resistor R15 is slightly larger, the turn-on angle of the phototransistor in optocoupler BR1 is appropriate, and the duration of the voltage at the second capacitor C2 being less than or equal to the set comparison voltage is between 0.5 and 0.8 cycles. The voltage at the non-inverting input of comparator U1B is 0.1V. At this time, the over / under voltage monitoring waveform signal output by the output of comparator U1B is a square wave within one cycle, with a duty cycle between 50% and 80%. This over / under voltage monitoring waveform signal is input to the MCU, and the MCU determines that there is no fault.

[0063] When the input voltage AC is large, i.e. below the overvoltage point, the current flowing into the fifteenth resistor R15 is large, the turn-on angle of the phototransistor in optocoupler BR1 is large, the voltage at the second capacitor C2 is less than or equal to the set comparison voltage for a duration greater than 0.8 cycles, the voltage at the non-inverting input of comparator U1B is 0.1V, and the over / undervoltage monitoring waveform signal output by the output of comparator U1B at this time is a square wave with a duty cycle >80% within one cycle. This over / undervoltage monitoring waveform signal is input to the MCU, and the MCU judges it as an input overvoltage fault.

[0064] This utility model embodiment also provides a PIM module, including any of the over / under voltage protection circuits in the above embodiments of this utility model.

[0065] This utility model embodiment also provides a PIM module, including the over / under voltage protection circuit as in any of the above embodiments.

[0066] Among them, such as Figure 3 As shown, the PIM module also includes a rectifier circuit, an inverter circuit, a brake circuit, and a temperature protection circuit. The rectifier circuit converts three-phase AC power into DC power, and the inverter circuit converts DC power into AC power to drive loads such as motors and compressors. The temperature protection circuit samples the internal module temperature to prevent the module from being damaged due to overheating.

[0067] In a PIM module application scenario, the external circuit of the PIM module also includes a relay RY2, a thin film capacitor C25, and a control terminal (not shown in the figure). The input signal of the relay comes from the control terminal. P1 is the input pin of the inverter circuit. The output pin P of the rectifier circuit is connected to the input terminal of the input circuit 100, and receives the input voltage AC in sequence.

[0068] When the input AC voltage exceeds the overvoltage or undervoltage point, the overvoltage and undervoltage protection circuit will send the overvoltage and undervoltage monitoring waveform signal to the control terminal, such as the MCU and IGBT driver. The IGBT driver will stop working, the MCU will stop outputting the PWM signal, and at the same time the MCU will output a low level to the relay, so the relay will not work, thus avoiding damage to the motor and PIM module.

[0069] When the module temperature is too high, the temperature protection circuit uses an NTC temperature sensor circuit. The NTC temperature sensor circuit sends the over-temperature signal to the MCU, the MCU stops outputting the PWM signal, and the motor stops working.

[0070] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and all such modifications and variations fall within the scope of protection.

Claims

1. An over / under voltage protection circuit, applied to a PIM module, characterized in that, Includes input circuitry, output circuitry, and optocouplers; The input terminal of the input circuit is connected to the output terminal of the rectifier circuit in the PIM module, and the input voltage is received through the output terminal of the rectifier circuit. The output terminal of the input circuit is connected to the optocoupler, and the input circuit is used to adjust the turn-on angle of the phototransistor on the output side of the optocoupler according to the input voltage. The input terminal of the output circuit is connected to the output terminal of the optocoupler. The output circuit is used to generate an over / under voltage monitoring waveform signal based on the turn-on angle of the phototransistor on the output side of the optocoupler, and output the over / under voltage monitoring waveform signal to the control terminal.

2. The over / under voltage protection circuit according to claim 1, characterized in that, The output circuit includes a charging / discharging circuit and a comparator circuit. The input terminal of the charging / discharging circuit is connected to the output terminal of the optocoupler, the output terminal of the charging / discharging circuit is connected to the input terminal of the comparator circuit, and the output terminal of the comparator circuit is connected to the control terminal. The charging and discharging circuit is used to output a comparison voltage signal according to the turn-on angle of the phototransistor on the output side of the optocoupler. The duration of the comparison voltage signal being less than a preset voltage value is positively correlated with the magnitude of the turn-on angle of the phototransistor on the output side of the optocoupler. The comparison circuit is used to output the over / under voltage monitoring waveform signal based on the comparison voltage signal.

3. The over / under voltage protection circuit according to claim 2, characterized in that, The charging and discharging circuit includes a first capacitor, a second capacitor, a third resistor, and a fifth resistor. The first end of the third resistor is connected to the first output terminal of the optocoupler, the first end of the first capacitor, and the first end of the fifth resistor, respectively. The second end of the third resistor is connected to a preset power supply. The second end of the first capacitor is connected to the second output terminal of the optocoupler and the first end of the second capacitor, respectively, and grounded. The second end of the fifth resistor is connected to the second end of the second capacitor and the input terminal of the comparator circuit, respectively.

4. The over / under voltage protection circuit according to claim 3, characterized in that, The comparison circuit includes a comparator, a first resistor, a second resistor, a sixth resistor, an eighth resistor, and a third capacitor. The non-inverting input of the comparator is connected to the first terminal of the first resistor, the first terminal of the eighth resistor, the first terminal of the third capacitor, and the first terminal of the sixth resistor. The second terminal of the first resistor is connected to the preset power supply. The second terminal of the eighth resistor is connected to the second terminal of the third capacitor and grounded. The inverting input of the comparator is connected to the second terminal of the fifth resistor. The second terminal of the sixth resistor is connected to the first terminal of the second resistor and the output terminal of the comparator. The over / under voltage monitoring waveform signal is output through the output terminal of the comparator. The second terminal of the second resistor is connected to the preset power supply.

5. The over / under voltage protection circuit according to claim 2, characterized in that, The output circuit further includes a filtering circuit. The output terminal of the comparator circuit is connected to the control terminal through the filtering circuit. The filtering circuit is used to filter the over / under voltage monitoring waveform signal.

6. The over / under voltage protection circuit according to claim 1, characterized in that, The input circuit includes a first transistor, a fourth resistor, a ninth resistor, a tenth resistor, a fourteenth resistor, and a fifteenth resistor. The first end of the fourteenth resistor is connected to the first end of the fourth resistor and the output end of the rectifier circuit. The second end of the fourteenth resistor is connected to the base of the first transistor through the fifteenth resistor. The second end of the fourth resistor is connected to the first end of the ninth resistor and the first input end of the optocoupler. The second end of the ninth resistor is connected to the first end of the tenth resistor and the collector of the first transistor. The second end of the tenth resistor is connected to the second input end of the optocoupler. The emitter of the first transistor is grounded.

7. The over / under voltage protection circuit according to claim 6, characterized in that, The input circuit also includes a Zener diode, the anode of which is grounded, and the cathode of which is connected to the second end of the fourteenth resistor.

8. The over / under voltage protection circuit according to claim 6, characterized in that, The input circuit also includes a voltage regulator, a seventh resistor, an eleventh resistor, and a fourth capacitor. The anode of the voltage regulator is grounded, the cathode of the voltage regulator is connected to the second terminal of the fourteenth resistor, the reference stage of the voltage regulator is connected to the first terminal of the fourth capacitor, the first terminal of the eleventh resistor, and the first terminal of the seventh resistor, respectively. The second terminal of the fourth capacitor is connected to the second terminal of the eleventh resistor and grounded, and the second terminal of the seventh resistor is connected to the first terminal of the fourth resistor.

9. The over / under voltage protection circuit according to claim 6, characterized in that, The input circuit also includes a seventeenth resistor and a fifth capacitor. The first end of the seventeenth resistor is connected to the second end of the fourteenth resistor, the second end of the seventeenth resistor is grounded, and the fifth capacitor and the seventeenth resistor are connected in parallel.

10. A PIM module, characterized in that, Includes the over / under voltage protection circuit as described in any one of claims 1 to 9.

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