Voltage converter

Abstract

The application provides a voltage converter. The voltage converter comprises a primary circuit, a secondary circuit and a discharge control unit. The secondary circuit comprises a first MOS tube and an output capacitor. The first MOS tube is connected with the discharge control unit. The discharge control unit is used for controlling the first MOS tube to work in a linear region when the voltage converter is in a shutdown state or an abnormal protection state. In the technical scheme, after the voltage converter stops working, the first MOS tube is controlled to work in the linear region, so that the first MOS tube consumes the residual voltage on the output capacitor in the voltage converter as a resistance. In this way, when the voltage converter is started, the pre-bias voltage is reduced or disappears, so that an excessively large reverse current is avoided, and thus the failure of components in the voltage converter is avoided.

Description

Technical Field

[0001] This application relates to the field of circuits, and more particularly to voltage converters. Background Technology

[0002] Active clamp forward (ACF) converters offer numerous advantages, including high efficiency, low output ripple, and low cost, making them widely used in low-to-medium power DC-DC converters. In low-voltage, high-current output scenarios, the secondary-side rectifier freewheeling diode is often replaced by a synchronous rectifier field-effect transistor (MOSFET / MOS). Typically, during the output pre-biased power-on phase of an ACF converter, excessive energy can accumulate on the secondary-side output capacitor, causing this energy to flow back to the primary side. This results in significant voltage and current stress on both the primary and secondary MOSFETs, potentially leading to component failure due to excessive stress.

[0003] Therefore, how to prevent the ACF converter from failing due to excessive derating of device voltage and current stress caused by energy backflow on the output capacitor during power-on has become an urgent technical problem to be solved. Summary of the Invention

[0004] This application provides a voltage converter that can prevent the ACF converter from failing due to excessive voltage and current stress caused by energy backflow on the output capacitor during power-on.

[0005] In a first aspect, this application provides a voltage converter, which includes a primary-side circuit, a secondary-side circuit, and a discharge control unit. The secondary-side circuit includes a first field-effect transistor (MOSFET) and an output capacitor. The first MOSFET is connected to the discharge control unit. The first MOSFET is used to: operate in the linear region and release the energy of the output capacitor when the voltage converter is in a shutdown state or an abnormal protection state. The abnormal protection state includes a state where the supply voltage of the voltage converter is greater than a first threshold or a state where the operating temperature is higher than a second threshold. The output capacitor is used to: filter the output voltage of the voltage converter. The discharge control unit is used to: control the first MOSFET to operate in the linear region when the voltage converter is in a shutdown state or an abnormal protection state.

[0006] In this aspect, when the voltage converter is in the off state or in an abnormal protection state, the freewheeling MOSFET is controlled to operate in the linear region, so that the freewheeling MOSFET acts as a resistor to dissipate the residual voltage in the output capacitor of the voltage converter. In this way, when the voltage converter is turned on, the pre-bias voltage will decrease or disappear, thereby avoiding the generation of excessive reverse current and thus preventing the failure of components in the voltage converter.

[0007] In conjunction with the first aspect, in one possible implementation, the discharge control unit includes a first driving unit for the first MOS transistor and a power supply unit for the first driving unit. The first driving unit is connected to the first MOS transistor, and the power supply unit is connected to the first driving unit. The power supply unit is used to output a first power supply signal to the first driving unit when the voltage converter is in a closed state or an abnormal protection state. The first driving unit is used to drive the first MOS transistor to operate in the linear region when it receives the first power supply signal.

[0008] This implementation describes the structure of the discharge control unit, in which the power supply unit supplies power to the first drive unit to change the state of the first MOS transistor so that it can operate in the linear region.

[0009] In conjunction with the first aspect, in one possible implementation, the first driving unit includes a second MOS transistor, the source of which is connected to the gate of the first MOS transistor, the gate of which is connected to a power supply unit, and the drain of which is connected to the first secondary winding of a transformer in a voltage converter.

[0010] This implementation describes the components included in the first driving unit and their connection relationships. The first driving unit can be a MOSFET to receive power supply signals to control the operating state of the first MOSFET.

[0011] In conjunction with the first aspect, in one possible implementation, the power supply unit includes a first energy storage subunit, a first terminal of which is connected to the first drive unit, and a second terminal of which is grounded; the first energy storage subunit is used to output a first power supply signal to the first drive unit when the voltage converter is in a closed state or an abnormal protection state.

[0012] This implementation describes the composition and connection relationship of the power supply unit. The power supply unit may include a first energy storage subunit to store electrical energy when the voltage converter is turned on and to supply power to the first drive unit when the voltage converter is in a turned-off state or an abnormal protection state.

[0013] In conjunction with the first aspect, in one possible implementation, the first energy storage sub-unit includes a capacitor.

[0014] This implementation describes the components included in the first energy storage sub-unit. The first energy storage sub-unit may be a capacitor to store electrical energy when the voltage converter is turned on and to release electrical energy when it is turned off or under abnormal protection.

[0015] In conjunction with the first aspect, in one possible implementation, the first energy storage subunit is further configured to: output a second power supply signal to the first driving unit when the voltage converter is in the ON state, the second power supply signal being used to control the first driving unit to output a first signal to the first MOSFET to control the first MOSFET to turn on; correspondingly, the power supply unit further includes a second energy storage subunit, a discharge control subunit, and a resistor unit, the first terminal of the second energy storage subunit being connected to the first terminal of the resistor unit, the second terminal of the resistor unit being connected to the first terminal of the first energy storage subunit, the second terminal of the second energy storage subunit being grounded, and the first terminal of the first energy storage subunit being connected to the discharge control subunit; the discharge control subunit is configured to: control the first energy storage subunit to release the electrical energy stored when the voltage converter is in the ON state when the voltage converter is in the OFF state or in an abnormal protection state; the second energy storage subunit is configured to: charge the first energy storage subunit through the resistor unit after the first energy storage subunit releases the stored electrical energy; when the first energy storage subunit outputs the first power supply signal to the first driving unit, it is specifically configured to: output the first power supply signal to the first driving unit during the process of the second energy storage subunit charging the first energy storage subunit.

[0016] This implementation further defines the function of the first energy storage sub-unit and the composition of the power supply unit, which includes a second energy storage sub-unit, a discharge control sub-unit, and a resistor unit. The first energy storage sub-unit can also control the first MOSFET to turn on when the voltage converter is turned on, so that the first MOSFET turns off when the voltage converter is turned off or under abnormal protection. After the first energy storage sub-unit has discharged its charge, the second energy storage sub-unit charges it, a slow process that allows the first MOSFET to be in a partially conducting state, i.e., operating in the linear region.

[0017] In conjunction with the first aspect, in one possible implementation, the second energy storage sub-unit includes a capacitor.

[0018] This implementation describes the components included in the second energy storage subunit, which can be a capacitor to store electrical energy when the voltage converter is turned on and release electrical energy when it is turned off or under abnormal protection.

[0019] In conjunction with the first aspect, in one possible implementation, the power supply unit further includes a Zener diode connected in parallel with the first energy storage subunit.

[0020] In this implementation, the composition of the power supply unit is further defined. The power supply unit also includes a Zener diode to stabilize the voltage across the first energy storage sub-unit.

[0021] In conjunction with the first aspect, in one possible implementation, the discharge control subunit includes a control subunit and a discharge unit. The first terminal of the discharge unit is connected to the first terminal of the first energy storage subunit, and the second terminal of the discharge unit is grounded. The control subunit is configured to: output a first control signal to the discharge unit when the voltage converter is in a closed state or an abnormal protection state; the first control signal is used to control the discharge unit to conduct. The discharge unit is configured to: connect the first terminal of the first energy storage subunit to ground under the control of the first control signal. The control subunit is further configured to: output a second control signal to the discharge unit after inputting the first control signal for a first duration; the second control signal is used to control the discharge unit to turn off. The discharge unit is further configured to: disconnect the connection between the first terminal of the first energy storage subunit and ground under the control of the second control signal.

[0022] This implementation describes the configuration of the discharge control subunit, in which the control subunit outputs a control signal to control the discharge unit to turn on or off, so as to release the electrical energy in the first energy storage subunit, so that the first energy storage subunit can be charged by the second energy storage subunit, so that the first MOS transistor can operate in the linear region.

[0023] In conjunction with the first aspect, in one possible implementation, the electron discharge unit includes a photosensitive unit, and the control subunit includes a first port, a second port, a third energy storage subunit, and a light-emitting unit; wherein the first port of the control subunit, the light-emitting unit, the third energy storage subunit, and the second port of the control subunit are connected in series; the first port of the control subunit is used to receive a first electrical signal when the voltage converter is in a closed state or an abnormal protection state; the second port of the control subunit is used to receive a second electrical signal when the voltage converter is in a closed state or an abnormal protection state, wherein the voltage of the first electrical signal is higher than that of the second electrical signal. The voltage; the third energy storage subunit is used to: charge during the process of receiving a first electrical signal at the first port of the control subunit and receiving a second electrical signal at the second port of the control subunit; the light-emitting unit is used to: output a light signal to the photosensitive unit before the third energy storage subunit is fully charged; the photosensitive unit is used to: connect the first terminal of the first energy storage subunit to the ground after receiving the light signal; the light-emitting unit is also used to: stop outputting a light signal to the photosensitive unit after the third energy storage subunit is fully charged; the photosensitive unit is also used to: disconnect the connection between the first terminal of the first energy storage subunit and the ground after the light-emitting unit stops outputting a light signal.

[0024] This implementation describes the components included in the control subunit and its control process. By releasing the electrical energy of the first energy storage subunit, the second energy storage subunit can charge the first energy storage subunit, thereby supplying power to the first drive unit, so that the first MOS transistor can operate in the linear region.

[0025] In conjunction with the first aspect, in one possible implementation, the second port is connected to a first pin of the primary-side control unit of the voltage converter, the state of which indicates the operating state of the primary-side control unit.

[0026] In this implementation, the connection pins between the control subunit and the control unit of the voltage converter are described. The working state of the primary control unit can be known through the state of the connection pins. That is, when the voltage converter is turned off or under abnormal protection, the third energy storage subunit in the control subunit is further triggered to charge and the discharge unit is turned on to release the electrical energy in the first energy storage subunit.

[0027] In conjunction with the first aspect, in one possible implementation, the photosensitive unit includes a phototransistor, the light-emitting unit includes a light-emitting diode, the positive terminal of the light-emitting diode is connected to the first port of the control subunit, and the negative terminal of the light-emitting diode is connected to the third energy storage subunit.

[0028] In this implementation, the photosensitive unit and the light-emitting unit are further defined. For example, the photosensitive unit can be a phototransistor, and the light-emitting unit can be a light-emitting diode. The phototransistor will conduct when it receives a light signal to release the electrical energy of the first energy storage subunit.

[0029] In conjunction with the first aspect, in one possible implementation, the third energy storage sub-unit includes a capacitor.

[0030] This implementation describes the components included in the third energy storage sub-unit. The third energy storage sub-unit can be a capacitor, which is charged when the voltage converter is turned off or under abnormal protection to turn on the light-emitting unit.

[0031] In conjunction with the first aspect, in one possible implementation, the voltage converter further includes a transformer, and the power supply unit further includes a conduction control subunit. One end of the conduction control subunit is connected to the second secondary winding of the transformer, and the other end of the conduction control subunit is connected to the first end of the resistor unit. The conduction control subunit is used to: conduct the second secondary winding of the transformer and the first end of the resistor unit when the voltage converter is in the on state, and to turn off the second secondary winding of the transformer and the first end of the resistor unit when the voltage converter is in the off state or in an abnormal protection state.

[0032] In this implementation, the composition of the voltage converter and the power supply unit is further defined. The power supply unit also includes a turn-on control subunit to charge the first energy storage subunit and the second energy storage subunit when the voltage converter is turned on.

[0033] In conjunction with the first aspect, in one possible implementation, the conduction control subunit includes a diode, the positive terminal of which is connected to the second secondary winding, and the negative terminal of which is connected to the first end of the resistor unit.

[0034] This implementation describes the components included in the conduction control subunit. For example, the conduction control subunit can be a diode, which has unidirectional conductivity. When the voltage converter is in the on state, it conducts the second secondary winding of the transformer and the first end of the resistor unit, which can charge the first and second energy storage subunits. When the voltage converter is in the off state or in an abnormal protection state, it disconnects the second secondary winding of the transformer and the first end of the resistor unit, so that the electrical energy of the first and second energy storage subunits does not flow out from it.

[0035] Secondly, this application provides an electronic device, the electronic device comprising: a voltage converter as described in the first aspect or any possible implementation thereof, the voltage converter being used to provide voltage conversion functionality for the electronic device.

[0036] In conjunction with the second aspect, in one possible implementation, the electronic device includes any one of the following: a router, a switch, a server, and a wireless base station. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the basic structure of the ACF topology provided in the embodiments of this application;

[0038] Figure 2 A structural diagram of the ACF topology provided in another embodiment of this application;

[0039] Figure 3 A structural diagram of the ACF topology provided in yet another embodiment of this application;

[0040] Figure 4 This is a schematic diagram of the structure of a voltage converter provided in one embodiment of this application;

[0041] Figure 5 This is a schematic diagram of the structure of a voltage converter provided in another embodiment of this application;

[0042] Figure 6 This is a schematic diagram of the structure of a voltage converter provided in yet another embodiment of this application;

[0043] Figure 7 This is a schematic diagram of the structure of a voltage converter provided in yet another embodiment of this application;

[0044] Figure 8 This is a schematic diagram of the structure of a voltage converter provided in yet another embodiment of this application;

[0045] Figure 9 This is a schematic diagram of the structure of a voltage converter provided in yet another embodiment of this application;

[0046] Figure 10This is an exemplary structural diagram of a voltage converter provided in one embodiment of this application;

[0047] Figure 11 This is a schematic diagram of the actual operating waveform of a voltage converter provided in one embodiment of this application;

[0048] Figure 12 This is a schematic diagram of the structure of an electronic device provided in one embodiment of this application. Detailed Implementation

[0049] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0050] With the development of chip integration technology, communication and computer products are becoming smaller and more intelligent, leading to increasingly higher requirements for DC / DC power supply systems. Currently, independently isolated load transformers designed on the load side are collectively referred to as isolated DC / DC converters. As a common modular power supply in industry, they have been widely used in the power supply systems of communication, network, and computer equipment.

[0051] A common topology in isolated DC / DC converters is the ACF topology, which offers advantages such as high efficiency, low output ripple, and low cost. In low-voltage, high-current output scenarios, the secondary-side rectifier freewheeling diode is replaced by a synchronous rectifier MOSFET. Specifically... Figure 1 As shown.

[0052] Figure 1 This is a schematic diagram of the basic structure of an ACF topology provided in one embodiment of this application. Figure 1 As shown, the primary circuit of the ACF topology includes clamping capacitor C1, main power transistor Q1 and clamping power transistor Q2. Transformer T1 includes primary winding, secondary winding 1 and secondary winding 2. The secondary circuit of the ACF topology includes output capacitor C5, filter inductor Lo, rectifier power transistor Q3, driver circuit 1 for rectifier power transistor Q3, freewheeling power transistor Q4 and driver circuit 2 for freewheeling power transistor Q4.

[0053] In this circuit, the opposite-named terminal of the primary winding of transformer T1, the first terminal of clamping capacitor C1, and the drain of main power transistor Q1 are connected; the second terminal of clamping capacitor C1 is connected to the drain of clamping power transistor Q2; the source of main power transistor Q1 and the source of clamping power transistor Q2 are connected; the same-named terminal of secondary winding 1 of transformer T1, the first terminal of filter inductor Lo, and the drain of freewheeling power transistor Q4 are connected; and the opposite-named terminal of secondary winding 1, the drain of rectifier power transistor Q3, and the first terminal of drive circuit 2 for freewheeling power transistor Q4 are connected. The second terminal of the drive circuit 2 for the freewheeling power transistor Q4 is connected to the gate of the freewheeling power transistor Q4. The second terminal of the filter inductor Lo is connected to the first terminal of the output capacitor C5. The second terminal of the output capacitor C5, the source of the rectifier power transistor Q3, the source of the freewheeling power transistor Q4, and the opposite-named terminal of the secondary winding 2 of the transformer T1 are connected. The same-named terminal of the secondary winding 2 is connected to the first terminal of the drive circuit 1 for the rectifier power transistor Q3. The second terminal of the drive circuit 1 for the rectifier power transistor Q3 is connected to the gate of the rectifier power transistor Q3.

[0054] Optionally, the driving circuit 1 and the driving circuit 2 may include transistors, diodes, and resistors, etc. This application does not limit the specific composition of the driving circuit 1 and the driving circuit 2.

[0055] Specifically, such as Figure 1 As shown, during the soft-start phase, when the drive duty cycle of the primary-side main power transistor Q1 gradually increases from 0%, due to the self-driving characteristics of the winding, the drive duty cycle of the rectifier power transistor Q3 gradually increases from 0%, while the drive duty cycle of the freewheeling power transistor Q4 gradually decreases from 100%. Because the freewheeling power transistor Q4 has a long turn-on time, the filter inductor Lo, under the influence of the pre-bias voltage, will generate a large reverse current. This reverse current will also be transmitted to the primary side through the transformer when the rectifier power transistor Q3 is turned on, resonating with the primary-side clamping capacitor C1. This generates a very high voltage across the clamping capacitor C1, and the higher the output voltage, the more severe the reverse current phenomenon and the greater the stress on the devices.

[0056] In other words, when a voltage converter with the above-mentioned ACF topology is powered on with output pre-bias, there will be a situation where energy flows back from the output end to the input end during the soft-start phase. This backflow of energy from the output end will bring great voltage and current stress to the MOSFETs in the primary and secondary circuits, which may lead to excessive stress and failure of the devices.

[0057] It should be noted that, Figure 1 The ACF topology shown is merely an example, and this application does not limit the specific structure of the ACF topology. The ACF topology can also be called a switching power supply.

[0058] In current related technologies, in order to avoid the failure of ACF converter due to excessive voltage and current stress derating when the device is repeatedly and rapidly switched on and off, those skilled in the art have proposed adding a dead load or an independent secondary controller at the power output terminal. The specific implementation method is described in detail below with reference to the accompanying drawings.

[0059] Optionally, Figure 2 A structural diagram of the ACF topology provided for another embodiment of this application. (See diagram below.) Figure 2 As shown, this topology is in Figure 1 Based on the ACF topology shown, a load Rload is connected in parallel across the output capacitor C5.

[0060] In other words, Figure 1 Based on the circuit structure, the second end of the filter inductor Lo, the first end of the output capacitor C5, and the first end of the load Rload are connected. The second end of the load Rload, the second end of the capacitor C5, the source of the rectifier power transistor Q3, the source of the freewheeling power transistor Q4, and the opposite-named terminal of the secondary winding 2 of the transformer T1 are grounded.

[0061] Specifically, when the switching power supply is turned off, the electrical energy on the output capacitor C5 can continue to be consumed by the load Rload, reducing the voltage on the output capacitor C5 when the power is turned on again, reducing reverse flow, and reducing the voltage and current stress on the MOS.

[0062] However, this method of adding a load to the power supply output requires a small-value resistor to quickly reduce the voltage across the output capacitor, which significantly reduces the power supply's efficiency. Therefore, a larger resistance value is generally used. However, a larger resistance load has a slower discharge speed and cannot handle rapid power-on / off scenarios.

[0063] Optionally, Figure 3 This is a structural diagram of an ACF topology provided in yet another embodiment of this application. (See diagram below.) Figure 3 As shown, the primary-side circuit of this topology is as follows: Figure 1 The primary circuit shown in the ACF topology will not be described in detail here; the secondary circuit includes rectifier power transistor Q3, freewheeling power transistor Q4, filter inductor Lo and output capacitor C5, and transformer T1 includes primary winding and secondary winding.

[0064] In this circuit, the opposite-named terminal of the secondary winding of transformer T1 is connected to the drain of rectifier power transistor Q3. The source of rectifier power transistor Q3, the drain of freewheeling power transistor Q4, and the first terminal of output capacitor C5 are connected and grounded. The second terminal of output capacitor C5 is connected to the first terminal of filter inductor Lo. The second terminal of filter inductor Lo, the source of freewheeling power transistor Q4, and the same-named terminal of the secondary winding are connected.

[0065] This topology employs an independent secondary controller to control the operating states of the rectifier power transistor Q3 and the freewheeling power transistor Q4. Specifically, during the power switch's soft-start phase, the secondary controller keeps both rectifier power transistor Q3 and freewheeling power transistor Q4 in diode mode. Since diodes have unidirectional conductivity, the voltage across the output capacitor C5 is cut off by rectifier power transistor Q3 and freewheeling power transistor Q4, preventing current from flowing back into the primary circuit. Simultaneously, because the efficiency of rectifier power transistor Q3 and freewheeling power transistor Q4 is low when operating in diode mode, after the power switch's soft-start is complete, rectifier power transistor Q3 and freewheeling power transistor Q4 need to be turned on to operate in synchronous rectification mode.

[0066] It should be noted that the rectifier and freewheeling power transistors in the embodiments of this application are all synchronous rectifier MOSFETs.

[0067] However, this solution also requires a separate controller on the secondary side to drive the secondary rectifier power transistor Q3 and the freewheeling power transistor Q4. Furthermore, the change in circuit gain caused by the switching of the operating modes of rectifier power transistor Q3 and freewheeling power transistor Q4 can cause output voltage overshoot, which needs to be resolved by slowly switching the operating modes of rectifier power transistor Q3 and freewheeling power transistor Q4. This makes the solution complex and costly to implement.

[0068] Therefore, how to effectively avoid the high pre-bias voltage at the output terminal of the ACF voltage converter during repeated rapid power-on and power-off, which would cause energy backflow at the output terminal during power-on and lead to excessive voltage and current stress on the device and failure, has become an urgent technical problem to be solved.

[0069] In view of this, this application proposes a voltage converter, such as Figure 4 As shown, the voltage converter includes a secondary circuit 401, a discharge control unit 402, and a primary circuit 404. The secondary circuit 401 includes a first MOSFET 4011 and an output capacitor 4012. The first MOSFET 4011 is connected to the discharge control unit 402.

[0070] The first MOSFET 4011 is used to operate in the linear region when the voltage converter is in the off state or in an abnormal protection state, releasing the energy of the output capacitor 4012. The abnormal protection state includes the state when the supply voltage of the voltage converter is greater than a first threshold or the state when the operating temperature is higher than a second threshold. The output capacitor 4012 is used to filter the output voltage of the voltage converter. The discharge control unit 402 is used to control the first MOSFET 4011 to operate in the linear region when the voltage converter is in the off state or in an abnormal protection state.

[0071] Specifically, the first MOSFET 4011 operating in the linear region means that the first MOSFET 4011 is in a partially turned-on state. At this time, the first MOSFET 4011 is equivalent to a variable resistor, which can consume the electrical energy of the output capacitor 4012.

[0072] It should be noted that when the voltage converter is in the off state or in the abnormal protection state, the first MOSFET 4011 is driven to operate in the linear region, which may happen instantaneously, that is, at the instant the voltage converter is turned off or at the instant the abnormal protection occurs.

[0073] Optionally, the abnormal protection state of the voltage converter includes excessively high supply voltage or excessively high operating temperature. The abnormal protection state also includes the voltage converter failing to work properly due to device failure or some uncontrollable factors. This application does not limit the reasons for the voltage converter entering abnormal protection.

[0074] When the voltage converter is working normally, the output capacitor 4012 will charge and store electrical energy. When the voltage converter is turned off or under abnormal protection, the discharge control unit 402 will control the first MOSFET 4011 to work in the linear region, so that the first MOSFET 4011 acts as a resistor to consume the electrical energy of the output capacitor 4012. In this way, when the voltage converter is turned on again, a large bias voltage will not be generated across the output capacitor 4012, which could lead to component failure.

[0075] In other words, in this embodiment, when the voltage converter is in a shutdown state or an abnormal protection state, the freewheeling MOSFET is controlled to operate in the linear region, thereby causing the freewheeling MOSFET to act as a resistor to dissipate the residual voltage in the output capacitor of the voltage converter. Thus, when the voltage converter is powered on, the pre-bias voltage will decrease or disappear, thereby avoiding excessive reverse current and preventing component failure in the voltage converter.

[0076] Optionally, the output capacitor 4012, also known as the output filter capacitor, is used to filter the output voltage, making the output voltage more stable.

[0077] It should be noted that the primary circuit of the voltage converter is connected to a DC power supply to provide the input voltage. When the DC power supply is on, if the pulse width modulation (PWM) controller in the primary circuit outputs a waveform, the voltage converter is in normal operation; if the PWM controller in the primary circuit does not output a waveform, the voltage converter is in standby mode; when the DC power supply is not on, the voltage converter is in a power-off state; the voltage converter being in a shutdown state includes being in standby mode or power-off mode; the voltage converter being in an abnormal protection state is equivalent to the voltage converter being in standby mode.

[0078] Optionally, in the embodiments of this application, the voltage converter being powered on or in an on state refers to the voltage converter entering a normal working state, the voltage converter being powered off or in a closed state refers to the voltage converter being in a standby state or a power-off state, and the voltage converter being in an abnormal protection state refers to the voltage converter being in a standby state.

[0079] Optionally, such as Figure 5 As shown, the discharge control unit 402 includes a first driving unit 4021 of the first MOS transistor 4011 and a power supply unit 4022 of the first driving unit 4021. The first driving unit 4021 is connected to the first MOS transistor 4011, and the power supply unit 4022 is connected to the first driving unit 4021.

[0080] The power supply unit 4022 is mainly used to output a first power supply signal to the first drive unit 4021 when the voltage converter is in the off state or abnormal protection state; when the first drive unit 4021 receives the first power supply signal, it drives the first MOS transistor 4011 to work in the linear region.

[0081] In other words, the power supply unit 4022 is used to supply power to the first drive unit 4021, and the first drive unit 4021 controls the working state of the first MOS transistor 4011.

[0082] In this embodiment, the power supply unit in the discharge control unit is used to supply power to the first drive unit to change the state of the first MOS transistor so that it can operate in the linear region.

[0083] Optionally, such as Figure 6 As shown, the first driving unit 4021 includes a second MOS transistor 40211. The source S of the second MOS transistor 40211 is connected to the gate G of the first MOS transistor 4011. The gate G of the second MOS transistor 40211 is connected to the power supply unit 4022. The drain D of the second MOS transistor 40211 is connected to the first secondary winding 403 of the transformer in the voltage converter.

[0084] It should be noted that the voltage converter also includes a transformer, which includes a first secondary winding 403.

[0085] In this embodiment, the first driving unit can be a MOSFET. The characteristics of the MOSFET are used to process the applied voltage to obtain a stable voltage, which is then used to control the working state of the first MOSFET 4011, thus protecting the components to a certain extent.

[0086] Optionally, such as Figure 7 As shown, the power supply unit 4022 includes a first energy storage subunit 40221. The first end of the first energy storage subunit 40221 is connected to the first drive unit 4021, and the second end of the first energy storage subunit 40221 is grounded.

[0087] When the voltage converter is in a closed state or an abnormal protection state, the first energy storage sub-unit 40221 outputs a first power supply signal to the first drive unit 4021.

[0088] Specifically, the power supply unit 4022 in the discharge control unit 402 is used to supply power to the first drive unit 4021. The power supply unit 4022 includes a first energy storage subunit 40221. The first energy storage subunit 40221 stores electrical energy when the voltage converter is powered on, and supplies power to the first drive unit 4021 when the voltage converter is powered off or in an abnormal protection state.

[0089] Optionally, the first energy storage subunit 40221 may include a capacitor that can be charged and discharged.

[0090] Optionally, the first energy storage subunit 40221 is also used to output a second power supply signal to the first drive unit 4021 when the voltage converter is in the on state, so as to control the first drive unit 4021 to output a first signal to the first MOSFET 4011 and control the first MOSFET 4011 to turn on.

[0091] In other words, when the voltage converter is working normally, there is a stable voltage across the first energy storage sub-unit, which can supply power to the first drive unit 4021 to control the first MOS transistor 4011 to turn on.

[0092] Accordingly, such as Figure 8 As shown, the power supply unit 4022 also includes a second energy storage subunit 40222, a discharge control subunit 40223, and a resistor unit 40224. The first end of the second energy storage subunit 40222 is connected to the first end of the resistor unit 40224, the second end of the resistor unit 40224 is connected to the first end of the first energy storage subunit 40221, the second end of the second energy storage subunit 40222 is grounded, and the first end of the first energy storage subunit 40221 is connected to the discharge control subunit 40223.

[0093] Specifically, the discharge control subunit 40223 is used to control the first energy storage subunit 40221 to release the electrical energy stored when the voltage converter is in the off state or abnormal protection state; the second energy storage subunit 40222 is used to charge the first energy storage subunit 40221 through the resistor unit 40224 after the first energy storage subunit 40221 releases the stored electrical energy; when the first energy storage subunit 40221 outputs the first power supply signal to the first drive unit 4021, it is specifically used to output the first power supply signal to the first drive unit 4021 during the process of the second energy storage subunit 40222 charging the first energy storage subunit 40221.

[0094] In other words, when the discharge control subunit 40223 receives a signal that the voltage converter is off or abnormally protected, it releases the electrical energy in the first energy storage subunit 40221; after the first energy storage subunit 40221 is depleted, the second energy storage subunit 40222 charges the first energy storage subunit 40221 to supply power to the first drive unit 4021.

[0095] In this embodiment, the second energy storage sub-unit charges the first energy storage sub-unit after the first energy storage sub-unit has been depleted. This is a slow process, which allows the first MOS transistor to be in a partially conducting state, i.e., operating in the linear region.

[0096] Optionally, the second energy storage subunit 40222 may include a capacitor that can be charged and discharged.

[0097] Optionally, the power supply unit 4022 also includes a Zener diode connected in parallel across the first energy storage subunit 40221 to stabilize the voltage of the first energy storage subunit.

[0098] Optionally, such as Figure 9 As shown, the discharge control subunit 40223 includes a control subunit 402231 and a discharge unit 402232. The first terminal of the discharge unit 402232 is connected to the first terminal of the first energy storage subunit 40221, and the second terminal of the discharge unit is grounded. The control subunit 402231 is used to output a first control signal to the discharge unit 402232 when the voltage converter is in a closed state or an abnormal protection state, so as to control the discharge unit 402232 to conduct. The discharge unit 402232 is used to connect the first terminal of the first energy storage subunit 40221 to the ground under the control of the first control signal.

[0099] In other words, when the voltage converter is in a closed state or an abnormal protection state, the control subunit turns on the discharge unit, which releases the electrical energy in the first energy storage subunit.

[0100] Furthermore, the control subunit 402231 is also used to input a first control signal to the discharge unit 402232 for a first duration, and then output a second control signal to the discharge unit 402232. The second control signal is used to control the discharge unit 402232 to turn off. The discharge unit 402232 is also used to disconnect the connection between the first end of the first energy storage subunit 40221 and the ground under the control of the second control signal.

[0101] In other words, after the first duration, the control subunit 402231 shuts off the discharge unit 402232, at which point the electrical energy in the first energy storage subunit 40221 is basically released.

[0102] In this embodiment, the control subunit outputs a control signal to control the discharge unit to turn on or off, so as to release all the electrical energy in the first energy storage subunit, so that the first energy storage subunit can be charged by the second energy storage subunit, so that the first MOS transistor can work in the linear region.

[0103] Optionally, the electron discharge unit 402232 includes a photosensitive unit, and the control subunit 402231 includes a first port, a second port, a third energy storage subunit, and a light-emitting unit.

[0104] The control subunit 402231's first port, light-emitting unit, third energy storage subunit, and control subunit's second port are connected in series. The first port of control subunit 402231 receives a first electrical signal when the voltage converter is in a closed or abnormal protection state. The second port of control subunit 402231 receives a second electrical signal when the voltage converter is in a closed or abnormal protection state, wherein the voltage of the first electrical signal is higher than the voltage of the second electrical signal. The third energy storage subunit is charged while the control subunit 402231 receives the first electrical signal at its first port and the second electrical signal at its second port. The light-emitting unit outputs a light signal to the photosensitive unit before the third energy storage subunit is fully charged. The photosensitive unit connects the first terminal of the first energy storage subunit 40221 to ground after receiving the light signal. The light-emitting unit also stops outputting a light signal to the photosensitive unit after the third energy storage subunit is fully charged, causing the photosensitive unit to disconnect the connection between the first terminal of the first energy storage subunit 40221 and ground.

[0105] In other words, when the voltage converter is off or under abnormal protection, the voltage level at the first port of the control subunit 402231 is higher than that at the second port, which charges the third energy storage subunit. This causes the light-emitting unit to emit light, the photosensitive unit to conduct, and the electrical energy in the first energy storage subunit 40221 to be released. When the third energy storage subunit is fully charged, the light-emitting unit stops emitting light, and the photosensitive unit disconnects. The trigger condition for this process is that the voltage converter is off or under abnormal protection, causing a change in the voltage level at the second port.

[0106] Optionally, the first port is connected to a regulated power source, i.e., a high level, and the second port becomes a low level when the voltage converter is turned off or under abnormal protection.

[0107] In this embodiment, the components included in the control subunit and its control process are described. By releasing the electrical energy of the first energy storage subunit, the second energy storage subunit can charge the first energy storage subunit, thereby supplying power to the first drive unit, so that the first MOS transistor can operate in the linear region.

[0108] Optionally, the second port of the control subunit 402231 is connected to the first pin of the primary-side control unit of the voltage converter, and the state of the first pin indicates the operating state of the primary-side control unit.

[0109] For example, the first pin of the primary-side control unit can be the "Fault" pin of the pulse width modulation (PWM) controller. This pin indicates whether the controller has fault protection, such as over-temperature protection. When the controller temperature exceeds 135 degrees, the chip stops working, and this pin changes from high level to low level to indicate that the chip is under over-temperature protection.

[0110] The operating status of the primary control unit can be determined based on the status of the first pin, such as whether it is on, off, or in an abnormal protection state.

[0111] For example, when the voltage converter is turned off or under abnormal protection, the first pin of the primary control unit becomes low, that is, the second port of the control subunit 402231 is low. Then the level of the first port is higher than the level of the second port, the third energy storage subunit is charged, and the discharge unit is turned on to release the electrical energy in the first energy storage subunit.

[0112] Optionally, the photosensitive unit includes a phototransistor, and the light-emitting unit includes a light-emitting diode (LED). The positive terminal of the LED is connected to the first port of the control subunit, and the negative terminal of the LED is connected to the third energy storage subunit. For example, when the LED is turned on, it emits a light signal, causing the phototransistor to turn on.

[0113] Optionally, the third energy storage subunit includes a capacitor that can be charged and discharged.

[0114] Optionally, the voltage converter also includes a transformer, and the power supply unit 4022 also includes a conduction control subunit. One end of the conduction control subunit is connected to the second secondary winding of the transformer, and the other end of the conduction control subunit is connected to the first end of the resistor unit 40224.

[0115] The conduction control subunit is used to conduct the second secondary winding of the transformer and the first terminal of the resistor unit 40224 when the voltage converter is in the on state, and to turn off the second secondary winding of the transformer and the first terminal of the resistor unit 40224 when the voltage converter is in the off state or in an abnormal protection state.

[0116] In other words, when the voltage converter is in the on state, the transformer charges the first energy storage subunit 40221 and the second energy storage subunit 40222 through the conduction control subunit.

[0117] Optionally, the conduction control subunit includes a diode, the positive terminal of which is connected to the second secondary winding, and the negative terminal of which is connected to the first terminal of the resistor unit 40224.

[0118] Because diodes have unidirectional conductivity, when the voltage converter is in the on state, the second secondary winding of the transformer is connected to the first end of the resistor unit, which can charge the first energy storage sub-unit and the second energy storage sub-unit; when the voltage converter is in the off state or in an abnormal protection state, the second secondary winding of the transformer is disconnected from the first end of the resistor unit, so that the electrical energy of the first energy storage unit and the second energy storage unit does not flow out from it.

[0119] As an example, Figure 10 This is an exemplary structural diagram of a voltage converter provided in one embodiment of this application. In conjunction with the above embodiments, as shown... Figure 10 As shown, the voltage converter includes: a primary circuit, a secondary circuit, a discharge control unit, and a transformer T1.

[0120] The secondary circuit includes: a first MOSFET Q4 (the aforementioned first MOSFET 4011), an output capacitor C5 (the aforementioned output capacitor 4012), a filter inductor Lo, a MOSFET Q3, and a driving unit Q5 for the MOSFET Q3.

[0121] The discharge control unit includes: a driving unit Q6 for the first MOSFET Q4 (the aforementioned first driving unit 4021), a capacitor C3 (the aforementioned first energy storage sub-unit 40221), a capacitor C4 (the aforementioned second energy storage sub-unit 40222), a resistor R2 (the aforementioned resistor unit 40224), a Zener diode D2 (the aforementioned Zener diode in the aforementioned power supply unit 4022), a diode D1 (the aforementioned conduction control sub-unit), an optocoupler assembly U1 (a phototransistor and a light-emitting diode), a capacitor C2 (the aforementioned third energy storage sub-unit), and a resistor R1.

[0122] Transformer T1 includes: a first secondary winding (the aforementioned first secondary winding 403) and a second secondary winding.

[0123] The primary circuit includes: capacitor C1, MOSFET Q1, MOSFET Q2, control unit PWM, supply voltage (voice-controlled carrier, VCC), and power supply S.

[0124] Optionally, the gate of Q4 is connected to the source of Q6; the drain of Q4, the same-name terminal of Lo, and the same-name terminal of the first secondary winding are connected; the source of Q4, the first terminal of C5, the source of Q3, and the second terminal of C3 are connected and grounded; the drain of Q6, the drain of Q3, and the opposite-name terminal of the first secondary winding are connected; the opposite-name terminal of Lo is connected to the second terminal of C5; the gate of Q6, the gate of Q5, and the first terminal of C3 are connected; the second terminal of R2, the first terminal of C3, and the negative terminal of the Zener diode are connected, and the positive terminal of the Zener diode is connected to the second terminal of C3; the first terminal of C4 is connected to the first terminal of R2, and the second terminal of C4 is grounded; the first terminal of C3 is connected to the first terminal of the phototransistor in U1; and the phototransistor... The second terminal is grounded. The gate of Q3 is connected to the source of Q5. The drain of Q5 is connected to the second secondary winding. The positive terminal of D1 is connected to the second secondary winding. The negative terminal of D1 is connected to the first terminal of R2. The LEDs in VCC, R1, and U1 are connected in series with C2. The positive terminal of the LED is connected to the first terminal of R1. The negative terminal of the LED is connected to the first terminal of C2. The second terminal of C2 is connected to the first pin of PWM. The opposite terminal of the primary winding, the first terminal of C1, and the drain of Q1 are connected. The second terminal of C1 is connected to the drain of Q2. The source of Q1 is connected to the source of Q2. The gates of Q1 and Q2 are connected to PWM. S is connected to the same terminal of the primary winding and the source of Q1.

[0125] As an example, when the voltage converter is operating normally, the second secondary winding generates a stable voltage through D1, R2, C3, and D2, which powers Q5 and Q6, and in doing so, charges C3 and C4.

[0126] When the voltage converter is turned off or under abnormal protection, the first pin of the PWM changes from high level to low level. The low level signal is connected to the second terminal of C2. C2 is charged through the LED in VCC, R1, and U1. Before C2 is fully charged, it outputs a light signal to the phototransistor in U1. After the phototransistor receives the light signal, it turns on, and C3 discharges through the phototransistor. At this time, the power supply to Q5 and Q6 is cut off, causing Q3 and Q4 to turn off.

[0127] Furthermore, once C2 is fully charged, it stops outputting optical signals to the phototransistor, and the phototransistor no longer conducts. The residual voltage on C4 charges C3 through R2. At this time, the drain voltage of Q6 is equal to the bias voltage on C5. Therefore, the source voltage of Q6 (the gate voltage of Q4) increases as the voltage across C3 increases. When the gate voltage of Q4 rises to the turn-on threshold voltage, Q4 operates in the linear region, that is, Q4 is in a partially conducting state. The bias voltage of C5 discharges through Lo and Q4.

[0128] Optionally, when C5 is discharging, the drain voltage of Q decreases. When the voltage of C5 drops below the threshold voltage of the gate of Q4, Q4 operates in the cutoff region, that is, Q4 is not turned on.

[0129] Optionally, selecting a suitable Q4 can lower the bias voltage of C5. The selection of R2 and C3 is related to the charging speed of C3. Specifically, it is necessary to consider that the charging speed of C3 should not be too fast, otherwise the minimum on-resistance (Rdson) of Q4 will be too low, thus the discharge current will exceed the derating of the MOSFET. It is also necessary to consider that the charging voltage of C3 should not be too low, so that the maximum gate-source (Vgs) of Q4 will not reach the turn-on threshold. The selection of Q4 needs to consider the safe operating area and transient temperature rise to ensure that the MOSFET will not be damaged by the discharge current.

[0130] This application's embodiments can be used in low-cost, small-size ACF topology power supply scenarios. Specifically, when the voltage converter is in a shutdown or abnormal protection state, the freewheeling MOSFET is controlled to operate in the linear region, thereby causing the freewheeling MOSFET to act as a resistor to dissipate the residual voltage in the output capacitor of the voltage converter. In this way, when the voltage converter is powered on, the pre-bias voltage will decrease or disappear, thereby avoiding excessive reverse current and preventing component failure in the voltage converter.

[0131] As another example, the actual operating waveform of the voltage converter provided in this application embodiment is as follows: Figure 11 As shown, after the ACF voltage converter is turned off, Q4 is turned on again, and the voltage of C5 discharges from 5V to 1.88V. There will be no stress problem caused by reverse flow when the power is turned on again.

[0132] Specifically, when the voltage converter is working normally (not powered off), C3 is in a charging state with a high voltage. At the moment the voltage converter is powered off or undergoes abnormal protection (at time point t1 in the figure), the voltage of C3 drops suddenly, and C4 charges C3 through R2, causing the voltage across C3 to gradually rise. When the voltage converter is working normally (not powered off), the voltage driving Q6 of Q4 is in the range of V2 to V1. At the moment the voltage converter is powered off or undergoes abnormal protection, the voltage driving Q6 of Q4 goes low, and as the voltage of C3 increases, the voltage of Q6 gradually increases. When the voltage of C5 is not powered off, it has a high voltage. As the voltage of Q6 rises, Q4 turns on (at time point b in the figure), and the voltage across C5 gradually decreases to a certain value (at time point a in the figure) and then remains basically unchanged.

[0133] Correspondingly, the discharge current on C5 increases as Q4 is turned on, and the current gradually decreases when the voltage on C5 drops to a certain value.

[0134] The embodiments of this application can cleverly utilize the freewheeling MOSFET of the ACF voltage converter to discharge the output capacitor after power-off, thereby avoiding various device stress damage problems caused by pre-biased power-on.

[0135] Furthermore, the structural schematic diagram of the electronic device provided in the embodiments of this application is as follows: Figure 12 As shown, the electronic device includes: the voltage converter described in the above embodiments, which is used to provide voltage conversion functionality for the electronic device.

[0136] The electronic device can be a network device such as a router, switch, server, or wireless base station.

[0137] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0138] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0139] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0140] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0141] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0142] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0143] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0144] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0145] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0146] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A voltage converter, characterized by The voltage transformer comprises a primary side circuit, a secondary side circuit and a discharge control unit, the secondary side circuit comprises a first MOS tube and an output capacitor, and the first MOS tube is connected with the discharge control unit; The first MOS tube is configured to work in a linear region to release electric energy of the output capacitor when the voltage transformer is in a closed state or an abnormal protection state, and the abnormal protection state comprises a state where a supply voltage of the voltage transformer is greater than a first threshold value or a state where a working temperature is higher than a second threshold value; The output capacitor is configured to filter an output voltage of the voltage transformer; The discharge control unit is configured to control the first MOS tube to work in the linear region when the voltage transformer is in the closed state or the abnormal protection state; The discharge control unit comprises a first driving unit of the first MOS tube and a supply unit of the first driving unit, the first driving unit is connected with the first MOS tube, and the supply unit is connected with the first driving unit; The supply unit comprises a first energy storage subunit, a first end of the first energy storage subunit is connected with the first driving unit, and a second end of the first energy storage subunit is grounded; The first energy storage subunit is further configured to output a second supply signal to the first driving unit when the voltage transformer is in an open state, the second supply signal is used to control the first driving unit to output a first signal to the first MOS tube, and the first signal is used to control the first MOS tube to be turned on; The supply unit further comprises a second energy storage subunit, a discharge control subunit and a resistance unit, a first end of the second energy storage subunit is connected with a first end of the resistance unit, a second end of the resistance unit is connected with a first end of the first energy storage subunit, a second end of the second energy storage subunit is grounded, and the first end of the first energy storage subunit is connected with the discharge control subunit; The supply unit is configured to output a first supply signal to the first driving unit when the voltage transformer is in the closed state or the abnormal protection state; The discharge control subunit is configured to control the first energy storage subunit to release electric energy stored when the voltage transformer is in the open state when the voltage transformer is in the closed state or the abnormal protection state; The second energy storage subunit is configured to charge the first energy storage subunit through the resistance unit after the first energy storage subunit releases the stored electric energy; When the first energy storage subunit outputs the first supply signal to the first driving unit, the first energy storage subunit is specifically configured to output the first supply signal to the first driving unit in a process of charging the first energy storage subunit by the second energy storage subunit.

2. The voltage transformer of claim 1, wherein The first driving unit is configured to drive the first MOS tube to work in the linear region when the first supply signal is received.

3. Voltage converter according to claim 2, characterized in that The first driving unit comprises a second MOS tube, a source of the second MOS tube is connected with a gate of the first MOS tube, a gate of the second MOS tube is connected with the power supply unit, and a drain of the second MOS tube is connected with a first secondary winding of a transformer in the voltage transformer.

4. The voltage transformer according to claim 2 or 3, characterized in that, The first energy storage subunit is configured to output the first power supply signal to the first driving unit when the voltage transformer is in a shutdown state or an abnormal protection state.

5. The voltage converter of claim 4, wherein, The first energy storage subunit comprises a capacitor.

6. The voltage transformer of claim 1, wherein, The second energy storage subunit comprises a capacitor.

7. Voltage converter according to claim 1 or 6, characterized in that The power supply unit further comprises a voltage stabilizing diode, which is connected with the first energy storage subunit in parallel.

8. The voltage transformer of any one of claims 1 to 3, 5 to 6, characterized in that, The discharge control subunit comprises a control subunit and a discharge subunit, a first end of the discharge subunit is connected with a first end of the first energy storage subunit, and a second end of the discharge subunit is grounded; The control subunit is configured to output a first control signal to the discharge subunit when the voltage transformer is in a shutdown state or an abnormal protection state, and the first control signal is used to control the discharge subunit to be turned on; The discharge subunit is configured to connect the first end of the first energy storage subunit with the ground level under the control of the first control signal; The control subunit is further configured to output a second control signal to the discharge subunit after a first time length of the first control signal is input to the discharge subunit, and the second control signal is used to control the discharge subunit to be turned off; The discharge subunit is further configured to disconnect the first end of the first energy storage subunit from the ground level under the control of the second control signal.

9. Voltage converter according to claim 8, characterized in that The discharge subunit comprises a photosensitive subunit, and the control subunit comprises a first port, a second port, a third energy storage subunit and a light-emitting subunit; The first port of the control subunit, the light-emitting subunit, the third energy storage subunit and the second port of the control subunit are connected in series; The first port of the control subunit is configured to receive a first electric signal when the voltage transformer is in a shutdown state or an abnormal protection state; The second port of the control subunit is configured to receive a second electric signal when the voltage transformer is in a shutdown state or an abnormal protection state, and a voltage of the first electric signal is higher than a voltage of the second electric signal; The third energy storage subunit is configured to be charged during a process that the first port of the control subunit receives the first electric signal and the second port of the control subunit receives the second electric signal; The light-emitting subunit is configured to output a light signal to the photosensitive subunit before the third energy storage subunit is fully charged; The photosensitive subunit is configured to connect the first end of the first energy storage subunit with the ground level after receiving the light signal; The light-emitting subunit is further configured to stop outputting the light signal to the photosensitive subunit after the third energy storage subunit is fully charged; The photosensitive subunit is further configured to disconnect the first end of the first energy storage subunit from the ground level after the light-emitting subunit stops outputting the light signal.

10. The voltage converter of claim 9, wherein, The second port is connected with a first pin of a primary side control unit of the voltage transformer, and a state of the first pin indicates an operating state of the primary side control unit.

11. Voltage converter according to claim 9 or 10, characterized in that The light-sensitive unit comprises a light-sensitive triode, and the light-emitting unit comprises a light-emitting diode, a positive electrode of the light-emitting diode being connected with the first port of the control sub-unit, and a negative electrode of the light-emitting diode being connected with the third energy storage sub-unit.

12. The voltage transformer of claim 9, wherein, The third energy storage sub-unit comprises a capacitor.

13. The voltage transformer of any one of claims 1 to 3, 5 to 6, 9 to 10, 12, characterized in that, The voltage transformer further comprises a transformer, and the power supply unit further comprises a conduction control sub-unit, one end of the conduction control sub-unit being connected with a second secondary side winding of the transformer, and the other end of the conduction control sub-unit being connected with the first end of the resistor unit. The conduction control sub-unit is configured to conduct the second secondary side winding of the transformer and the first end of the resistor unit when the voltage transformer is in an open state, and to shut off the second secondary side winding of the transformer and the first end of the resistor unit when the voltage transformer is in a closed state or an abnormal protection state.

14. The voltage transformer of claim 13, wherein, The conduction control sub-unit comprises a diode, a positive electrode of the diode being connected with the second secondary side winding, and a negative electrode of the diode being connected with the first end of the resistor unit.

15. An electronic device, comprising: The electronic device comprises the voltage transformer according to any one of claims 1 to 14, and the voltage transformer is configured to provide a voltage transformation function for the electronic device.

16. The electronic device of claim 15, wherein, The electronic device comprises any one of a router, a switch, a server, and a wireless base station.

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