On / off speed control circuit, power circuit and electronic device

Abstract

The invention provides a turn-on and turn-off speed control circuit, a power circuit and electronic equipment, the turn-on and turn-off speed control circuit is connected in series between a grid electrode and a drain electrode of a power device, the turn-on and turn-off speed control circuit comprises a first RCD module, a first end of a first capacitor in the first RCD module is coupled to the grid electrode or the drain electrode, and a second end of a second capacitor in the first RCD module is coupled to the grid electrode or the drain electrode; the second end of the first capacitor is coupled to the drain electrode or the grid electrode through the first diode, and the second end of the first capacitor is further coupled to the drain electrode or the grid electrode through the first resistor. Therefore, the turn-on speed or the turn-off speed of the power device is independently controlled by using the turn-on speed control circuit and the turn-off speed control circuit, the switching loss is relatively small, and the circuit efficiency is not influenced.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to an on-off speed control circuit, a power circuit and an electronic device. Background Art

[0002] In power conversion circuits, semiconductor power devices are often used as switching devices to achieve efficient control and conversion of energy. For example, in a switching power supply topology, power devices are switched on and off periodically to regulate the transmission of electrical energy. However, the switching of power devices is not instantaneous, but there is a transition phase during which the power devices are in the voltage and current overlap time, resulting in switching losses and causing the device temperature to rise.

[0003] In order to reduce switching losses, it is common to increase the switching speed of power devices. However, the increase in switching speed will cause serious electromagnetic interference (EMI) and increase the stress of related devices. This will seriously affect the operation of secondary synchronous rectification power devices in flyback power supply topologies.

[0004] Therefore, how to adjust the switching speed of power devices and reduce switching losses without affecting circuit efficiency has become a technical problem that the industry urgently needs to solve. Summary of the invention

[0005] The present invention provides a power device and an electronic device, which solves the technical problem of how to adjust the switching speed of the power device and reduce the switching loss without affecting the circuit efficiency.

[0006] According to a first aspect of the present invention, an embodiment of the present invention provides a turn-on and turn-off speed control circuit, which is applied to a power device, wherein the turn-on and turn-off speed control circuit is connected in series between a gate and a drain of the power device, and the turn-on and turn-off speed control circuit comprises a first RCD module, wherein the first RCD module comprises a first capacitor, a first resistor and a first diode; The first end of the first capacitor is coupled to the gate or the drain, the second end of the first capacitor is coupled to the drain or the gate through the first diode, and the second end of the first capacitor is also coupled to the drain or the gate through a first resistor; The power device is an NMOS tube, a PMOS tube, a silicon carbide switch tube, a depletion-type gallium nitride switch tube, an enhanced gallium nitride switch tube or a gallium oxide switch tube.

[0007] Optionally, the first RCD module further includes a second resistor; The first terminal of the first capacitor is coupled to the gate or the drain through the second resistor.

[0008] Optionally, the first RCD module further includes a third resistor; The second end of the first capacitor is coupled to the drain or the gate through the first diode and the third resistor in sequence.

[0009] Optionally, the first RCD module further includes a second capacitor; The first end of the second capacitor is coupled to the second end of the first capacitor, and the second end of the second capacitor is coupled to the drain or the gate.

[0010] Optionally, the on-off speed control circuit further includes a second RCD module, wherein the second RCD module includes a third capacitor, a fourth resistor and a second diode; The first end of the third capacitor is coupled to the gate or the drain, the second end of the third capacitor is coupled to the drain or the gate through the second diode, and the second end of the third capacitor is also coupled to the drain or the gate through a fourth resistor; Wherein, the anode of the first diode is coupled to the second end of the first capacitor, and the cathode of the first diode is coupled to the drain or the gate; An anode of the second diode is coupled to the drain or the gate, and a cathode of the second diode is coupled to the second end of the third capacitor.

[0011] Optionally, the second RCD module further includes a fifth resistor; The first terminal of the third capacitor is coupled to the gate or the drain through the fifth resistor.

[0012] Optionally, the second RCD module further includes a sixth resistor; The second end of the third capacitor is coupled to the drain or the gate through the second diode and the sixth resistor in sequence.

[0013] Optionally, the gate of the power device receives a control signal through a driving resistor.

[0014] According to a second aspect of the present invention, an embodiment of the present invention provides a power circuit, comprising a turn-on and turn-off speed control circuit as described in any one of the first aspect of the present invention.

[0015] According to a third aspect of the present invention, an embodiment of the present invention provides an electronic device, comprising a turn-on and turn-off speed control circuit as described in any one of the first aspect of the present invention.

[0016] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects: In the on-off speed control circuit, power circuit and electronic device of the technical solution of the present invention, the on-off speed control circuit is connected in series between the gate and drain of the power device, and the on-off speed control circuit includes a first RCD module, the first end of the first capacitor in the first RCD module is coupled to the gate or drain, the second end of the first capacitor is coupled to the drain or gate through the first diode, and the second end of the first capacitor is also coupled to the drain or gate through the first resistor. Therefore, the present invention uses the on-off speed control circuit to independently control the on-off speed or off-off speed of the power device, and the switching loss is small, which does not affect the circuit efficiency.

[0017] Furthermore, the turn-on and turn-off speed control circuit also includes a second RCD module, the second RCD module includes a third capacitor, a fourth resistor and a second diode; the first end of the third capacitor is coupled to the gate or the drain, the second end is coupled to the drain or the gate through the second diode, and the second end of the third capacitor is also coupled to the drain or the gate through the fourth resistor; wherein the positive electrode of the first diode is coupled to the second end of the first capacitor, the negative electrode of the first diode is coupled to the drain or the gate; the positive electrode of the second diode is coupled to the drain or the gate, and the negative electrode of the second diode is coupled to the second end of the third capacitor. Thus, the present invention uses the first RCD module and the second RCD module to control the turn-on speed and the turn-off speed of the power device respectively, and the switching loss is small, which does not affect the circuit efficiency, and also significantly improves the reliability of the power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of the opening and closing speed control circuit in the first embodiment of the prior art; Figure 2 It is a structural schematic diagram of the opening and closing speed control circuit in the second embodiment of the prior art; Figure 3 is a schematic structural diagram of an on and off speed control circuit in a first embodiment of the present invention; Figure 4 yes Figure 3 Schematic diagram of voltage waveform of the power device when it is working; Figure 5is a schematic structural diagram of an on and off speed control circuit in a second embodiment of the present invention; Figure 6 yes Figure 5 Schematic diagram of voltage waveform of the power device when it is working; Figure 7 is a schematic structural diagram of an on and off speed control circuit in a third embodiment of the present invention; Figure 8 is a schematic structural diagram of an on and off speed control circuit in a fourth embodiment of the present invention; Fig. 9 is a schematic diagram of the structure of the turn-on and turn-off speed control circuit in the fifth embodiment of the present invention and a schematic diagram of the waveform of the Vds voltage of the circuit when it is working; Fig.10 is a schematic structural diagram of an on and off speed control circuit in a sixth embodiment of the present invention; Fig.11 2 is a schematic diagram of the structure of the opening and closing speed control circuit in the seventh embodiment of the present invention.

[0020] Reference numerals: R 驱 - driving resistor; M1-power device; 10- first RCD module; 20- Second RCD module; C1-first capacitor; C2-second capacitor; C3-third capacitor; D1-first diode; D2-second diode; R1-first resistor; R2-second resistor; R3-the third resistor; R4-the fourth resistor; R5-fifth resistor; R6 - the sixth resistor. DETAILED DESCRIPTION

[0021] 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.

[0022] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0024] As described in the background art, it is difficult to adjust the switching speed of power devices and reduce switching losses without affecting circuit efficiency in the prior art.

[0025] Please refer to Figure 1 , Figure 1 It is a schematic diagram of a circuit structure for adjusting the switching speed of a power device. Figure 1 In the embodiment, by increasing the driving resistance R 驱 The switching speed of power devices can be reduced by reducing the resistance value.

[0026] Please refer to Figure 2 , Figure 2 This is another circuit diagram for adjusting the switching speed of power devices. Figure 2 In an embodiment, a switching speed of the power device is reduced by connecting a capacitor in series between the drain and source of the tube of the power device.

[0027] It is obvious that these methods increase the loss of the power device M1 and reduce the efficiency of the circuit.

[0028] In order to solve the above problems, an embodiment of the present invention provides a turn-on and turn-off speed control circuit, which is connected in series between the gate and drain of the power device, and the turn-on and turn-off speed control circuit includes a first RCD module, a first end of a first capacitor in the first RCD module is coupled to the gate or the drain, a second end of the first capacitor is coupled to the drain or the gate through a first diode, and a second end of the first capacitor is also coupled to the drain or the gate through a first resistor. Thus, the present invention uses the turn-on and turn-off speed control circuit to independently control the turn-on speed or turn-off speed of the power device, and the switching loss is small, which does not affect the circuit efficiency.

[0029] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Figure 3 The on-off speed control circuit of the embodiment of the present invention is applied to the power device M1, the on-off speed control circuit is connected in series between the gate and the drain of the power device M1, and the on-off speed control circuit includes a first RCD module 10, and the first RCD module 10 includes a first capacitor C1, a first resistor R1 and a first diode D1; A first end of the first capacitor C1 is coupled to the gate, and a second end of the first capacitor C1 is coupled to the drain through the first diode D1 . A second end of the first capacitor C1 is also coupled to the drain through a first resistor R1 .

[0031] exist Figure 3 In the example, the power device M1 is an NMOS tube. Of course, the present invention is not limited to this. The power device M1 can also be a PMOS tube, a silicon carbide (SiC) switch tube, a depletion-mode gallium nitride (GaN) switch tube, an enhanced gallium nitride switch tube or a gallium oxide switch tube.

[0032] It can be seen that the first RCD module 10 of the present invention is equivalent to increasing the Miller capacitance of the power device M1 when the power device M1 is turned on or off, so as to achieve the purpose of controlling the turn-on speed or turn-off speed of the power device M1.

[0033] exist Figure 3 In the example of , the anode of the first diode D1 is coupled to the second end of the first capacitor C1, and the cathode of the first diode D1 is coupled to the drain. In this case, the first RCD module 10 is equivalent to controlling the turn-on speed of the power device M1.

[0034] Specifically, when the power device M1 is turned on (falling edge), the first diode D1 is turned on, which is equivalent to adding a Miller capacitor between the gate and drain of the power device M1, slowing down the falling speed of Vds of the power device M1. The first resistor R1 is used to charge the first capacitor C1 to the Vds voltage when the power device M1 is turned off, so as to ensure that the power device M1 works normally when it is turned on next time.

[0035] Please continue to refer to Figure 4 , Figure 4 Shows Figure 3 The voltage waveform diagram between the drain and source of the power device M1 shown in FIG. 1 is shown in FIG. 1 when the power device M1 is turned on; wherein: ①, which can be understood as the change speed of the drain-source voltage of the power device M1 when there is no turn-on and turn-off speed control circuit connected in series between the gate and drain of the power device M1; ②, which can be understood as the change speed of the drain-source voltage of the power device M1 when the first RCD module 10 is connected in series between the gate and the drain of the power device M1.

[0036] It can be seen that the first RCD module 10 effectively slows down the drop speed of Vds, thereby reducing the turn-on speed of the power device M1.

[0037] It should be understood that the direction conversion of the overall circuit of the first RCD module 10 does not affect the effect. Figure 5 ,exist Figure 5 In the example, the first end of the first capacitor C1 is coupled to the drain, the second end of the first capacitor C1 is coupled to the gate through the first diode D1, and the second end of the first capacitor C1 is also coupled to the gate through the first resistor R1.

[0038] Furthermore, the present invention does not limit the configuration of the first diode D1. In other examples, please refer to Figure 5 , the anode of the first diode D1 can also be coupled to the drain, and the cathode of the first diode D1 can also be coupled to the second end of the first capacitor C1. In this case, the first RCD module 10 is equivalent to controlling the turn-off speed of the power device M1.

[0039] exist Figure 5 In the example, the gate of the power device M1 is driven by a resistor R 驱 Receive a control signal. Of course, the present invention is not limited thereto, and those skilled in the art can select required circuits and components to send a control signal to the gate of the power device M1.

[0040] Please continue to refer to Figure 6 , Figure 6 Shows Figure 5 The voltage waveform diagram between the drain and source of the power device M1 shown in FIG. 1 is shown in FIG. 1 when the power device M1 is turned on; wherein: ③, which can be understood as the change speed of the drain-source voltage of the power device M1 when there is no turn-on and turn-off speed control circuit connected in series between the gate and drain of the power device M1; ④, which can be understood as the change speed of the drain-source voltage of the power device M1 when the first RCD module 10 is connected in series between the gate and the drain of the power device M1.

[0041] It can be seen that the first RCD module 10 effectively slows down the rising speed of Vds, thereby reducing the turn-off speed of the power device M1.

[0042] The power device M1 with the turn-on and turn-off speed control circuit provided by the present invention can be applied in the flyback power supply topology. Taking the quasi-resonant flyback converter as an example, in the converter, since the conduction current of the switching power device M1 is theoretically close to zero when turned on, a separate turn-on speed control strategy can be adopted for the switching power device M1, so that the switch tube is turned on more slowly, and no additional turn-on loss is introduced during the turn-on process, thereby not affecting the conversion efficiency. Since the turn-on speed of the switching power device M1 is reduced in this application, the peak phenomenon of the synchronous rectifier tube caused by leakage inductance in the topology can be reduced, thereby improving the stability and reliability of the system.

[0043] It should be understood that the present invention does not limit the application scenario of the power device M1. The power device M1 provided by the present invention can be applied in any power supply topology, and those skilled in the art can also select a suitable circuit for application as needed.

[0044] Of course, the present invention can also control the turn-on speed and turn-off speed of the power device M1 simultaneously.

[0045] In one embodiment, the first RCD module 10 further includes a second capacitor C2; A first end of the second capacitor C2 is coupled to the second end of the first capacitor C1 , and a second end of the second capacitor C2 is coupled to the drain or the gate.

[0046] In a specific implementation, please refer to Figure 7 ,exist Figure 7In the example of , the anode of the first diode D1 is coupled to the second end of the first capacitor C1, and the cathode of the first diode D1 is coupled to the drain. In this case, the first diode D1 and the first capacitor C1 adjust the turn-on speed of the power device M1, and the first capacitor C1 and the second capacitor C2 also adjust the turn-off speed of the power device M1.

[0047] In another specific embodiment, please refer to Figure 8 ,exist Figure 8 In the example of , the anode of the first diode D1 is coupled to the drain, and the cathode of the first diode D1 is coupled to the second end of the first capacitor C1. In this case, the first diode D1 and the first capacitor C1 adjust the turn-off speed of the power device M1, and the first capacitor C1 and the second capacitor C2 also adjust the turn-on speed of the power device M1.

[0048] In addition, the present invention can also control the turn-on speed and turn-off speed of the power device M1 simultaneously by adding an RCD module.

[0049] In one embodiment, the on and off speed control circuit further includes a second RCD module 20, and the second RCD module 20 includes a third capacitor C3, a fourth resistor R4 and a second diode D2; A first end of the third capacitor C3 is coupled to the gate or the drain, a second end of the third capacitor C3 is coupled to the drain or the gate via the second diode D2, and a second end of the third capacitor C3 is also coupled to the drain or the gate via a fourth resistor R4; Wherein, the anode of the first diode D1 is coupled to the second end of the first capacitor C1, and the cathode of the first diode D1 is coupled to the drain or the gate; The anode of the first diode D1 is coupled to the drain or the gate, and the cathode of the first diode D1 is coupled to the second end of the third capacitor C3. Fig. 9 , a first end of the third capacitor C3 is coupled to the gate, a second end thereof is coupled to the drain through the second diode D2, and a second end of the third capacitor C3 is also coupled to the drain through a fourth resistor R4; The anode of the first diode D1 is coupled to the second end of the first capacitor C1, and the cathode of the first diode D1 is coupled to the drain; An anode of the first diode D1 is coupled to the drain, and a cathode of the first diode D1 is coupled to the second end of the third capacitor C3.

[0050] It can be seen that the present invention uses the first RCD module 10 and the second RCD module 20 to respectively control the turn-on speed and turn-off speed of the power device M1, and the switching loss is small, which does not affect the circuit efficiency, and also significantly improves the reliability of the power device M1.

[0051] Please continue to refer to Fig. 9 , Fig. 9 Also shown is a schematic diagram of the voltage waveform between the drain and the source of the power device M1 when it is turned on; wherein: ⑤, which can be understood as the change speed of the drain-source voltage Vds of the power device M1 when the first RCD module 10 and the second RCD module 20 are connected in series between the gate and the drain of the power device M1.

[0052] It can be seen that in Fig. 9 In the example, although the power device M1 adopts a PMOS tube, in this embodiment, the first RCD module 10 and the second RCD module 20 can still control the turn-on speed and the turn-off speed of the power device M1 respectively.

[0053] Now, taking the application of the power device M1 as depletion-type gallium nitride (D-GaN) as an example, other embodiments of the first RCD module 10 and / or the second RCD module 20 are described. Since depletion-type gallium nitride (D-GaN) is a cascode structure, it has almost no Miller capacitance, which makes the switching speed of the switch tube too fast, which is easy to cause reliability and EMI problems. After adopting the first RCD module 10 and the second RCD module 20 of the present invention, it is equivalent to adding a bidirectionally regulated Miller capacitance to the depletion-type gallium nitride, which can significantly improve reliability.

[0054] In actual use, the present invention can also make fine adjustments to the first RCD module 10 and / or the second RCD module 20 according to the switching speed and EMI requirements.

[0055] In a preferred embodiment, the first RCD module 10 further includes a second resistor R2; The first end of the first capacitor C1 is coupled to the gate or the drain through the second resistor R2. Fig.10 , the first end of the first capacitor C1 is coupled to the gate through the second resistor R2.

[0056] In a preferred embodiment, the second RCD module 20 further includes a fifth resistor R5; A first terminal of the third capacitor C3 is coupled to the gate or the drain through the fifth resistor R5 .

[0057] For a specific implementation, please refer to Fig.10 , the first end of the third capacitor C3 is coupled to the gate through the fifth resistor R5.

[0058] In another preferred embodiment, the first RCD module 10 further includes a third resistor R3; The second end of the first capacitor C1 is coupled to the drain or the gate through the first diode D1 and the third resistor R3 in sequence. Fig.11 , the second end of the first capacitor C1 is coupled to the drain through the first diode D1 and the third resistor R3 in sequence.

[0059] In a preferred embodiment, the second RCD module 20 may further include a sixth resistor R6; The second end of the third capacitor C3 is coupled to the drain or the gate through the second diode D2 and the sixth resistor R6 in sequence. Fig.11 ,exist Fig.11 In the example, the second end of the third capacitor C3 is coupled to the drain through the second diode D2 and the sixth resistor R6 in sequence.

[0060] visible, Fig.10 and Fig.11 The first RCD module 10 and / or the second RCD module 20 can adjust the equivalent value of the Miller capacitance of the power device M1 by connecting a resistor in series with the corresponding capacitor, thereby achieving separate control of the turn-on speed and turn-off speed of the power device M1.

[0061] It should be understood that, in actual implementation, the layout of the first RCD module 10 and / or the second RCD module 20 can be arranged in a variety of ways. Specifically, the first RCD module 10 and / or the second RCD module 20 can be placed separately outside the power device M1, or can be fully or partially integrated into the inside of the power device M1, or the first RCD module 10 and / or the second RCD module 20 can be directly embedded into the power device M1 through semiconductor technology to form an integrated structure. The present invention is not limited to this, as long as the structure of the first RCD module 10 and / or the second RCD module 20 is connected in series between the gate and the drain of the power device M1, it is within the protection scope of the present invention.

[0062] In summary, the embodiment of the present invention is designed to connect the on and off speed control circuit in series between the gate and drain of the power device, and the on and off speed control circuit includes a first RCD module, the first end of the first capacitor in the first RCD module is coupled to the gate or the drain, the second end of the first capacitor is coupled to the drain or the gate through the first diode, and the second end of the first capacitor is also coupled to the drain or the gate through the first resistor. Therefore, the present invention uses the on and off speed control circuit to independently control the on speed or off speed of the power device, and the switching loss is small, which does not affect the circuit efficiency.

[0063] In addition, the present invention further provides a power circuit, including any one of the above-mentioned turn-on and turn-off speed control circuits. As an example, the power circuit is a flyback power supply topology, etc., and the present invention is not limited to this.

[0064] In addition, the present invention also provides an electronic device, comprising any one of the above-mentioned on and off speed control circuits. As an example, the electronic device may be a power supply device, etc., and the present invention is not limited thereto.

[0065] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A turn-on and turn-off speed control circuit, characterized in that: Applied to a power device, the on-off speed control circuit is connected in series between the gate and the drain of the power device, the on-off speed control circuit comprises a first RCD module, and the first RCD module comprises a first capacitor, a first resistor and a first diode; The first end of the first capacitor is coupled to the gate or the drain, the second end of the first capacitor is coupled to the drain or the gate through the first diode, and the second end of the first capacitor is also coupled to the drain or the gate through a first resistor; The power device is an NMOS tube, a PMOS tube, a silicon carbide switch tube, a depletion-type gallium nitride switch tube, an enhanced gallium nitride switch tube or a gallium oxide switch tube.

2. The on and off speed control circuit according to claim 1, characterized in that: The first RCD module also includes a second resistor; The first terminal of the first capacitor is coupled to the gate or the drain through the second resistor.

3. The on and off speed control circuit according to claim 1, characterized in that: The first RCD module further includes a third resistor; The second end of the first capacitor is coupled to the drain or the gate through the first diode and the third resistor in sequence.

4. The on and off speed control circuit according to claim 1, characterized in that: The first RCD module also includes a second capacitor; The first end of the second capacitor is coupled to the second end of the first capacitor, and the second end of the second capacitor is coupled to the drain or the gate.

5. The on and off speed control circuit according to claim 1, characterized in that: The on and off speed control circuit further includes a second RCD module, wherein the second RCD module includes a third capacitor, a fourth resistor and a second diode; The first end of the third capacitor is coupled to the gate or the drain, the second end of the third capacitor is coupled to the drain or the gate through the second diode, and the second end of the third capacitor is also coupled to the drain or the gate through a fourth resistor; Wherein, the anode of the first diode is coupled to the second end of the first capacitor, and the cathode of the first diode is coupled to the drain or the gate; An anode of the second diode is coupled to the drain or the gate, and a cathode of the second diode is coupled to the second end of the third capacitor.

6. The on and off speed control circuit according to claim 5, characterized in that: The second RCD module further includes a fifth resistor; The first terminal of the third capacitor is coupled to the gate or the drain through the fifth resistor.

7. The on and off speed control circuit according to claim 5, characterized in that: The second RCD module further includes a sixth resistor; The second end of the third capacitor is coupled to the drain or the gate through the second diode and the sixth resistor in sequence.

8. The on and off speed control circuit according to claim 1, characterized in that: The gate of the power device receives a control signal through a driving resistor.

9. A power circuit, characterized in that: It comprises the opening and closing speed control circuit as described in any one of claims 1 to 8.

10. An electronic device, characterized in that: It comprises the opening and closing speed control circuit as described in any one of claims 1 to 8.

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