Power converter

Abstract

The application relates to a power converter, comprising a switching circuit and a control circuit; the switching circuit is connected to an electric energy transmission channel; the electric energy transmission channel is a circuit through which current flows from a power input end to a power output end when the power converter outputs electric energy; when the power converter needs to stop outputting electric energy, the electric energy transmission channel is disconnected, and the control circuit controls the switching circuit to be disconnected, so as to cut off the conduction of the parasitic diode of a synchronous MOS tube on the electric energy transmission channel, thereby realizing the simultaneous cutting off of the electric energy transmission channel and the parasitic diode of the synchronous MOS tube on the electric energy transmission channel when it is not necessary to supply power to an electric device connected to the power converter, achieving true shutdown, and avoiding the problems of electric energy waste and device damage caused by the fact that the traditional technology cannot realize true shutdown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a power converter. BACKGROUND

[0002] The power converter is an important component of the power consumption equipment, and its performance has an important influence on the power consumption equipment. The power converter in the traditional technology is composed of inductance, capacitance, control MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) tube, synchronous MOS tube and control circuit.

[0003] However, the power converter of this type has current between the power input end and the power output end due to the connection of the inductance and the parasitic diode of the synchronous MOS tube when it is turned off, so that the power converter is not substantially turned off, resulting in energy loss, and the voltage of the power output end cannot return to the initial state of 0 volts. Therefore, in the implementation process, the inventors found that the traditional boost power converter cannot realize true turn-off. SUMMARY

[0004] Therefore, it is necessary to provide a power converter to solve the problem that the traditional boost power converter cannot realize true turn-off.

[0005] In order to achieve the above-mentioned purpose, the embodiments of the present application provide a power converter, which comprises a switching circuit and a control circuit.

[0006] The switching circuit is connected to an electric energy transmission channel. The electric energy transmission channel is a circuit through which the current of the power converter flows from the power input end to the power output end when the power converter outputs electric energy.

[0007] When the power converter needs to stop outputting electric energy, the electric energy transmission channel is disconnected, and the control circuit controls the switching circuit to be disconnected, so as to cut off the conduction of the parasitic diode of the synchronous MOS tube on the electric energy transmission channel.

[0008] Optionally, the switching circuit comprises a switching MOS tube.

[0009] The source and the substrate of the switching MOS tube are connected to the substrate of the synchronous MOS tube, the drain is connected to the drain of the synchronous MOS tube, and the gate is connected to the control circuit.

[0010] The parasitic diode of the synchronous MOS tube is parasitic between the source of the synchronous MOS tube and the source of the switching MOS tube.

[0011] Optionally, the switching MOS tube is a P-type MOS tube.

[0012] The control circuit inputs a high level signal to the switch MOS tube to control the switch MOS tube to be turned off.

[0013] Optionally, the switch MOS tube is an N-type MOS tube.

[0014] The control circuit inputs a low level signal to the switch MOS tube to control the switch MOS tube to be turned off.

[0015] Optionally, the switch circuit comprises a switch triode.

[0016] The emitter of the switch triode is connected to the substrate of the synchronous MOS tube, the collector is connected to the drain of the synchronous MOS tube, and the base is connected to the control circuit.

[0017] The parasitic diode of the synchronous MOS tube is parasitic between the source of the synchronous MOS tube and the emitter of the switch triode.

[0018] Optionally, the switch triode is a P-type triode.

[0019] The control circuit inputs a high level signal to the switch triode to control the switch triode to be turned off.

[0020] Optionally, the switch triode is an N-type triode.

[0021] The control circuit inputs a low level signal to the switch triode to control the switch triode to be turned off.

[0022] Optionally, the power converter further comprises a PWM control driver.

[0023] The PWM control driver is connected to the gate of the synchronous MOS tube, and the control circuit is integrated on the PWM control driver.

[0024] Optionally, the power converter further comprises an inductor, a control MOS tube, and a capacitor.

[0025] The PWM control driver is further connected to the gate of the control MOS tube.

[0026] One end of the inductor is connected to the source of the synchronous MOS tube and the drain of the control MOS tube respectively, and the other end is used as a power input end; the source and the substrate of the control MOS tube are grounded.

[0027] The drain of the synchronous MOS tube is used as a power output end and grounded through the capacitor.

[0028] Optionally, the power converter further comprises a PWM control driver, an inductor, a control MOS tube, and a capacitor.

[0029] The PWM control driver is connected to the gate of the synchronous MOS tube and the gate of the control MOS tube respectively.

[0030] One end of the inductor is connected to the source of the synchronous MOS transistor and the drain of the control MOS transistor respectively, and the other end is used as the power input terminal; the source of the control MOS transistor and the substrate are grounded.

[0031] The drain of the synchronous MOS transistor is used as the power output terminal and is grounded through a capacitor.

[0032] The above technical solution has the following advantages and beneficial effects:

[0033] The power converter of the present application comprises a switching circuit and a control circuit, wherein the switching circuit is arranged on an electric energy transmission channel (the electric energy transmission channel refers to a circuit between the power input terminal and the power output terminal of the power converter), when the power converter needs to stop outputting electric energy, the power converter disconnects the electric energy transmission channel, and the control circuit controls the switching circuit to disconnect, so as to cut off the conduction of the parasitic diode of the synchronous MOS transistor on the electric energy transmission channel, thereby realizing that when the power converter does not need to supply power to the connected electrical devices, the electric energy transmission channel and the parasitic diode of the synchronous MOS transistor on the electric energy transmission channel are simultaneously cut off, true shutdown is achieved, and the problems of electric energy waste and damage to devices caused by the inability to achieve true shutdown in the conventional technology are avoided. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a circuit diagram of a boost power converter in the conventional technology.

[0035] Figure 2 It is Figure 1 It is a switching point waveform diagram of the circuit diagram shown in the figure.

[0036] Figure 3 It is a structural schematic diagram of the power converter provided by the present application.

[0037] Figure 4 It is a circuit diagram of the switching circuit of the power converter provided by the present application.

[0038] Figure 5 It is another circuit diagram of the switching circuit of the power converter provided by the present application.

[0039] Figure 6 It is a structural schematic diagram of the control circuit of the power converter provided by the present application.

[0040] Figure 7 It is a control timing diagram of the power converter provided by the present application.

[0041] Figure 8 It is a current flow direction diagram of the power converter provided by the present application.

[0042] Figure 9A structural diagram of the power converter provided for implementation of this application in the off state.

[0043] Explanation of icon numbers:

[0044] 3. Power converter; 31. Switching circuit; 32. Control circuit; 33. Power transmission channel; 34. Synchronous MOSFET; 35. PWM control driver; 36. Inductor; 37. Control MOSFET; 38. Capacitor; 311. Switching MOSFET; 313. Switching transistor. Detailed Implementation

[0045] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0046] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to and integrated with the other component, or there may be an intervening component present. The terms "mounted," "one end," "the other end," and similar expressions used in this document are for illustrative purposes only.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0048] like Figure 1 The diagram shows a conventional boost converter, comprising an inductor 11, a capacitor 12, a control MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) 13, a parasitic diode 14 of the control MOSFET 13, a synchronous MOSFET 15, a parasitic diode 16 of the synchronous MOSFET 15, and a control circuit 17. The control circuit 17 includes PWM (Pulse Width Modulation) and BBW (Boost-Boost-Warp) converters.

[0049] See Figure 2 It showed Figure 1 The switching point (V) of the boost converter shown x Waveform, from Figure 2 From time t=0 to time t=t1, control MOSFET 13 is turned on, switching point (Vx ) is low impedance ground, the voltage is determined by the product of the current flowing through the control MOS 13 and its on impedance. When the control MOS 13 is off, and the synchronous MOS 15 has not yet turned on, because the inductor 11 current follows the KCL (Kirchhoff's current law) law, the parasitic diode 16 of the synchronous MOS 15 is turned on, thus, the voltage at the end of the inductor 11 is equal to V out + V out + V f (as shown in paragraph 32 of Figure 2 ), wherein V f is the on voltage of the parasitic diode 16 of the synchronous MOS 15. Thereafter, when the synchronous MOS 15 is turned on, the voltage is as shown in paragraph 33 of Figure 2 . When the synchronous MOS 15 is turned off again, the voltage is as shown in paragraph 34 of Figure 2 . When the energy stored in the inductor 11 is consumed, the voltage drops rapidly, and the voltage is as shown in Figure 2 at t = t1. According to the above steps, in the boost operation case, each component acts according to the instructions of the control circuit 17 to achieve the purpose of boosting. Figure 1

[0050] However, in the off case of the boost power converter, because the inductor 11 is connected with the parasitic diode 16 of the synchronous MOS 15, the current inevitably flows from V batt to V out , thereby causing the boost power converter not to be substantially turned off, resulting in energy loss of V batt . In the off case of the boost power converter, the voltage V out cannot return to the initial state of 0 volts, so that the boost power converter cannot achieve true off. Figure 1

[0051] In order to solve the above problems, as shown in Figure 3 , a power converter 3 is provided, which comprises a switching circuit 31 and a control circuit 32.

[0052] In actual use, the power output end of the power converter 3 is connected with the electrical device, and the power input end of the power converter 3 is connected with the voltage source or the current source. When the power converter 3 supplies power to the electrical device through the power output end (i.e. outputs power), the current flows from the power input end to the power output end, and the circuit through which the current flows from the power input end (such as V batt shown in Figure 3 ) to the power output end (such as V out shown in Figure 3 ) is the power transmission channel of the power converter 3.

[0053] ​​The switch circuit 31 is connected to the power transmission channel, and is used to cut off the conduction of the parasitic diode of the synchronous MOS tube 34 in the power transmission channel. The parasitic diode of the synchronous MOS tube 34 is caused by the production process, and is formed by leading out the MOS tube drain from the bottom of the silicon wafer. The synchronous MOS tube 34 is used as a switching component, and is controlled by a level signal to realize the disconnection or conduction of the power transmission channel. For example, when the synchronous MOS tube 34 is a P-type MOS tube, the synchronous MOS tube 34 is disconnected when the level signal is a high level signal, and the synchronous MOS tube 34 is connected when the level signal is a low level signal. When the synchronous MOS tube 34 is an N-type MOS tube, the synchronous MOS tube 34 is disconnected when the level signal is a low level signal, and the synchronous MOS tube 34 is connected when the level signal is a high level signal. Specifically, the level signal is input to the gate of the synchronous MOS tube 34. In order to control the synchronous MOS tube 34, as shown in Figure 3 In one example, the power converter 3 further includes a PWM control driver 35 connected to the gate of the synchronous MOS tube 34. It can be understood that the PWM control driver 35 inputs the level signal to the synchronous MOS tube 34.

[0054] In the process of outputting power, the power transmission channel is connected, and the control circuit 32 controls the switch circuit 31 to be connected, so as to connect the parasitic diode of the synchronous MOS tube 34 in the power transmission channel. When the power converter 3 needs to stop outputting power (i.e., the power supply to the electrical device is not needed), the power transmission channel is disconnected, and the control circuit 32 controls the switch circuit 31 to be disconnected, so as to cut off the conduction of the parasitic diode of the synchronous MOS tube 34 in the power transmission channel. It should be noted that the connection of the parasitic diode of the synchronous MOS tube 34 in the power transmission channel means that the parasitic diode of the synchronous MOS tube 34 is connected to the power transmission channel. The cutting off of the conduction of the parasitic diode of the synchronous MOS tube 34 in the power transmission channel means that the parasitic diode of the synchronous MOS tube 34 is disconnected from the power transmission channel.

[0055] The implementation mode of the switch circuit 31 is not limited, and the switch circuit 31 can realize the functions required by the present application. Two feasible modes are provided as follows:

[0056] As shown in Figure 4 In one example, the switch circuit 31 includes a switch MOS tube 311, the source and substrate of the switch MOS tube 311 are connected to the substrate of the synchronous MOS tube 34, the drain of the switch MOS tube 311 is connected to the drain of the synchronous MOS tube 34, and the gate of the switch MOS tube 311 is connected to the control circuit 32. The parasitic diode of the synchronous MOS tube 34 is parasitic between the source of the synchronous MOS tube 34 and the source of the switch MOS tube 311.

[0057] It should be noted that when the switching MOSFET 311 is a P-type MOSFET, the control circuit 32 inputs a high-level signal to the switching MOSFET 311 to control it to turn off, and inputs a low-level signal to the switching MOSFET 311 to control it to turn on. When the switching MOSFET 311 is an N-type MOSFET, the control circuit 32 inputs a low-level signal to the switching MOSFET 311 to control it to turn off, and inputs a high-level signal to the switching MOSFET 311 to control it to turn on.

[0058] like Figure 5 As shown, in another example, the switching circuit 31 includes a switching transistor 313; the emitter of the switching transistor 313 is connected to the substrate of the synchronous MOS transistor 34, the collector is connected to the drain of the synchronous MOS transistor 34, and the base is connected to the control circuit 32; the parasitic diode of the synchronous MOS transistor 34 is parasitic between the source of the synchronous MOS transistor 34 and the emitter of the switching transistor 313.

[0059] It should be noted that when the switching transistor 313 is a P-type transistor, the control circuit 32 inputs a high-level signal to the switching transistor 313 to control it to turn off, and inputs a low-level signal to the switching transistor 313 to control it to turn on. When the switching transistor 313 is an N-type transistor, the control circuit 32 inputs a low-level signal to the switching transistor 313 to control it to turn off, and inputs a high-level signal to the switching transistor 313 to control it to turn on.

[0060] The control circuit 32 sends control signals to the switching circuit 31 to control the opening and closing of the switching circuit 31. For example, the control circuit 32 can be a microcontroller, a signal generator, etc. In one example, the control circuit 32 can detect whether the electrical device connected to the power converter 3 needs power. When it detects that the electrical device needs power (i.e., it needs the power converter 3 to output power), the control circuit 32 controls the switching circuit 31 to turn on. When it detects that the electrical device does not need power (i.e., it needs the power converter 3 to output power), the control circuit 32 controls the switching circuit 31 to turn off. In another example, an external detection circuit can detect whether the electrical device connected to the power converter 3 needs power. When the external detection circuit detects that the electrical device needs power, it notifies the control circuit 32 so that the control circuit 32 controls the switching circuit 31 to turn on. When the external detection circuit detects that the electrical device does not need power, it notifies the control circuit 32 so that the control circuit 32 controls the switching circuit 31 to turn off. For example, the external detection circuit can be a PWM control driver 35.

[0061] In one example, such as Figure 6 As shown, the control circuit 32 and the PWM control driver 35 are the same device, meaning the control circuit 32 is integrated onto the PWM control driver 35. Specifically, the power converter 3 also includes a PWM control driver 35; the PWM control driver 35 is connected to the gate of the synchronous MOSFET 34; and the control circuit 32 is integrated onto the PWM control driver 35. It should be noted that integrating the control circuit 32 onto the PWM control driver 35 saves on component usage and reduces costs. In this example, when power conversion is required to output electrical energy, the PWM control driver 35 controls the synchronous MOSFET 34 to conduct, thereby activating the power transmission channel of the power converter 3. The control circuit 32 controls the switching circuit 31 to conduct, thereby activating the parasitic diode of the synchronous MOSFET 34, thus enabling the power converter 3 to supply power to the connected electrical devices. When power conversion output is not required, the PWM control driver 35 controls the synchronous MOSFET 34 to disconnect to cut off the power transmission channel of the power converter 3, and the control circuit 32 controls the switching circuit 31 to cut off the conduction of the parasitic diode of the synchronous MOSFET 34, thereby enabling the power converter 3 to stop supplying power to the connected electrical devices.

[0062] In this example, the power converter 3 also includes an inductor 36, a control MOSFET 37, and a capacitor 38; the PWM control driver 35 is also connected to the gate of the control MOSFET 37; one end of the inductor 36 is connected to the source of the synchronous MOSFET 34 and the drain of the control MOSFET 37 respectively, and the other end serves as the power input terminal; the source and substrate of the control MOSFET 37 are grounded; the drain of the synchronous MOSFET 34 serves as the power output terminal and is grounded through the capacitor 38.

[0063] It should be noted that inductor 36 is used to connect to a voltage source or current source as an energy storage device. During the charging process of inductor 36, PWM control driver 35 controls control MOSFET 37 to conduct, controls synchronous MOSFET 34 to conduct, and control circuit 32 controls switching circuit 31 to conduct, in order to charge inductor 36. When power converter 3 needs to output power, PWM control driver 35 controls control MOSFET 37 to conduct, controls synchronous MOSFET 34 to conduct, and control circuit 32 controls switching circuit 31 to conduct, in order to output power. When power converter 3 does not need to output power, PWM control driver 35 controls control MOSFET 37 to conduct, controls synchronous MOSFET 34 to conduct, and control circuit 32 controls switching circuit 31 to conduct, in order to stop outputting power.

[0064] In another example, such as Figure 3As shown, the control circuit 32 and the PWM control driver 35 are independent devices. Specifically, the power converter 3 also includes a PWM control driver 35, an inductor 36, a control MOSFET 37, and a capacitor 38; the PWM control driver 35 is connected to the gate of the synchronous MOSFET 34 and the gate of the control MOSFET 37 respectively; one end of the inductor 36 is connected to the source of the synchronous MOSFET 34 and the drain of the control MOSFET 37 respectively, and the other end serves as the power input terminal; the source and substrate of the control MOSFET 37 are grounded; the drain of the synchronous MOSFET 34 serves as the power output terminal and is grounded through the capacitor 38.

[0065] It should be noted that the control circuit 32 and the PWM control driver 35 are two separate devices; they can be connected or disconnected. When the control circuit 32 and the PWM control driver 35 are connected, the PWM control driver 35 can detect whether the electrical equipment needs power and notify the control circuit 32 accordingly. When the control circuit 32 and the PWM control driver 35 are not connected, the control circuit 32 needs to detect whether the electrical equipment needs power independently, or an external detection circuit can be used for detection.

[0066] To better understand the working principle of the power converter 3 of this application, a specific embodiment is described below:

[0067] like Figure 4 As shown, the power converter 3 includes a switching circuit 31, a control circuit 32, a PWM control driver 35, an inductor 36, a synchronous MOSFET 34, a control MOSFET 37, and a capacitor 38. The synchronous MOSFET 34 is a P-type MOSFET. The control MOSFET 37 is an N-type MOSFET.

[0068] The switching circuit 31 includes a switching MOSFET 311, and the control circuit 32 is connected to the gate of the switching MOSFET 311. The switching MOSFET 311 is a P-type MOSFET.

[0069] The PWM control driver 35 is connected to the gate of the synchronous MOSFET 34 and the gate of the control MOSFET 37, respectively.

[0070] One end of inductor 36 is connected to the source of synchronous MOSFET 34 and the drain of control MOSFET 37, respectively, and the other end serves as the power input terminal, while the source of control MOSFET 37 and the substrate are grounded.

[0071] The drain of synchronous MOSFET 34 serves as the power output terminal and is grounded through capacitor 38.

[0072] The parasitic diode of synchronous MOSFET 34 is located between the source of synchronous MOSFET 34 and the source of switching MOSFET 311.

[0073] The inductor 36 and the synchronous MOSFET 34 between the power input terminal and the power output terminal constitute the power transmission channel of the power converter 3.

[0074] According to Figure 7 The timing diagram shown controls the power converter 3 in this example. Figure 7 This includes the drive signal for synchronous MOSFET 34, the drive signal for control MOSFET 37, and the enable signal for switching MOSFET 311. During normal charging and discharging of the power converter 3, synchronous MOSFET 34 and control MOSFET 37 are controlled by two identical drive signals. At this time, the enable signal for switching MOSFET 311 is a low-level signal. Specifically, during charging, the drive signals for synchronous MOSFET 34 and control MOSFET 37 are high-level signals, synchronous MOSFET 34 is off, and control MOSFET 37 is on. During discharging, the drive signals for synchronous MOSFET 34 and control MOSFET 37 are low-level signals, synchronous MOSFET 34 is on, and control MOSFET 37 is off. When it is necessary to turn off the power converter 3, the drive signal for synchronous MOSFET 34 is high-level, the drive signal for control MOSFET 37 is low-level, and the enable signal for switching MOSFET 311 is high-level, thus disconnecting synchronous MOSFET 34, control MOSFET 37, and switching MOSFET 311, and the power converter 3 stops outputting power to the connected electrical devices.

[0075] like Figure 8 The diagram shows the current flow of power converter 3 in this example. During normal charging and discharging of power converter 3, switching MOSFET 311 is turned on, synchronous MOSFET 34 switches between on and off according to its corresponding drive signal, and control MOSFET 37 also switches between on and off according to its corresponding drive signal. Therefore, there are three current paths in power converter 3 during this process. Specifically, the first current path: the current flows sequentially through the power input terminal, inductor 36, the parasitic diode of synchronous MOSFET 34, switching MOSFET 311, and power output terminal; the second current path: when the drive signal is high voltage, synchronous MOSFET 34 is off, control MOSFET 37 is turned on, and the current flows sequentially through the power input terminal, inductor 36, and control MOSFET 37; the third current path: when the drive signal is low voltage, synchronous MOSFET 34 is turned on, control MOSFET 37 is off, and the current flows sequentially through the power input terminal, inductor 36, synchronous MOSFET 34, and power output terminal. The power converter 3 of this application provides the first current path, while... Figure 1 The conventional boost converter 3 shown does not have this current path.

[0076] like Figure 9The shown is the off mode of the power converter 3 in the example. In the off mode, the drive signal of the synchronous MOS tube 34 is a high level signal, the drive signal of the control MOS tube 37 is a low level signal, and the enable signal of the switch MOS tube 311 is a high level signal, so as to realize the disconnection of the synchronous MOS tube 34, the control MOS tube 37 and the switch MOS tube 311. After the off, the three current paths in the power converter 3 do not exist, and the true off is realized.

[0077] The power converter 3 of the application comprises a switch circuit 31 and a control circuit 32, wherein the switch circuit 31 is arranged on the electric energy transmission channel (the electric energy transmission channel refers to the circuit between the power input end and the power output end of the power converter 3), when the power converter 3 needs to stop outputting electric energy, the power converter 3 disconnects the electric energy transmission channel, and the control circuit 32 controls the switch circuit 31 to disconnect, so as to cut off the conduction of the parasitic diode of the synchronous MOS tube 34 on the electric energy transmission channel, thereby realizing that when the power converter 3 does not need to supply power to the connected electrical devices, the electric energy transmission channel and the parasitic diode of the synchronous MOS tube 34 on the electric energy transmission channel are cut off at the same time, the true off is realized, and the problems of electric energy waste and damage to devices caused by the fact that the traditional technology cannot realize the true off are avoided. Moreover, the power converter 3 of the application only uses one MOS tube to solve the problems in the traditional technology, and the cost is low. At the same time, since the switch MOS tube 311 is in the conduction state during the charging and discharging process of the power converter 3, the circuit can be shared, and then the problems such as Figure 2 The switching point (V x ) wave type 32 segments of the voltage is too high to cause damage to the control MOS tube 37.

[0078] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the description.

[0079] The above-mentioned embodiments only express several implementation manners of the application, the description is more specific and detailed, but it should not be understood as the limitation of the patent application scope. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which all belong to the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A power converter, characterized by, A power output of a power converter is connected with an electrical device, a power input of the power converter is connected with a voltage source or a current source, and the power converter comprises a switching circuit and a control circuit; The switching circuit is connected on an electric energy transmission channel; the electric energy transmission channel is a circuit through which a current of the power converter flows from the power input to the power output when the power converter outputs electric energy; The control circuit can detect whether the electrical device needs to use electricity, or an external detection circuit detects whether the electrical device needs to use electricity; when it is detected that the electrical device needs to use electricity, the control circuit controls the switching circuit to be turned on; When it is detected that the electrical device does not need to use electricity, the control circuit controls the switching circuit to be turned off; When the power converter needs to stop outputting electric energy, the electric energy transmission channel is disconnected, and the control circuit controls the switching circuit to be turned off to cut off the conduction of a parasitic diode of a synchronous MOS tube on the electric energy transmission channel; The switching circuit comprises a switching MOS tube or a switching triode; The source and the substrate of the switching MOS tube are connected with the substrate of the synchronous MOS tube, the drain is connected with the drain of the synchronous MOS tube, and the gate is connected with the control circuit; The parasitic diode of the synchronous MOS tube is parasitic between the source of the synchronous MOS tube and the source of the switching MOS tube; The emitter of the switching triode is connected with the substrate of the synchronous MOS tube, the collector is connected with the drain of the synchronous MOS tube, and the base is connected with the control circuit; The parasitic diode of the synchronous MOS tube is parasitic between the source of the synchronous MOS tube and the emitter of the switching triode.

2. The power converter of claim 1, wherein, The switching MOS tube is a P-type MOS tube; The control circuit inputs a high-level signal to the switching MOS tube to control the switching MOS tube to be turned off.

3. The power converter of claim 1, wherein, The switching MOS tube is an N-type MOS tube; The control circuit inputs a low-level signal to the switching MOS tube to control the switching MOS tube to be turned off.

4. The power converter of claim 1, wherein, The switching triode is a P-type triode; The control circuit inputs a high-level signal to the switching triode to control the switching triode to be turned off.

5. The power converter of claim 1, wherein, The switching triode is an N-type triode; The control circuit inputs a low-level signal to the switching triode to control the switching triode to be turned off.

6. The power converter according to any one of claims 1 to 5, characterized by The power converter further comprises a PWM control driver; The PWM control driver is connected with the gate of the synchronous MOS tube; and the control circuit is integrated on the PWM control driver.

7. The power converter of claim 6, wherein, The power converter further comprises an inductor, a control MOS tube, and a capacitor; The PWM control driver is further connected with the gate of the control MOS tube; One end of the inductor is connected with the source of the synchronous MOS tube and the drain of the control MOS tube respectively, and the other end is used as the power input; the source and the substrate of the control MOS tube are grounded; The drain of the synchronous MOS tube is used as the power output and is grounded through the capacitor.

8. The power converter according to any one of claims 1 to 5, characterized by The power converter further comprises a PWM control driver, an inductor, a control MOS tube, and a capacitor; The PWM control driver is connected to the gate of the synchronous MOS tube and the gate of the control MOS tube respectively; One end of the inductor is connected to the source of the synchronous MOS tube and the drain of the control MOS tube respectively, and the other end is used as the power input end; the source of the control MOS tube and the substrate are grounded; The drain of the synchronous MOS tube is used as the power output end and grounded through the capacitor.

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