Power device drive control circuit and system

Abstract

The present application provides a power device drive control circuit and system, the circuit comprising: a control circuit and a drive circuit; the first output end of the control circuit is connected to the first input end of the drive circuit, the second output end of the control circuit is connected to the second input end of the drive circuit, and the output end of the drive circuit is connected to the power device; the control circuit is used to output a first control signal to the drive circuit through the first output end, the first control signal is used to control the power device to turn on, and is used to output a second control signal to the drive circuit through the second output end, the second control signal is used to control the power device to turn off; the drive circuit is used to control the power device to turn on according to the first control signal, and is used to control the power device to turn off according to the second control signal. The present application is conducive to improving the reliability of power device drive control.

Description

Technical Field

[0001] The present application relates to the field of circuit technology, and in particular to a power device drive control circuit and system. Background Art

[0002] At present, in the driving control circuit of the power device, when the control circuit sends the control signal for controlling the power device to be turned on and off to the driving circuit, the control circuit usually does not transmit the control turn-on and control turn-off signals separately. The driving circuit directly controls the turning on and off of the power device according to the received control signal. If the driving circuit misses any signal when the control circuit transmits the control signal for controlling the turning on and off to the driving circuit, it will cause the driving circuit to misjudge the subsequently received signal, thereby causing the subsequent working timing of the driving circuit to be wrong and the system reliability is insufficient. Summary of the invention

[0003] The present application provides a power device drive control circuit and system, in order to improve the reliability of power device drive control.

[0004] In a first aspect, an embodiment of the present application provides a power device drive control circuit, the power device drive control circuit comprising: a control circuit and a drive circuit;

[0005] The first output end of the control circuit is connected to the first input end of the drive circuit, the second output end of the control circuit is connected to the second input end of the drive circuit, and the output end of the drive circuit is connected to a power device;

[0006] The control circuit is used to output a first control signal to the drive circuit through the first output terminal, the first control signal is used to control the power device to turn on, and is used to output a second control signal to the drive circuit through the second output terminal, the second control signal is used to control the power device to turn off;

[0007] The driving circuit is used for controlling the power device to turn on according to the first control signal, and is used for controlling the power device to turn off according to the second control signal.

[0008] Optionally, the power device drive control circuit also includes: a first isolation circuit and a second isolation circuit; the first end of the first isolation circuit is connected to the first output end of the control circuit, and the second end of the first isolation circuit is connected to the first input end of the drive circuit; the first end of the second isolation circuit is connected to the second output end of the control circuit, and the second end of the second isolation circuit is connected to the second input end of the drive circuit; the first isolation circuit and the second isolation circuit are used to isolate the control circuit and the drive circuit.

[0009] Optionally, the first isolation circuit includes: a first buffer and a first isolation transformer; the input end of the first buffer is connected to the first output end of the control circuit, the output end of the first buffer is connected to the primary coil of the first isolation transformer, and the secondary coil of the first isolation transformer is connected to the first input end of the drive circuit; the first buffer is used to power amplify the first control signal and output the first control signal after power amplification to the primary coil of the first isolation transformer.

[0010] Optionally, the second isolation circuit includes: a second buffer and a second isolation transformer; the input end of the second buffer is connected to the second output end of the control circuit, the output end of the second buffer is connected to the primary coil of the second isolation transformer, and the secondary coil of the second isolation transformer is connected to the second input end of the drive circuit; the second buffer is used to power amplify the second control signal and output the second control signal after power amplification to the primary coil of the second isolation transformer.

[0011] Optionally, the driving circuit includes: a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a resistor and a capacitor, the emitter of the first switch tube and the base of the first switch tube are combined and connected to the first output end of the control circuit, the emitter of the second switch tube, the base of the second switch tube and the first end of the capacitor are combined and connected to the collector of the first switch tube, the collector of the second switch tube and the collector of the third switch tube are combined and connected to the power device; the emitter of the fourth switch tube and the collector of the fourth switch tube are combined and connected to the second output end of the control circuit, the collector of the fourth switch tube is connected to the first end of the resistor, the second end of the resistor is connected to the collector of the third switch tube, and the emitter of the third switch tube and the second end of the capacitor are combined and grounded.

[0012] Optionally, the first buffer includes a boost circuit or a buck circuit.

[0013] Optionally, the second buffer includes a boost circuit or a buck circuit.

[0014] Optionally, the first switch tube and the second switch tube are NPN transistors.

[0015] Optionally, the control circuit is a pulse width modulation circuit, and the first control signal and the second control signal are pulse width modulation signals.

[0016] In a second aspect, the present application provides a power device drive control system, comprising any power device drive control circuit and a power device as described in the first aspect.

[0017] It can be seen that the present application provides a power device drive control circuit, including: a control circuit and a drive circuit; the first output end of the control circuit is connected to the first input end of the drive circuit, the second output end of the control circuit is connected to the second input end of the drive circuit, and the output end of the drive circuit is connected to the power device; the control circuit is used to output a first control signal to the drive circuit through the first output end, the first control signal is used to control the power device to turn on, and is used to output a second control signal to the drive circuit through the second output end, the second control signal is used to control the power device to turn off; the drive circuit is used to control the power device to turn on according to the first control signal, and is used to control the power device to turn off according to the second control signal. Since two signal transmission paths are set between the control circuit and the drive circuit, the first control signal for controlling the power device to turn on and the second control signal for controlling the power device to turn off are transmitted to the drive circuit through different transmission paths respectively, and the drive circuit can accurately control the power device to turn on according to the first control signal, and control the power device to turn off according to the second control signal, which is conducive to improving the reliability of the power device drive control. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a circuit schematic diagram of a power device drive control circuit provided by the present application;

[0019] Figure 2 is a control signal timing example diagram provided by the present application;

[0020] Figure 3 is a circuit schematic diagram of another power device drive control circuit provided by the present application;

[0021] Figure 4 is a circuit schematic diagram of another power device drive control circuit provided by the present application;

[0022] Figure 5 It is a circuit schematic diagram of a driving circuit provided in this application.

[0023] The present application is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the orientation or positional relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms of "a", "said", and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0026] Embodiment 1:

[0027] Reference Figure 1 , this embodiment provides a power device drive control circuit, the power device drive control circuit comprising: a control circuit and a drive circuit;

[0028] The first output end of the control circuit is connected to the first input end of the drive circuit, the second output end of the control circuit is connected to the second input end of the drive circuit, and the output end of the drive circuit is connected to a power device;

[0029] The control circuit is used to output a first control signal to the drive circuit through the first output terminal, the first control signal is used to control the power device to turn on, and is used to output a second control signal to the drive circuit through the second output terminal, the second control signal is used to control the power device to turn off;

[0030] The driving circuit is used for controlling the power device to turn on according to the first control signal, and is used for controlling the power device to turn off according to the second control signal.

[0031] Among them, the power device can specifically be a field effect transistor MOSFET in a switching power supply. Since the power of the control signal (including the first control signal and the second control signal) output by the control circuit is relatively small, the power device cannot be directly controlled to be turned on or off by the control signal. Therefore, a drive circuit can be set to amplify and output the control signal of the control circuit. The output end of the drive circuit can be connected to the gate of the power device. The drive circuit controls the gate voltage of the power device according to the control signal to realize the control of turning the power device on and off.

[0032] In this embodiment, the control circuit is a pulse width modulation circuit, and the first control signal and the second control signal are pulse width modulation signals.

[0033] The control timing of the first control signal and the second control signal can be specifically as follows: Figure 2 As shown, Figure 2 Two pulse width modulation signals PWM are shown in the figure, wherein PWM1 is the first control signal, the drive circuit receives PWM1 through the first input terminal, and when PWM1 is at a high level, the drive circuit controls the power device to turn on by controlling the voltage output to the gate of the power device, and PWM2 is the second control signal, the drive circuit receives PWM2 through the second input terminal, and when PWM2 is at a high level, the drive circuit controls the power device to turn off by controlling the voltage of the gate of the power device.

[0034] like Figure 2 As shown, since PWM1 is only used to control the power device to turn on, and PWM2 is only used to control the power device to turn off, compared with the control circuit and the drive circuit transmitting the control signal PWM3 for controlling the power device to turn on and the power device to turn off at the same time through only one transmission path (the high levels at different times in PWM3 are used to turn the power device on and off, for example, the first high level is used to control the power device to turn on, the second high level is used to control the power device to turn off, the third high level is used to control the power device to turn on, the fourth high level is used to turn the power device off, and so on), even if the control circuit misses any high level in PWM1, that is, the control signal for turning on, when the drive circuit receives the PWM1 high level signal through the first input terminal next time, it can still accurately control the power device to turn on (the same applies to controlling the power device to turn off according to PWM2). There will be no problem of misjudging subsequent signals due to missing one of the high levels when the PWM3 control signals for controlling the power device to be turned on and off are received simultaneously through one input terminal. For example, when the drive signal misses the high level that controls the power device to be turned on, when the next high level that controls the power device to be turned off comes, it will be mistakenly identified as a signal for controlling the power device to be turned on, which will cause the control logic of the subsequent drive circuit to be flipped and the control timing of the power device to be wrong.

[0035] Specifically, Figure 2 FIG. 4 also shows the change of the gate voltage V of the power device under the action of the first control signal PWM1 and the second control signal PWM2. Figure 2 As shown, after the first control signal PWM1 outputs a high level, the gate voltage V gradually increases, and the power device is turned on. After the second control signal PWM2 outputs a high level, the gate voltage V gradually decreases, and the power device is turned off.

[0036] It can be seen that in the embodiment of the present application, since two signal transmission paths are set between the control circuit and the driving circuit, the first control signal for controlling the power device to turn on and the second control signal for controlling the power device to turn off are respectively transmitted to the driving circuit through different transmission paths. The driving circuit can accurately control the power device to turn on according to the first control signal, and control the power device to turn off according to the second control signal, which is beneficial to improving the reliability of the power device driving control.

[0037] In this embodiment, see Figure 3 The power device driving control circuit also includes: a first isolation circuit and a second isolation circuit; the first end of the first isolation circuit is connected to the first output end of the control circuit, and the second end of the first isolation circuit is connected to the first input end of the drive circuit; the first end of the second isolation circuit is connected to the second output end of the control circuit, and the second end of the second isolation circuit is connected to the second input end of the drive circuit; the first isolation circuit and the second isolation circuit are used to isolate the control circuit and the drive circuit.

[0038] In a specific implementation, isolation circuits are respectively set in the two signal transmission paths of the control circuit and the drive circuit, which can electrically isolate the control circuit and the drive circuit to avoid mutual interference between the control circuit and the drive circuit, and can further enhance the reliability of the power device driving control circuit.

[0039] Specifically, the first isolation circuit and the second isolation circuit can be respectively provided with a transformer, and the signal isolation of the control circuit and the drive circuit is achieved by isolating the primary coil and the secondary coil of the transformer. The use of a transformer to isolate the control circuit and the drive circuit has a strong anti-interference ability in addition to voltage transmission, and electromagnetic induction can effectively ensure the safety of the circuit environment.

[0040] In this embodiment, see Figure 4 The first isolation circuit includes: a first buffer and a first isolation transformer T1; the input end of the first buffer is connected to the first output end of the control circuit, the output end of the first buffer is connected to the primary coil of the first isolation transformer T1, and the secondary coil of the first isolation transformer T1 is connected to the first input end of the drive circuit; the first buffer is used to power amplify the first control signal and output the first control signal after power amplification to the primary coil of the first isolation transformer T1.

[0041] Figure 4Port 3 of the driving circuit shown in the figure is a ground port, and ports 1 and 3 of the driving circuit together constitute a first input end of the driving circuit, connected to a first isolation transformer T1 at the output end of the first isolation circuit, and ports 2 and 3 of the driving circuit together constitute a second input end of the driving circuit, connected to a second isolation transformer T2 at the output end of the second isolation circuit. Specifically, the power device may be an NMOS tube, the output port of the driving circuit is connected to the gate of the NMOS tube, and the source of the NMOS tube is connected to port 3 and grounded.

[0042] In this embodiment, the first buffer includes a voltage boost circuit or a voltage drop circuit.

[0043] In a specific implementation, by setting a first buffer in the first isolation circuit, the first buffer can amplify the power of the first control signal, thereby enhancing the driving ability of the first control signal. The first buffer may also include a voltage conversion circuit (such as a boost circuit or a buck circuit). Based on the voltage conversion circuit, the first buffer can convert the voltage of the first control signal according to a specific ratio, and output the converted first control signal to the first isolation transformer T1. The primary coil of the first isolation transformer T1 receives the first control signal output by the first buffer to store energy, and converts the stored energy into an electromagnetic signal. Based on the transformer principle, the secondary coil of the first isolation transformer T1 can generate an induced current and output it to the first input end of the drive circuit.

[0044] Specifically, when the voltage of the first control signal is greater than the on-voltage of the power device, the first buffer may include a step-down circuit; when the voltage of the first control signal is less than the on-voltage of the power device, the first buffer may include a step-up circuit, thereby adjusting the voltage of the first control signal to adapt to the voltage requirement when the power device is turned on.

[0045] In this embodiment, please refer again to Figure 4 The second isolation circuit includes: a second buffer and a second isolation transformer T2; the input end of the second buffer is connected to the second output end of the control circuit, the output end of the second buffer is connected to the primary coil of the second isolation transformer T2, and the secondary coil of the second isolation transformer T2 is connected to the second input end of the drive circuit; the second buffer is used to power amplify the second control signal and output the second control signal after power amplification to the primary coil of the second isolation transformer T2.

[0046] In this embodiment, the second buffer includes a voltage boost circuit or a voltage drop circuit.

[0047] In a specific implementation, corresponding to the first buffer, the second buffer can amplify the power of the second control signal to enhance the driving capability of the second control signal. It can be understood that in order to make the second control signal adapt to the voltage requirement when the power device is turned off, the second buffer may include a voltage conversion circuit (such as a boost circuit or a buck circuit). Based on the voltage conversion circuit, the second buffer can convert the voltage of the second control signal according to a specific ratio, and output the converted second control signal to the second isolation transformer T2. The primary coil of the second isolation transformer T2 receives the second control signal output by the second buffer to store energy, and converts the stored energy into an electromagnetic signal. Based on the transformer principle, the secondary coil of the second isolation transformer T2 can generate an induced current and output it to the second input end of the drive circuit.

[0048] In this embodiment, see Figure 5 The driving circuit includes: a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a resistor R1 and a capacitor C1, the emitter of the first switch tube Q1 and the base of the first switch tube Q1 are connected to the first output end of the control circuit after being combined, the emitter of the second switch tube Q2, the base of the second switch tube Q2 and the first end of the capacitor C1 are connected to the collector of the first switch tube Q1 after being combined, and the collector of the second switch tube Q2 and the collector of the third switch tube Q3 are connected to the power device after being combined; the emitter of the fourth switch tube Q4 and the collector of the fourth switch tube Q4 are connected to the second output end of the control circuit after being combined, the collector of the fourth switch tube Q4 is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the collector of the third switch tube Q3, and the emitter of the third switch tube Q3 and the second end of the capacitor C1 are connected to ground after being combined.

[0049] In this embodiment, the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 are all NPN transistors.

[0050] Figure 5 The connection relationship between the first switch tube Q1 and the fourth switch tube Q4 in the driving circuit and the first output terminal and the second output terminal of the control circuit is not directly shown. In a specific implementation, when a first isolation circuit and a second isolation circuit are provided in the driving circuit, correspondingly, the emitter of the first switch tube Q1 and the base of the first switch tube Q1 are connected to the output terminal of the first isolation circuit after being combined, and the emitter of the fourth switch tube Q4 and the base of the fourth switch tube Q4 are connected to the output terminal of the second isolation circuit after being combined. At this time, the connection between the first isolation circuit and the second isolation circuit and the driving circuit can be specifically referred to Figure 5 The circuit structure shown.

[0051] In the driving circuit, the capacitor C1 can be used to filter the output control signal; the emitters of the first switch tube Q1, the second switch tube Q2, and the fourth switch tube Q4 are all connected to the base to act as diodes, which can be used to avoid current reversal and ensure circuit safety; when the first control signal input to port 1 is at a high level, no signal is input to port 2, and the first control signal after power amplification processing by the first isolation circuit can be output to the gate of the power device to control the driving power device to turn on; when the second control signal input to port 2 is at a high level, no signal is input to port 1, and the third switch tube Q3 is in a conducting state at this time, and the gate of the power device is grounded through the third switch tube Q3, so that the gate voltage of the power device decreases, and the power device can be controlled to be turned off, that is, the power device can be equivalent to a capacitor, when the first control signal input to port 1 is at a high level, the capacitor is charged to increase its voltage, and when the second control signal input to port 2 is at a high level, the capacitor is discharged to decrease its voltage; the resistor R1 can be used to control the time required for the gate voltage of the power device to drop to a set value, such as 0V, that is, the speed of the gate voltage drop of the power device can be adjusted by adjusting the resistance value of the resistor R1.

[0052] Embodiment 2:

[0053] This embodiment provides a power device drive control system, comprising any power device drive control circuit and a power device in the above-mentioned embodiment 1.

[0054] Compared with the prior art, the present application provides a power device drive control circuit and system, wherein the power device control circuit comprises a control circuit and a drive circuit, wherein a first output terminal of the control circuit is connected to a first input terminal of the drive circuit, a second output terminal of the control circuit is connected to a second input terminal of the drive circuit, and an output terminal of the drive circuit is connected to a power device. Since two signal transmission paths are arranged between the control circuit and the drive circuit, a first control signal for controlling the power device to turn on and a second control signal for controlling the power device to turn off are respectively transmitted to the drive circuit through different transmission paths. The drive circuit can accurately control the power device to turn on according to the first control signal, and control the power device to turn off according to the second control signal, which is beneficial to improving the reliability of the power device drive control.

[0055] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A power device drive control circuit, characterized in that: The power device driving control circuit comprises: a control circuit, a first isolation circuit, a second isolation circuit and a driving circuit; A first end of the first isolation circuit is connected to a first output end of the control circuit, and a second end of the first isolation circuit is connected to a first input end of the drive circuit; a first end of the second isolation circuit is connected to a second output end of the control circuit, and a second end of the second isolation circuit is connected to a second input end of the drive circuit, and an output end of the drive circuit is connected to a power device, and the first isolation circuit and the second isolation circuit are used to isolate the control circuit from the drive circuit; The control circuit is used to output a first control signal to the drive circuit through the first output terminal, the first control signal is used to control the power device to turn on, and is used to output a second control signal to the drive circuit through the second output terminal, the second control signal is used to control the power device to turn off, the first isolation circuit is also used to convert the voltage of the first control signal according to a set ratio, and the second isolation circuit is also used to convert the voltage of the second control signal according to a set ratio; The driving circuit is used to control the power device to turn on according to the first control signal, and to control the power device to turn off according to the second control signal; Wherein, the driving circuit includes: a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a resistor and a capacitor, the emitter of the first switch tube and the base of the first switch tube are connected to the second end of the first isolation circuit after being combined, the emitter of the second switch tube, the base of the second switch tube and the first end of the capacitor are connected to the collector of the first switch tube after being combined, and the collector of the second switch tube and the collector of the third switch tube are connected to the power device after being combined; the emitter of the fourth switch tube and the base of the fourth switch tube are connected to the second end of the second isolation circuit after being combined, the collector of the fourth switch tube is connected to the first end of the resistor, the second end of the resistor is connected to the base of the third switch tube, and the emitter of the third switch tube and the second end of the capacitor are connected to ground after being combined, wherein, when the driving circuit adjusts the gate voltage of the power device according to the second control information to control the power device to be turned off, the resistor is used to adjust the resistance value to adjust the change speed of the gate voltage of the power device.

2. The power device drive control circuit according to claim 1, characterized in that: The first isolation circuit includes: a first buffer and a first isolation transformer; The input end of the first buffer is connected to the first output end of the control circuit, the output end of the first buffer is connected to the primary coil of the first isolation transformer, and the secondary coil of the first isolation transformer is connected to the first input end of the drive circuit; The first buffer is used to perform power amplification processing on the first control signal, and output the first control signal after power amplification processing to the primary coil of the first isolation transformer.

3. The power device drive control circuit according to claim 1, characterized in that: The second isolation circuit includes: a second buffer and a second isolation transformer; The input end of the second buffer is connected to the second output end of the control circuit, the output end of the second buffer is connected to the primary coil of the second isolation transformer, and the secondary coil of the second isolation transformer is connected to the second input end of the drive circuit; The second buffer is used to perform power amplification processing on the second control signal, and output the second control signal after power amplification processing to the primary coil of the second isolation transformer.

4. The power device drive control circuit according to claim 2, characterized in that: The first buffer includes a voltage boost circuit or a voltage drop circuit.

5. The power device drive control circuit according to claim 3, characterized in that: The second buffer includes a voltage step-up circuit or a voltage step-down circuit.

6. The power device drive control circuit according to claim 1, characterized in that: The first switch tube and the second switch tube are NPN transistors.

7. The power device drive control circuit according to any one of claims 1 to 6, characterized in that: The control circuit is a pulse width modulation circuit, and the first control signal and the second control signal are pulse width modulation signals.

8. A power device drive control system, characterized in that: It comprises a power device drive control circuit and a power device as described in any one of claims 1 to 7.

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