Driving circuit of power device
By designing a power device driving circuit containing a soft shutdown circuit, the problem of inability to effectively protect power devices in the overcurrent state in the prior art is solved, and the soft shutdown and safety improvement of power devices is achieved.
Patent Information
- Application Number
- CN202420614030.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-27
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2034-03-27
AI Technical Summary
The existing power device driving circuit cannot effectively protect power devices in the overcurrent state, resulting in device damage and equipment safety and reliability affected.
A power device driving circuit including a first signal isolation circuit, a push-pull circuit, a voltage stabilization circuit, a second signal isolation circuit and a soft shutdown circuit are designed. When the soft shutdown circuit receives an overcurrent fault signal, it increases the loop resistance of the push-pull circuit to achieve soft shutdown of the power device.
By increasing the power device's turn-off resistance and extending the shutdown time, the electrical stress spikes of the device during overcurrent failure are reduced, the device is broken down, and the device's safety and overall safety and stability of the power electronic power converter are improved.
Smart Images
Figure CN222582287U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of power electronics, in particular to a driving circuit of a power device. Background Art
[0002] As an important device for the utilization of electric energy, power electronic power converters play an important role in production and life. The core of power electronic power converters is power semiconductor devices, which largely determine the performance of power electronic power converters. With the continuous development and market application of devices, in addition to IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) has gradually become a major branch of power devices.
[0003] Compared with IGBT, MOSFET power devices have more excellent characteristics. First, MOSFET power devices have higher switching speeds and can operate at higher junction temperatures. Second, the device can achieve high frequency, high voltage and high current at the same time. These characteristics can significantly improve the performance of semiconductor power converters, achieve higher power conversion efficiency, achieve higher power density and reduce system costs.
[0004] Power devices have a crucial impact on the stability and safety of products. Therefore, MOSFET requires a lot of protection measures, including over-temperature, over-current, over-voltage and other common protection measures. When a short circuit occurs, the current flowing through the power semiconductor device will be very large. Due to the presence of stray inductance at the moment of shutdown, an additional voltage will be added to the drain-source voltage of the power semiconductor device. The rapidly changing current will cause the MOSFET voltage to be too high and cause breakdown. In the prior art, the existing over-temperature, over-current, over-voltage and other protection circuits often cannot protect the device in the over-current state in time, causing damage to the device and causing great trouble to the safe operation and reliability of the equipment. Utility Model Content
[0005] In view of this, the utility model provides a driving circuit for a power device, the main purpose of which is to solve the technical problem that the existing power device driving circuit cannot effectively protect the power device in an overcurrent state, thereby causing the power device to be damaged due to excessive electrical stress.
[0006] To achieve the above object, the utility model first provides a driving circuit of a power device, the circuit comprising a first signal isolation circuit, a push-pull circuit, a voltage stabilizing circuit, a second signal isolation circuit and a soft shutdown circuit, wherein:
[0007] The input end of the first signal isolation circuit is connected to the output end of the power control signal, the output end of the first signal isolation circuit is connected to the input end of the push-pull circuit, the first output end of the push-pull circuit is connected to the gate of the controlled power device, and the source of the controlled power device is connected to the output end of the voltage stabilizing circuit, wherein the controlled power device is controlled by the power control signal and performs on and off operations according to the voltage between the push-pull circuit and the voltage stabilizing circuit;
[0008] The input end of the second signal isolation circuit is connected to the output end of the overcurrent fault signal, the output end of the second signal isolation circuit is connected to the input end of the soft shutdown circuit, and the output end of the soft shutdown circuit is connected to the second output end of the push-pull circuit, wherein the soft shutdown circuit is used to shut down the circuit when receiving the overcurrent fault signal to increase the loop resistance of the push-pull circuit.
[0009] Optionally, the circuit also includes a first signal input circuit, the first signal input circuit includes a first current limiting module and a first filtering module, and the first signal isolation circuit includes a first optocoupler, wherein the input end of the first current limiting module is respectively connected to the output end and the ground end of the power control signal, the output end of the first current limiting module is connected to the input end of the first filtering module, and the output end of the first filtering module is respectively connected to the anode input end and the cathode input end of the first optocoupler.
[0010] Optionally, the first current limiting module includes a first current limiting resistor and a second current limiting resistor, and the first filtering module includes a first filtering capacitor and a first filtering resistor, wherein the first current limiting resistor is connected between the output end of the power control signal and the anode input end of the first optocoupler, the second current limiting resistor is connected between the ground end and the cathode input end of the first optocoupler, and the first filtering capacitor and the first filtering resistor are connected in parallel between the anode input end and the cathode input end of the first optocoupler.
[0011] Optionally, the circuit also includes a second signal input circuit, the second signal input circuit includes a second current limiting module and a second filtering module, and the second signal isolation circuit includes a second optocoupler, wherein the input end of the second current limiting module is respectively connected to the output end and the ground end of the overcurrent fault signal, the output end of the second current limiting module is connected to the input end of the second filtering module, and the output end of the second filtering module is respectively connected to the anode input end and the cathode input end of the second optocoupler.
[0012] Optionally, the second current limiting module includes a third current limiting resistor, and the second filtering module includes a second filtering capacitor and a second filtering resistor, wherein the third current limiting resistor is connected between the ground terminal and the cathode input terminal of the second optocoupler, and the second filtering capacitor and the second filtering resistor are connected in parallel between the anode input terminal and the cathode input terminal of the second optocoupler.
[0013] Optionally, the push-pull circuit includes a driving resistor, an NPN transistor, a PNP transistor and a bias resistor, wherein the first end of the driving resistor is connected to the output end of the first signal isolation circuit, the second end of the driving resistor is respectively connected to the base of the NPN transistor and the base of the PNP transistor, the collector of the NPN transistor is connected to the positive electrode of the power supply, the emitter of the NPN transistor is respectively connected to the first end of the bias resistor and the emitter of the PNP transistor, the collector of the PNP transistor is connected to the negative electrode of the power supply through the soft shutdown circuit, and the second end of the bias resistor is connected to the gate of the controlled power device.
[0014] Optionally, the soft shutdown circuit includes a voltage stabilizing module, a protection module and a third filtering module, wherein the input end of the voltage stabilizing module is respectively connected to the positive electrode of the power supply and the negative electrode of the power supply, the output end of the voltage stabilizing module is connected to the control end of the protection module, the first end of the protection module is connected to the collector of the PNP type transistor, the second end of the protection module is connected to the negative electrode of the power supply, the input end of the third filtering module is connected to the collector of the PNP type transistor, and the output end of the third filtering module is connected to the negative electrode of the power supply.
[0015] Optionally, the voltage stabilizing module includes a Schottky diode, a pull-up resistor and a first voltage stabilizing diode, the protection module includes a field effect transistor and a protection resistor, and the third filtering module includes a third filter capacitor, wherein the first end of the pull-up resistor is connected to the positive electrode of the power supply, the second end of the pull-up resistor is respectively connected to the anode of the Schottky diode, the cathode of the first voltage stabilizing diode and the gate of the field effect transistor, the cathode of the Schottky diode is connected to the output end of the second signal isolation circuit, and the anode of the first voltage stabilizing diode is connected to the negative electrode of the power supply; the drain of the field effect transistor is connected to the collector of the PNP transistor, the source of the field effect transistor is connected to the negative electrode of the power supply, the first end of the protection resistor is connected to the collector of the PNP transistor, and the second end of the protection resistor is connected to the negative electrode of the power supply; the first end of the third filter capacitor is connected to the collector of the PNP transistor, and the second end of the third filter capacitor is connected to the negative electrode of the power supply.
[0016] Optionally, the voltage stabilizing circuit includes a voltage divider module, a support module and a fourth filter module, wherein the voltage divider module, the support module and the fourth filter module are connected in parallel between the positive pole and the negative pole of the power supply, and the output end of the voltage divider module, the output end of the support module and the output end of the fourth filter module are respectively connected to the source of the controlled power device.
[0017] Optionally, the voltage divider module includes a second voltage stabilizing diode and a voltage divider resistor, the support module includes a first support capacitor and a second support capacitor, and the fourth filter module includes a fourth filter capacitor and a fifth filter capacitor, wherein the second voltage stabilizing diode and the voltage divider resistor are connected in series between the positive pole of the power supply and the negative pole of the power supply, and the connection point between the second voltage stabilizing diode and the voltage divider resistor is connected to the source of the controlled power device; the first support capacitor and the second support capacitor are connected in series between the positive pole of the power supply and the negative pole of the power supply, and the connection point between the first support capacitor and the second support capacitor is connected to the source of the controlled power device; the fourth filter capacitor and the fifth filter capacitor are connected in series between the positive pole of the power supply and the negative pole of the power supply, and the connection point between the fourth filter capacitor and the fifth filter capacitor is connected to the source of the controlled power device.
[0018] The utility model provides a driving circuit for a power device, which can drive the controlled power device to perform on and off operations through a power control signal and the voltage between a push-pull circuit and a voltage stabilizing circuit, thereby realizing the driving of the power device. At the same time, the soft shutdown circuit added in the driving circuit can shut down the circuit when receiving an overcurrent fault signal, thereby increasing the loop resistance of the push-pull circuit. Through the above circuit, the off resistance of the power device can be increased, the off time of the power device can be extended, the off electrical stress peak of the power device can be reduced, and the soft shutdown of the power device when the power device is overcurrent can be realized, thereby avoiding the breakdown of the power device due to excessive electrical stress when a fault occurs, improving the safety of the device, and further improving the safety and stability of the power electronic power converter.
[0019] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:
[0021] Figure 1 A schematic diagram of the circuit structure of a driving circuit of a power device provided by an embodiment of the utility model is shown;
[0022] Figure 2 A schematic diagram of the circuit structure of a driving circuit of a power device provided in an embodiment of the utility model is shown. DETAILED DESCRIPTION
[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.
[0024] In order to further explain the technical means and effects adopted by the utility model to achieve the predetermined utility model purpose, the specific implementation methods, structures, features and effects of the utility model application are described in detail below in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.
[0025] Combine the following Figure 1 and Figure 2 A driving circuit of a power device according to some embodiments of the present invention is described.
[0026] In one embodiment, Figure 1 As shown, a driving circuit of a power device is provided, which includes a first signal isolation circuit 10, a push-pull circuit 20, a voltage stabilizing circuit 30, a second signal isolation circuit 40 and a soft shut-down circuit 50. The input end of the first signal isolation circuit 10 is connected to the output end of the power control signal, the output end of the first signal isolation circuit 10 is connected to the input end of the push-pull circuit 20, the first output end of the push-pull circuit 20 is connected to the gate of the controlled power device, and the source of the controlled power device is connected to the output end of the voltage stabilizing circuit 30, wherein the controlled power device is controlled by the power control signal and performs on and off operations according to the voltage between the push-pull circuit 20 and the voltage stabilizing circuit 30. Further, the input end of the second signal isolation circuit 40 is connected to the output end of the overcurrent fault signal, the output end of the second signal isolation circuit 40 is connected to the input end of the soft shut-down circuit 50, and the output end of the soft shut-down circuit 50 is connected to the second output end of the push-pull circuit 20, wherein the soft shut-down circuit 50 can be used to shut down the circuit when receiving the overcurrent fault signal to increase the loop resistance of the push-pull circuit.
[0027] In the above embodiment, the input end of the first signal isolation circuit is connected to the output end of the power control signal, the output end of the first signal isolation circuit is connected to the input end of the push-pull circuit, the first output end of the push-pull circuit is connected to the gate of the controlled power device, and the output end of the voltage stabilizing circuit is connected to the source of the controlled power device. The voltage stabilizing circuit can be used to provide stable voltage support for the power device to ensure the stability of the power device under normal working conditions; the push-pull circuit can perform on and off operations on the controlled power device according to the received power control signal and the voltage relationship between the voltage stabilizing circuit, thereby realizing the drive control of the controlled power device. Further, the input end of the second signal isolation circuit is connected to the output end of the overcurrent fault signal, the output end of the second signal isolation circuit is connected to the input end of the soft shutdown circuit, and the output end of the soft shutdown circuit is connected to the second output end of the push-pull circuit. Among them, the second signal isolation circuit can be used to receive the overcurrent fault signal and perform signal isolation, and then output the isolated signal to the soft shutdown circuit. After receiving the overcurrent fault signal, the soft shutdown circuit can shut down the circuit to increase the loop resistance of the push-pull circuit, that is, increase the shutdown resistance of the controlled power device, so that when an overcurrent fault occurs, a soft shutdown operation of the controlled power device can be implemented.
[0028] Working principle: When the circuit is working normally, after receiving the power control signal and performing signal isolation, the first signal isolation circuit outputs the control voltage through the first output end of the push-pull circuit. At this time, the soft shutdown circuit is in the on state, and the second output end of the push-pull circuit is directly connected to the negative pole of the power supply. The loop resistance of the push-pull circuit is small; when an overcurrent fault signal occurs, the soft shutdown circuit is in the off state, and the second output end of the push-pull circuit is connected to the negative pole of the power supply through the soft shutdown circuit. At this time, the loop resistance of the push-pull circuit increases, so that the off resistance of the controlled power device increases. The above circuit can suppress the problem of increased electrical stress of the power device caused by overcurrent to a certain extent, and can enable the power device to quickly achieve soft shutdown. In addition, the cost of the above circuit is low, which can effectively reduce the circuit design cost.
[0029] It should be noted that the circuit function of the driving circuit of the power device provided in this embodiment is mainly realized by the circuit connection relationship between each circuit module, and does not rely on the program module in a certain circuit module. In addition, each circuit module in the driving circuit of the power device can be realized by an analog circuit or a digital circuit, and for the circuit module that can be implanted with a program module, the realization of its module function can be realized by the program module provided by the prior art.
[0030] The driving circuit of the power device proposed in the embodiment of the utility model can drive the controlled power device to perform on and off operations through the power control signal and the voltage between the push-pull circuit and the voltage stabilizing circuit, so as to realize the driving of the power device. At the same time, the soft shutdown circuit added in the driving circuit can shut down the circuit when receiving an overcurrent fault signal, so as to increase the loop resistance of the push-pull circuit. Through the above circuit, the off resistance of the power device can be increased, the off time of the power device can be extended, the off electrical stress peak of the power device can be reduced, and the soft shutdown of the power device when the power device is overcurrent can be realized, so as to avoid the breakdown of the power device due to excessive electrical stress when a fault occurs, improve the safety of the device, and then improve the safety and stability of the power electronic power converter.
[0031] In one embodiment, the driving circuit of the power device further includes a first signal input circuit, the first signal input circuit includes a first current limiting module and a first filtering module, and the first signal isolation circuit includes a first optocoupler. The input end of the first current limiting module is respectively connected to the output end and the ground end of the power control signal, the output end of the first current limiting module is connected to the input end of the first filtering module, and the output end of the first filtering module is respectively connected to the anode input end and the cathode input end of the first optocoupler.
[0032] Specifically, the first current limiting module can be used to limit the current of the input signal to prevent damage to the optocoupler or circuit instability caused by excessive signal current. At the same time, the first current limiting module can also reduce noise interference in the circuit and improve the purity of the signal; the first filtering module can be used to filter out high-frequency noise and clutter in the input signal to ensure the accuracy and stability of the signal; the first optocoupler, as an isolation device, can effectively isolate the electrical connection between the input signal and the output signal to prevent signal distortion or malfunction due to electrical interference. This embodiment introduces a first signal input circuit, including components such as a first current limiting module, a first filtering module, and a first optocoupler, which can effectively improve the stability and reliability of the power control signal input, thereby optimizing the performance of the driving circuit of the power device.
[0033] In one embodiment, Figure 2 As shown, the first current limiting module includes a first current limiting resistor R1 and a second current limiting resistor R2, and the first filtering module includes a first filtering capacitor C1 and a first filtering resistor R3. Among them, the first current limiting resistor R1 is connected between the output end of the power control signal PWM1 and the anode input end of the first optical coupler U1, the second current limiting resistor R2 is connected between the ground terminal GND and the cathode input end of the first optical coupler U1, and the first filtering capacitor C1 and the first filtering resistor R3 are connected in parallel between the anode input end and the cathode input end of the first optical coupler U1.
[0034] Specifically, when the power control signal is output, the first current limiting module composed of the first current limiting resistor R1 and the second current limiting resistor R2 can effectively limit the current passing through the first optocoupler to prevent damage to the optocoupler or other circuit components due to excessive current. At the same time, by selecting a suitable resistance value, the first current limiting resistor R1 and the second current limiting resistor R2 can also reduce the common mode input interference signal and improve the purity of the signal. In practical applications, in order to obtain the best current limiting effect, the resistance values of R1 and R2 are usually set to be equal, for example, both are set to 180Ω. Such a design can simplify the circuit design and reduce the manufacturing cost while ensuring the current stability. Furthermore, by connecting the RC filter circuit composed of the first filter capacitor C1 and the first filter resistor R3 in parallel to the input end of the first optocoupler, the interference components in the power control signal can be effectively filtered out, and the purity and stability of the signal can be improved. The above circuit design method can ensure the stability and accuracy of the power control signal.
[0035] In one embodiment, the driving circuit of the power device further includes a second signal input circuit, the second signal input circuit includes a second current limiting module and a second filtering module, and the second signal isolation circuit includes a second optocoupler. The input end of the second current limiting module is respectively connected to the output end and the ground end of the overcurrent fault signal, the output end of the second current limiting module is connected to the input end of the second filtering module, and the output end of the second filtering module is respectively connected to the anode input end and the cathode input end of the second optocoupler.
[0036] Specifically, the second current limiting module can be used to limit the current of the input signal to prevent damage to the optocoupler or circuit instability caused by excessive signal current. At the same time, the second current limiting module can also reduce noise interference in the circuit and improve the purity of the signal; the second filtering module can be used to filter out high-frequency noise and clutter in the input signal to ensure the accuracy and stability of the signal; the second optocoupler, as an isolation device, can effectively isolate the electrical connection between the input signal and the output signal to prevent signal distortion or malfunction due to electrical interference. This embodiment introduces a second signal input circuit, including components such as a second current limiting module, a second filtering module, and a second optocoupler, which can effectively improve the stability and reliability of the overcurrent fault signal input, thereby optimizing the performance of the driving circuit of the power device.
[0037] In one embodiment, Figure 2 As shown, the second current limiting module includes a third current limiting resistor R4, and the second filtering module includes a second filtering capacitor C2 and a second filtering resistor R5. The third current limiting resistor R4 is connected between the ground terminal GND and the cathode input terminal of the second optical coupler U2, and the second filtering capacitor C2 and the second filtering resistor R5 are connected in parallel between the anode input terminal and the cathode input terminal of the second optical coupler U2.
[0038] Specifically, when the overcurrent fault signal is output, the third current limiting resistor R4 can effectively limit the current through the second optocoupler to prevent damage to the optocoupler or other circuit components due to excessive current. Furthermore, by connecting the RC filter circuit composed of the second filter capacitor C2 and the second filter resistor R5 in parallel to the input end of the second optocoupler, the interference components in the overcurrent fault signal can be effectively filtered to improve the purity and stability of the signal. The above circuit design method can ensure the stability of the overcurrent fault signal.
[0039] In one embodiment, Figure 2 As shown, the push-pull circuit includes a driving resistor R6, an NPN transistor Q1, a PNP transistor Q2 and a bias resistor R8. Among them, the first end of the driving resistor R6 is connected to the output end of the first signal isolation circuit (i.e., the first optical coupler U1), the second end of the driving resistor R6 is respectively connected to the base of the NPN transistor Q1 and the base of the PNP transistor Q2, the collector of the NPN transistor Q1 is connected to the positive electrode of the power supply +12V, the emitter of the NPN transistor Q1 is respectively connected to the first end of the bias resistor R8 and the emitter of the PNP transistor Q2, the collector of the PNP transistor Q2 is connected to the negative electrode of the power supply -12V through the soft shutdown circuit, and the second end of the bias resistor R8 is connected to the gate G of the controlled power device.
[0040] Specifically, refer to Figure 2 The working principle of the above circuit is: when the PWM signal is a high-level signal, the first optocoupler U1 is turned on, and the output end of the first optocoupler U1 outputs a high level. At this time, the NPN transistor Q1 is turned off, the PNP transistor Q2 is turned on, and the voltage between the gate G and the source S of the controlled power device is 15V, and the controlled power device is turned on; when the PWM signal is a low-level signal, the first optocoupler U1 is cut off, and the output end of the first optocoupler U1 outputs a low level. At this time, the NPN transistor Q1 is turned on, the PNP transistor Q2 is turned off, and the voltage between the gate G and the source S of the controlled power device is -9V, and the controlled power device is turned off. In this way, the drive control of the controlled power device can be achieved.
[0041] In the above embodiment, the driving resistor R6 can limit the current and stabilize the signal; the bias resistor R8 can provide a stable bias voltage for the gate of the controlled power device to ensure that the controlled power device can work normally. The above embodiment can accurately control the on and off state of the controlled power device according to the high and low levels of the PWM signal by utilizing the complementary characteristics of the NPN transistor Q1 and the PNP transistor Q2, thereby achieving accurate control of the controlled power device.
[0042] In one embodiment, the soft shutdown circuit includes a voltage stabilizing module, a protection module and a third filtering module. The input end of the voltage stabilizing module is respectively connected to the positive electrode and the negative electrode of the power supply, the output end of the voltage stabilizing module is connected to the control end of the protection module, the first end of the protection module is connected to the collector of the PNP transistor, the second end of the protection module is connected to the negative electrode of the power supply, the input end of the third filtering module is connected to the collector of the PNP transistor, and the output end of the third filtering module is connected to the negative electrode of the power supply.
[0043] Specifically, the input end of the voltage stabilizing module is connected to the positive electrode and the negative electrode of the power supply, which can ensure that a stable voltage is obtained from the power supply and output a constant voltage with small fluctuations, so that when the soft shutdown circuit does not receive an overcurrent fault signal, the protection module can be in a conductive state. At this time, the loop resistance of the push-pull circuit is small, which can enable the controlled power device to achieve rapid shutdown; when the soft shutdown circuit receives an overcurrent fault signal, the protection circuit is turned off, and the loop resistance of the push-pull circuit increases, which prolongs the shutdown time of the controlled power device and achieves a soft shutdown effect. In addition, the introduction of the third filtering module further improves the stability and reliability of the shutdown process. The soft shutdown circuit proposed in this embodiment can achieve a smooth shutdown of the controlled power device and improve the stability and safety of the entire circuit system.
[0044] In one embodiment, Figure 2 As shown, the voltage stabilizing module includes a Schottky diode D1, a pull-up resistor R7 and a first voltage stabilizing diode D2, the protection module includes a field effect transistor M1 and a protection resistor R9, and the third filtering module includes a third filtering capacitor C3. Among them, the first end of the pull-up resistor R7 is connected to the positive electrode of the power supply +12V, the second end of the pull-up resistor R7 is respectively connected to the anode of the Schottky diode D1, the cathode of the first voltage-stabilizing diode D2 and the gate of the field effect transistor M1, the cathode of the Schottky diode D1 is connected to the output end of the second signal isolation circuit (i.e., the second optical coupler U2), and the anode of the first voltage-stabilizing diode D2 is connected to the negative electrode of the power supply -12V; the drain of the field effect transistor M1 is connected to the collector of the PNP type transistor Q2, the source of the field effect transistor M1 is connected to the negative electrode of the power supply -12V, the first end of the protection resistor R9 is connected to the collector of the PNP type transistor Q2, and the second end of the protection resistor R9 is connected to the negative electrode of the power supply -12V; the first end of the third filter capacitor C3 is connected to the collector of the PNP type transistor Q2, and the second end of the third filter capacitor C3 is connected to the negative electrode of the power supply -12V.
[0045] Specifically, refer to Figure 2The working principle of the above circuit is as follows: when the soft shutdown circuit does not receive the overcurrent fault signal, the input end of the second optocoupler U2 receives a high level. At this time, the second optocoupler U2 is in the on state, the Schottky diode D1 is in the off state, and the voltage stabilizing module composed of the Schottky diode D1, the pull-up resistor R7 and the first voltage stabilizing diode D2 stabilizes the voltage between the gate and the source of the field effect tube M1 at 15V. The field effect tube M1 is turned on, and the collector of the PNP transistor in the push-pull circuit is connected to the negative pole of the power supply through the turned-on field effect tube M1. V, at this time, the loop resistance of the push-pull circuit is small; when the soft shutdown circuit receives the overcurrent fault signal, the input voltage of the second optocoupler U2 changes from a high level to a low level, and the second optocoupler U2 changes from an on state to an off state. At this time, the Schottky diode D1 is in an on state, and the voltage between the gate and the source of the field effect transistor M1 decreases, which is not enough to turn on the field effect transistor M1. The field effect transistor M1 is cut off, and the collector of the PNP transistor in the push-pull circuit is connected to the negative pole of the power supply -12V through the protection resistor R9. At this time, the loop resistance of the push-pull circuit increases.
[0046] In the above embodiment, the voltage stabilizing module can provide a stable gate voltage for the field effect tube under different working conditions, thereby controlling the conduction and cutoff of the field effect tube; the protection module can provide a smaller loop resistance for the push-pull loop in the on state, so that the controlled power device can be quickly shut down, and can provide a larger loop resistance for the push-pull loop in the cutoff state, so that the controlled power device can be slowly shut down, thereby realizing timely protection of the controlled power device; the filter capacitor can effectively filter out noise and interference signals in the circuit, ensuring the purity and stability of the voltage signal. Through the above circuit design method, the controlled power device can be smoothly shut down, and effective protection can be provided when an overcurrent fault occurs, ensuring that the circuit can achieve smooth and safe operation under normal working conditions or when an overcurrent fault occurs.
[0047] In one embodiment, the voltage stabilizing circuit includes a voltage divider module, a support module and a fourth filter module, wherein the voltage divider module, the support module and the fourth filter module are connected in parallel between the positive electrode of the power supply and the negative electrode of the power supply, and the output end of the voltage divider module, the output end of the support module and the output end of the fourth filter module are respectively connected to the source of the controlled power device.
[0048] Specifically, the voltage divider module can stably reduce the power supply voltage to the voltage range required by the controlled power device; the support module can support and stabilize the voltage in the circuit, and the module can store and release electrical energy to cope with instantaneous voltage fluctuations that may occur in the circuit; the fourth filter module can filter out high-frequency noise and interference signals in the circuit, thereby effectively reducing the noise components in the power supply voltage and improving the purity of the power supply. The stable voltage output by the three modules can directly act on the controlled power device, thereby providing it with a reliable power supply guarantee. The voltage stabilizing circuit provided in this embodiment can provide a stable and reliable power supply voltage for the controlled power device to ensure that the controlled power device can work normally.
[0049] In one embodiment, Figure 2 As shown, the voltage divider module includes a second voltage stabilizing diode D3 and a voltage divider resistor R10, the support module includes a first support capacitor C4 and a second support capacitor C6, and the fourth filter module includes a fourth filter capacitor C5 and a fifth filter capacitor C7. Among them, the second voltage stabilizing diode D3 and the voltage divider resistor R10 are connected in series between the positive electrode of the power supply +12V and the negative electrode of the power supply -12V, and the connection point of the second voltage stabilizing diode D3 and the voltage divider resistor R10 is connected to the source electrode S of the controlled power device; the first support capacitor C4 and the second support capacitor C6 are connected in series between the positive electrode of the power supply +12V and the negative electrode of the power supply -12V, and the connection point of the first support capacitor C4 and the second support capacitor C6 is connected to the source electrode S of the controlled power device; the fourth filter capacitor and the fifth filter capacitor are connected in series between the positive electrode of the power supply and the negative electrode of the power supply, and the connection point of the fourth filter capacitor C5 and the fifth filter capacitor C7 is connected to the source electrode S of the controlled power device.
[0050] Specifically, the voltage dividing module composed of the second voltage stabilizing diode D3 and the voltage dividing resistor R10 can control the voltage between the gate and the source of the controlled power device within a predetermined voltage range. Figure 2 In the circuit diagram shown, when the NPN transistor Q1 in the push-pull circuit is turned off and the PNP transistor Q2 is turned on, the voltage between the gate G and the source S of the controlled power device is 15V, and the controlled power device is turned on; when the NPN transistor Q1 in the push-pull circuit is turned on and the PNP transistor Q2 is turned off, the voltage between the gate G and the source S of the controlled power device is -9V, and the controlled power device is turned off. The support module composed of the first support capacitor C4 and the second support capacitor C6 can support the voltage signal output by the voltage divider module, and the fourth filter module composed of the fourth filter capacitor C5 and the fifth filter capacitor C7 can filter out the interference signal in the voltage signal output by the voltage divider module.
[0051] In the above embodiment, the connection point of the second voltage stabilizing diode D3 and the voltage dividing resistor R10 can output a stable voltage value, which is directly connected to the source S of the controlled power device. Through this voltage dividing method, the voltage between the gate and the source of the controlled power device can be effectively controlled within a predetermined voltage range to ensure the normal operation of the controlled power device; the support capacitors C4 and C6 can store and release electrical energy, which helps to maintain the stability of the voltage signal, especially when the circuit is subjected to instantaneous voltage fluctuations, the two support capacitors can respond quickly to ensure the stable operation of the controlled power device; the filter capacitor can effectively filter out high-frequency noise and interference components in the power supply, ensuring that the controlled power device receives a pure and stable voltage signal, thereby improving its working performance and reliability. The above circuit design method can ensure that the controlled power device can work normally and can improve the stability and reliability of the entire circuit. Specific embodiment:
[0053] In one embodiment, Figure 1 As shown, a driving circuit of a power device is provided, which includes a first signal isolation circuit 10, a push-pull circuit 20, a voltage stabilizing circuit 30, a second signal isolation circuit 40 and a soft shut-down circuit 50. The input end of the first signal isolation circuit 10 is connected to the output end of the power control signal, the output end of the first signal isolation circuit 10 is connected to the input end of the push-pull circuit 20, the first output end of the push-pull circuit 20 is connected to the gate of the controlled power device, and the source of the controlled power device is connected to the output end of the voltage stabilizing circuit 30, wherein the controlled power device is controlled by the power control signal and performs on and off operations according to the voltage between the push-pull circuit 20 and the voltage stabilizing circuit 30. Further, the input end of the second signal isolation circuit 40 is connected to the output end of the overcurrent fault signal, the output end of the second signal isolation circuit 40 is connected to the input end of the soft shut-down circuit 50, and the output end of the soft shut-down circuit 50 is connected to the second output end of the push-pull circuit 20, wherein the soft shut-down circuit 50 can be used to shut down the circuit when receiving the overcurrent fault signal to increase the loop resistance of the push-pull circuit.
[0054] In this embodiment, the driving circuit of the power device further includes a first signal input circuit, the first signal input circuit includes a first current limiting module and a first filtering module, and the first signal isolation circuit includes a first optical coupler. Figure 2As shown, the first current limiting module includes a first current limiting resistor R1 and a second current limiting resistor R2, and the first filtering module includes a first filtering capacitor C1 and a first filtering resistor R3. Among them, the first current limiting resistor R1 is connected between the output end of the power control signal PWM1 and the anode input end of the first optical coupler U1, the second current limiting resistor R2 is connected between the ground terminal GND and the cathode input end of the first optical coupler U1, and the first filtering capacitor C1 and the first filtering resistor R3 are connected in parallel between the anode input end and the cathode input end of the first optical coupler U1.
[0055] In this embodiment, the driving circuit of the power device further includes a second signal input circuit, the second signal input circuit includes a second current limiting module and a second filtering module, and the second signal isolation circuit includes a second optical coupler. Figure 2 As shown, the second current limiting module includes a third current limiting resistor R4, and the second filtering module includes a second filtering capacitor C2 and a second filtering resistor R5. The third current limiting resistor R4 is connected between the ground terminal GND and the cathode input terminal of the second optical coupler U2, and the second filtering capacitor C2 and the second filtering resistor R5 are connected in parallel between the anode input terminal and the cathode input terminal of the second optical coupler U2.
[0056] In this embodiment, if Figure 2 As shown, the push-pull circuit includes a driving resistor R6, an NPN transistor Q1, a PNP transistor Q2 and a bias resistor R8. Among them, the first end of the driving resistor R6 is connected to the output end of the first signal isolation circuit (i.e., the first optical coupler U1), the second end of the driving resistor R6 is respectively connected to the base of the NPN transistor Q1 and the base of the PNP transistor Q2, the collector of the NPN transistor Q1 is connected to the positive electrode of the power supply +12V, the emitter of the NPN transistor Q1 is respectively connected to the first end of the bias resistor R8 and the emitter of the PNP transistor Q2, the collector of the PNP transistor Q2 is connected to the negative electrode of the power supply -12V through the soft shutdown circuit, and the second end of the bias resistor R8 is connected to the gate G of the controlled power device.
[0057] In this embodiment, the soft shutdown circuit includes a voltage stabilization module, a protection module and a third filtering module. Figure 2As shown, the voltage stabilizing module includes a Schottky diode D1, a pull-up resistor R7 and a first voltage stabilizing diode D2, the protection module includes a field effect transistor M1 and a protection resistor R9, and the third filtering module includes a third filtering capacitor C3. Among them, the first end of the pull-up resistor R7 is connected to the positive electrode of the power supply +12V, the second end of the pull-up resistor R7 is respectively connected to the anode of the Schottky diode D1, the cathode of the first voltage-stabilizing diode D2 and the gate of the field effect transistor M1, the cathode of the Schottky diode D1 is connected to the output end of the second signal isolation circuit (i.e., the second optical coupler U2), and the anode of the first voltage-stabilizing diode D2 is connected to the negative electrode of the power supply -12V; the drain of the field effect transistor M1 is connected to the collector of the PNP type transistor Q2, the source of the field effect transistor M1 is connected to the negative electrode of the power supply -12V, the first end of the protection resistor R9 is connected to the collector of the PNP type transistor Q2, and the second end of the protection resistor R9 is connected to the negative electrode of the power supply -12V; the first end of the third filter capacitor C3 is connected to the collector of the PNP type transistor Q2, and the second end of the third filter capacitor C3 is connected to the negative electrode of the power supply -12V.
[0058] In this embodiment, the voltage stabilizing circuit includes a voltage dividing module, a supporting module and a fourth filtering module. Figure 2 As shown, the voltage divider module includes a second voltage stabilizing diode D3 and a voltage divider resistor R10, the support module includes a first support capacitor C4 and a second support capacitor C6, and the fourth filter module includes a fourth filter capacitor C5 and a fifth filter capacitor C7. Among them, the second voltage stabilizing diode D3 and the voltage divider resistor R10 are connected in series between the positive electrode of the power supply +12V and the negative electrode of the power supply -12V, and the connection point of the second voltage stabilizing diode D3 and the voltage divider resistor R10 is connected to the source electrode S of the controlled power device; the first support capacitor C4 and the second support capacitor C6 are connected in series between the positive electrode of the power supply +12V and the negative electrode of the power supply -12V, and the connection point of the first support capacitor C4 and the second support capacitor C6 is connected to the source electrode S of the controlled power device; the fourth filter capacitor and the fifth filter capacitor are connected in series between the positive electrode of the power supply and the negative electrode of the power supply, and the connection point of the fourth filter capacitor C5 and the fifth filter capacitor C7 is connected to the source electrode S of the controlled power device.
[0059] Working principle: When the circuit is working normally, the primary side of the optocoupler uses a PWM signal, and the secondary side of the optocoupler uses a push-pull output. At this time, the MOS tube of the soft shutdown circuit is in the on state, and the loop resistance of the push-pull circuit is small; when an overcurrent fault signal appears, the MOS tube of the soft shutdown circuit is turned off. At this time, the loop resistance of the push-pull circuit increases, which increases the off resistance of the controlled power device. The above circuit can suppress the problem of increased electrical stress of power devices caused by overcurrent to a certain extent, and can enable the power devices to quickly achieve soft shutdown. The cost of the above circuit is low, which can effectively reduce the cost of circuit design.
[0060] The driving circuit of the power device proposed in the embodiment of the utility model can drive the controlled power device to perform on and off operations through the power control signal and the voltage between the push-pull circuit and the voltage stabilizing circuit, so as to realize the driving of the power device. At the same time, the soft shutdown circuit added in the driving circuit can shut down the circuit when receiving an overcurrent fault signal, so as to increase the loop resistance of the push-pull circuit. Through the above circuit, the off resistance of the power device can be increased, the off time of the power device can be extended, the off electrical stress peak of the power device can be reduced, and the soft shutdown of the power device when the power device is overcurrent can be realized, so as to avoid the breakdown of the power device due to excessive electrical stress when a fault occurs, improve the safety of the device, and then improve the safety and stability of the power electronic power converter.
[0061] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.
Claims
1. A driving circuit for a power device, characterized in that: The circuit includes a first signal isolation circuit, a push-pull circuit, a voltage stabilization circuit, a second signal isolation circuit and a soft shutdown circuit, wherein: The input end of the first signal isolation circuit is connected to the output end of the power control signal, the output end of the first signal isolation circuit is connected to the input end of the push-pull circuit, the first output end of the push-pull circuit is connected to the gate of the controlled power device, and the source of the controlled power device is connected to the output end of the voltage stabilizing circuit, wherein the controlled power device is controlled by the power control signal and performs on and off operations according to the voltage between the push-pull circuit and the voltage stabilizing circuit; The input end of the second signal isolation circuit is connected to the output end of the overcurrent fault signal, the output end of the second signal isolation circuit is connected to the input end of the soft shutdown circuit, and the output end of the soft shutdown circuit is connected to the second output end of the push-pull circuit, wherein the soft shutdown circuit is used to shut down the circuit when receiving the overcurrent fault signal to increase the loop resistance of the push-pull circuit.
2. The driving circuit of a power device according to claim 1, characterized in that: The circuit further includes a first signal input circuit, the first signal input circuit includes a first current limiting module and a first filtering module, the first signal isolation circuit includes a first optical coupler, wherein, The input end of the first current limiting module is respectively connected to the output end and the ground end of the power control signal, the output end of the first current limiting module is connected to the input end of the first filtering module, and the output end of the first filtering module is respectively connected to the anode input end and the cathode input end of the first optocoupler.
3. The driving circuit of the power device according to claim 2, characterized in that: The first current limiting module includes a first current limiting resistor and a second current limiting resistor, and the first filtering module includes a first filtering capacitor and a first filtering resistor, wherein: The first current limiting resistor is connected between the output end of the power control signal and the anode input end of the first optocoupler, the second current limiting resistor is connected between the ground end and the cathode input end of the first optocoupler, and the first filter capacitor and the first filter resistor are connected in parallel between the anode input end and the cathode input end of the first optocoupler.
4. The driving circuit of a power device according to claim 1, characterized in that: The circuit further includes a second signal input circuit, the second signal input circuit includes a second current limiting module and a second filtering module, and the second signal isolation circuit includes a second optical coupler, wherein: The input end of the second current limiting module is respectively connected to the output end of the overcurrent fault signal and the ground end, the output end of the second current limiting module is connected to the input end of the second filtering module, and the output end of the second filtering module is respectively connected to the anode input end and the cathode input end of the second optocoupler.
5. The driving circuit of a power device according to claim 4, characterized in that: The second current limiting module includes a third current limiting resistor, and the second filtering module includes a second filtering capacitor and a second filtering resistor, wherein: The third current limiting resistor is connected between the ground terminal and the cathode input terminal of the second optocoupler, and the second filter capacitor and the second filter resistor are connected in parallel between the anode input terminal and the cathode input terminal of the second optocoupler.
6. The driving circuit of a power device according to claim 1, characterized in that: The push-pull circuit includes a driving resistor, an NPN transistor, a PNP transistor and a bias resistor, wherein: The first end of the driving resistor is connected to the output end of the first signal isolation circuit, the second end of the driving resistor is respectively connected to the base of the NPN transistor and the base of the PNP transistor, the collector of the NPN transistor is connected to the positive electrode of the power supply, the emitter of the NPN transistor is respectively connected to the first end of the bias resistor and the emitter of the PNP transistor, the collector of the PNP transistor is connected to the negative electrode of the power supply through the soft shutdown circuit, and the second end of the bias resistor is connected to the gate of the controlled power device.
7. The driving circuit of a power device according to claim 6, characterized in that: The soft shutdown circuit includes a voltage stabilization module, a protection module and a third filtering module, wherein: The input end of the voltage stabilizing module is connected to the positive electrode of the power supply and the negative electrode of the power supply respectively, the output end of the voltage stabilizing module is connected to the control end of the protection module, the first end of the protection module is connected to the collector of the PNP type transistor, the second end of the protection module is connected to the negative electrode of the power supply, the input end of the third filtering module is connected to the collector of the PNP type transistor, and the output end of the third filtering module is connected to the negative electrode of the power supply.
8. The driving circuit of a power device according to claim 7, characterized in that: The voltage stabilizing module includes a Schottky diode, a pull-up resistor and a first voltage stabilizing diode, the protection module includes a field effect transistor and a protection resistor, and the third filtering module includes a third filtering capacitor, wherein: The first end of the pull-up resistor is connected to the positive electrode of the power supply, the second end of the pull-up resistor is respectively connected to the anode of the Schottky diode, the cathode of the first voltage-stabilizing diode and the gate of the field-effect transistor, the cathode of the Schottky diode is connected to the output end of the second signal isolation circuit, and the anode of the first voltage-stabilizing diode is connected to the negative electrode of the power supply; The drain of the field effect tube is connected to the collector of the PNP transistor, the source of the field effect tube is connected to the negative electrode of the power supply, the first end of the protection resistor is connected to the collector of the PNP transistor, and the second end of the protection resistor is connected to the negative electrode of the power supply; The first end of the third filter capacitor is connected to the collector of the PNP transistor, and the second end of the third filter capacitor is connected to the negative electrode of the power supply.
9. The driving circuit of a power device according to claim 1, characterized in that: The voltage stabilizing circuit includes a voltage dividing module, a supporting module and a fourth filtering module, wherein: The voltage divider module, the support module and the fourth filter module are connected in parallel between the positive pole and the negative pole of the power supply, and the output end of the voltage divider module, the output end of the support module and the output end of the fourth filter module are respectively connected to the source of the controlled power device.
10. The driving circuit of a power device according to claim 9, characterized in that: The voltage divider module includes a second voltage stabilizing diode and a voltage divider resistor, the support module includes a first support capacitor and a second support capacitor, and the fourth filter module includes a fourth filter capacitor and a fifth filter capacitor, wherein: The second voltage stabilizing diode and the voltage dividing resistor are connected in series between the positive electrode of the power supply and the negative electrode of the power supply, and the connection point between the second voltage stabilizing diode and the voltage dividing resistor is connected to the source electrode of the controlled power device; The first supporting capacitor and the second supporting capacitor are connected in series between the positive electrode of the power supply and the negative electrode of the power supply, and a connection point between the first supporting capacitor and the second supporting capacitor is connected to the source electrode of the controlled power device; The fourth filter capacitor and the fifth filter capacitor are connected in series between the positive electrode of the power supply and the negative electrode of the power supply, and a connection point between the fourth filter capacitor and the fifth filter capacitor is connected to the source of the controlled power device.