CN-224218110-U - Overload protection circuit of power module

CN224218110UCN 224218110 UCN224218110 UCN 224218110UCN-224218110-U

Abstract

The utility model relates to the technical field of power modules, in particular to an overload protection circuit of a power module, which comprises a main control chip, a power module, a sampling circuit and a protection circuit which are electrically connected in sequence, wherein the sampling circuit comprises a voltage dividing unit, a filtering unit, an isolating unit and an amplifying unit which are electrically connected in sequence, the amplifying unit outputs a detection value, the protection circuit outputs an overcurrent signal based on the detection value and a set value, the overcurrent signal is output into the main control chip, and the main control chip judges the state of the power module according to the overcurrent signal. In the utility model, the sampling circuit accurately detects the working state of the power module, the protection circuit compares the working state based on the accurate detection value and the set value, once the detection value exceeds the set value, the over-current signal can be rapidly output and self-locked until the main control chip sends out a reset signal or presses the key S by people, the whole circuit has compact and reasonable structural design, and each unit has definite and cooperative work in division, lower cost and stronger practicability.

Inventors

Wang Qindang
HU ZHIPING
WANG XUEHE

Assignees

江苏芯华睿微电子有限公司

Dates

Publication Date: 20260508
Application Date: 20250526

Claims (6)

1. The overload protection circuit of the power module comprises a main control chip (1), the power module (2), a sampling circuit (3) and a protection circuit (4) which are electrically connected in sequence, and is characterized in that the sampling circuit (3) comprises a voltage dividing unit, a filtering unit, an isolating unit and an amplifying unit which are electrically connected in sequence, the amplifying unit outputs a detection value, the protection circuit (4) outputs an overcurrent signal based on the detection value and a set value, the overcurrent signal is output into the main control chip (1), and the main control chip (1) judges the state of the power module (2) according to the overcurrent signal.
2. The overload protection circuit of a power module according to claim 1, wherein the voltage dividing unit comprises a resistor R1 and a resistor R2, the resistor R1 is connected in series in a line at one end of a collector of the power module (2), a second end of the resistor R1 is connected with the collector of the power module (2), a first end of the resistor R2 is connected with a second end of the resistor R1, and a second end of the resistor R2 is grounded.
3. The overload protection circuit of the power module as set forth in claim 2, wherein the filter unit comprises a resistor R3 and a capacitor C1, the first end of the resistor R3 is connected to the second end of the resistor R1, the second end of the resistor R3 is connected to the first end of the capacitor C1, and the second end of the capacitor C1 is grounded.
4. The overload protection circuit of the power module as set forth in claim 3, wherein the isolation unit comprises a voltage follower U1, the non-inverting input of the voltage follower U1 is connected with the second end of the resistor R3, and the inverting input of the voltage follower U1 is connected with the output end of the voltage follower U1.
5. The overload protection circuit of the power module of claim 4, wherein the amplifying unit comprises a resistor R4, a resistor R5, a resistor R6 and an operational amplifier U2, the first end of the resistor R4 is connected with the output end of the voltage follower U1, the second end of the resistor R4 is connected with the in-phase input end of the operational amplifier U2, the first end of the resistor R5 is connected with the inverting input end of the operational amplifier U2, the second end of the resistor R5 is connected with the output end of the operational amplifier U2, the first end of the resistor R6 is connected with the inverting input end of the operational amplifier U2, the second end of the resistor R6 is grounded, and the operational amplifier U2 outputs the detection value.
6. The overload protection circuit of a power module of claim 5, wherein: the protection circuit (4) comprises a power supply VCC, a resistor R7, a resistor R8, a voltage comparator U3, a resistor R9, a NAND gate U4, a resistor R10, a resistor R11, a triode Q1, a triode Q2, a resistor R12, a capacitor C2, a resistor R13, a resistor R14, a triode Q3, a key S, a resistor R15, a resistor R16 and a resistor R17, wherein the triode Q1, the triode Q2 and the triode Q3 are NPN type triodes, the first end of the resistor R7 is connected with the power supply VCC, the second end of the resistor R7 is connected with the non-inverting input end of the voltage comparator U3, the first end of the resistor R8 is connected with the second end of the resistor R7, the second end of the resistor R8 is grounded, the inverting input end of the voltage comparator U3 is connected with the output end of the operational amplifier U2, the output end of the voltage comparator U3 is connected with one input end of the NAND gate U4, the non-inverting input end and the inverting input end of the voltage comparator U3 respectively input a set value and a detection value, the first end of the resistor R9 is connected with the power VCC, the second end of the resistor R9 is connected with the output end of the voltage comparator U3, the first end of the resistor R10 is connected with the power VCC, the second end of the resistor R10 is connected with the collector of the triode Q2, the emitter of the triode Q2 is grounded, the first end of the resistor R11 is connected with the power VCC, the other input end of the NAND gate U4 is connected with the first end of the resistor R11, the first end of the resistor R11 is connected with the input end of the main control chip (1), the first end of the resistor R11 outputs an overcurrent signal, the second end of the resistor R11 is connected with the collector of the triode Q1, the emitter of the triode Q1 is grounded, the base of the triode Q1 is connected with the second end of the resistor R10, the output end of the NAND gate U4 is connected with the second end of the resistor R10, the first end of the resistor R12 is connected with the first end of the resistor R12, the second end of the capacitor C2 is grounded, the first end of the resistor R13 is connected with the output port of the main control chip (1), the second end of the resistor R13 is connected with the base electrode of the triode Q3, the first end of the resistor R14 is connected with the base electrode of the triode Q3, the second end of the resistor R14 is connected with the emitting electrode of the triode Q3, the collecting electrode of the triode Q3 is connected with the first end of the resistor R17, the second end of the resistor R17 is grounded, the first end of the key S is connected with the collecting electrode of the triode Q3, the second end of the key S is connected with the emitting electrode of the triode Q3, the first end of the resistor R15 is connected with the second end of the key S, the second end of the resistor R15 is connected with the base electrode of the triode Q2, the first end of the resistor R16 is connected with the second end of the resistor R15, and the second end of the resistor R16 is grounded.

Description

Overload protection circuit of power module Technical Field The utility model relates to the technical field of power modules, in particular to an overload protection circuit of a power module. Background In modern electronic equipment and power systems, a power module is used as a key component and is widely applied to various fields of industrial automation, new energy automobiles, smart grids and the like, and the power module bears important tasks of electric energy conversion and power amplification, and the running stability and reliability of the power module are directly related to the performance and safety of the whole system. However, the actual running environment is extremely complex, the power module always faces overload risks, on one hand, abrupt changes of loads are common in industrial production scenes, such as starting and stopping of a motor, and frequent opening and closing of large equipment can lead to large increase of instantaneous current and enable the power module to bear loads exceeding a rated range, on the other hand, circuit faults such as short circuit, poor grounding and the like can lead to abnormal increase of working current of the power module, if overload conditions cannot be effectively treated in time, performance of semiconductor devices inside the power module can be reduced due to overheating, long-term accumulation can cause permanent damage, system faults are caused, production stagnation and equipment damage are caused, and personnel safety is even compromised. Some advanced protection circuits introduce electronic detection and control technology, but have the problems of complex circuit structure and high cost, and the complex circuits not only increase the difficulty of design and debugging, but also increase the product cost, thereby limiting the popularization of the protection circuits in application scenes sensitive to the cost. Disclosure of utility model The present utility model is directed to an overload protection circuit for a power module, so as to solve the problems set forth in the background art. In order to achieve the above purpose, the present utility model provides the following technical solutions: The overload protection circuit of the power module comprises a main control chip, a power module, a sampling circuit and a protection circuit which are electrically connected in sequence, wherein the sampling circuit comprises a voltage dividing unit, a filtering unit, an isolating unit and an amplifying unit which are electrically connected in sequence, the amplifying unit outputs a detection value, the protection circuit outputs an overcurrent signal based on the detection value and a set value, the overcurrent signal is output into the main control chip, and the main control chip judges the state of the power module according to the overcurrent signal. Preferably, the voltage dividing unit includes a resistor R1 and a resistor R2, the resistor R1 is connected in series with a line at one end of a collector of the power module (2), a second end of the resistor R1 is connected with the collector of the power module (2), a first end of the resistor R2 is connected with a second end of the resistor R1, and a second end of the resistor R2 is grounded. Preferably, the filter unit includes a resistor R3 and a capacitor C1, where a first end of the resistor R3 is connected to a second end of the resistor R1, a second end of the resistor R3 is connected to a first end of the capacitor C1, and a second end of the capacitor C1 is grounded. Preferably, the isolation unit includes a voltage follower U1, the non-inverting input terminal of the voltage follower U1 is connected to the second terminal of the resistor R3, and the inverting input terminal of the voltage follower U1 is connected to the output terminal of the voltage follower U1. Preferably, the amplifying unit includes a resistor R4, a resistor R5, a resistor R6, and an operational amplifier U2, where a first end of the resistor R4 is connected to an output end of the voltage follower U1, a second end of the resistor R4 is connected to an in-phase input end of the operational amplifier U2, a first end of the resistor R5 is connected to an inverting input end of the operational amplifier U2, a second end of the resistor R5 is connected to an output end of the operational amplifier U2, a first end of the resistor R6 is connected to an inverting input end of the operational amplifier U2, a second end of the resistor R6 is connected to the ground, and the operational amplifier U2 outputs a detection value. Preferably, the protection circuit comprises a power supply VCC, a resistor R7, a resistor R8, a voltage comparator U3, a resistor R9, a NAND gate U4, a resistor R10, a resistor R11, a triode Q1, a triode Q2, a resistor R12, a capacitor C2, a resistor R13, a resistor R14, a triode Q3, a key S, a resistor R15, a resistor R16 and a resistor R17, wherein the triode Q1, the triode Q2 and the triode