Power supply device

Abstract

The invention discloses a power supply device. The power supply device comprises a power supply, a load, a first switching circuit, an enabling control unit and a driving unit. The enable control unit is used for outputting an enable control signal. The driving unit comprises a half-bridge driving circuit and a charge pump circuit, the first signal input end of the half-bridge driving circuit is connected with the signal output end of the enabling control unit, the floating power supply end of the half-bridge driving circuit is connected with the charge pump circuit, and the first driving output end of the half-bridge driving circuit is connected with the grid electrode of each switching tube; the floating ground end of the half-bridge drive circuit is connected with the source electrode of each switch tube. Through the mode, driving power supply can be carried out on the switching tube in the first switching circuit by combining the charge pump principle of the simple half-bridge driving circuit and the charge pump circuit, a complicated isolation power supply does not need to be additionally added to provide driving power supply for the switching tube in the first switching circuit, the realization is simple, and the cost is relatively low.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a power supply device. Background Art

[0002] A safety switch is usually added between the power supply and the load to protect the power supply and the load. At present, the safety switch usually uses a PMOS switch tube or an NMOS switch tube. The PMOS switch tube has the significant advantage of not requiring an additional drive power supply, but it has high on-resistance, is expensive, and is difficult to select. The advantages and disadvantages of the NMOS switch tube are opposite to those of the PMOS switch tube. The biggest problem is that it requires a separate drive power supply with a higher output voltage than the power supply.

[0003] In the related art, the driving power supply of the NMOS switch tube in the safety switch is usually realized by isolating the DC / DC. However, the topological structure of the isolated DC / DC is relatively complex, and the method of taking power from the secondary power circuit of the isolated DC / DC has high requirements for PCB layout and wiring, which is easy to introduce signal crosstalk. Summary of the invention

[0004] The main technical problem solved by the present application is to provide a power supply device, which can combine a simple half-bridge drive circuit and a charge pump circuit's charge pump principle to drive and supply power to the switch tube in the first switch circuit, and is simple to implement and low in cost.

[0005] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a power supply device, which includes: a power supply and a load; a first switch circuit, the first switch circuit includes a preset number of switch tubes, and the preset number of switch tubes are connected between the power supply and the load; an enable control unit, the enable control unit is used to output an enable control signal; a drive unit, the drive unit includes a half-bridge drive circuit and a charge pump circuit, the first signal input terminal of the half-bridge drive circuit is connected to the signal output terminal of the enable control unit, the floating power supply terminal of the half-bridge drive circuit is connected to the charge pump circuit, and the first drive output terminal of the half-bridge drive circuit is connected to the floating power supply terminal of the half-bridge drive circuit. The end is connected to the gate of each switch tube, and the floating ground end of the half-bridge drive circuit is connected to the source of each switch tube; wherein, when the enable control signal is a first level signal, the charge pump circuit is used to provide a floating power supply voltage for the floating power supply end, and the first drive output end is configured to output a first drive voltage, and the voltage difference between the first drive voltage and the floating ground end is greater than the threshold voltage of each switch tube, so that the first switch circuit is turned on; when the enable control signal is a second level signal, the first drive output end is configured to output a second drive voltage, and the voltage difference between the second drive voltage and the floating ground end is less than the threshold voltage of each switch tube, so that the first switch circuit is turned off.

[0006] Optionally, the charge pump circuit includes a charge and discharge circuit, a first power supply, a first diode, a second diode, a third diode, a first capacitor, a second capacitor and a first resistor; the voltage output end of the charge and discharge circuit is connected to the second signal input end of the half-bridge drive circuit, and the charge and discharge circuit is used to alternately charge and discharge, and alternately provide a charging voltage and a discharging voltage to the second signal input end of the half-bridge drive circuit; the first power supply is connected to the power supply end of the half-bridge drive circuit and the anode of the first diode, the cathode of the first diode is connected to the first end of the first capacitor, the floating power supply end and the cathode of the second diode, the anode of the second diode is connected to the cathode of the third diode and the first end of the second capacitor, the anode of the third diode is connected to the second end of the first capacitor and the floating ground end, and the The second end of the second capacitor is connected to the first end of the first resistor, and the second end of the first resistor is connected to the second drive output end of the half-bridge drive circuit; when the charge-discharge circuit is charged and the charging voltage meets the voltage condition, the second drive output end is configured to output a third level signal, and the second drive output end, the first resistor, the second capacitor, the second diode and the first capacitor form a first charging path to charge the first capacitor; when the charge-discharge circuit is discharged and the discharge voltage does not meet the voltage condition, the second drive output end is configured to output a fourth level signal, and the first power supply, the first diode, the first capacitor, the third diode, the second capacitor, the first resistor and the second drive output end form a second charging path to charge the first capacitor, and the level of the fourth level signal is lower than the level of the third level signal.

[0007] Optionally, the charge and discharge circuit includes a second resistor, a third resistor, a second switch circuit and a third capacitor, the first end of the second resistor is used to connect to the second power supply, the second end of the second resistor is connected to the first end of the third resistor, the first end of the third capacitor and the second signal input end of the half-bridge drive circuit, the second end of the third resistor is connected to the first end of the second switch circuit, the second end of the second switch circuit and the second end of the third capacitor are both grounded, and the control end of the second switch circuit is used to alternately receive a fifth level signal and a sixth level signal; wherein, when the control end of the second switch circuit receives the fifth level signal, the second switch circuit is configured to be in an off state, and the second power supply charges the third capacitor to provide a charging voltage for the second signal input end of the half-bridge drive circuit; when the control end of the second switch circuit receives the sixth level signal, the second switch circuit is configured to be in an on state, and the third capacitor discharges to provide a discharge voltage for the second signal input end of the half-bridge drive circuit, and the level of the sixth level signal is higher than the level of the fifth level signal.

[0008] Optionally, the control end of the second switch circuit is connected to the second drive output end.

[0009] Optionally, the charge and discharge circuit further includes a fourth diode, a cathode of the fourth diode is connected to the signal output terminal of the enable control unit, and an anode of the fourth diode is connected to the second end of the second resistor.

[0010] Optionally, the first switch circuit includes a first switch tube and a second switch tube, the drain of the first switch tube is connected to the power supply, the source of the first switch tube is connected to the source of the second switch tube, and the drain of the second switch tube is connected to the load.

[0011] Optionally, the enabling control unit includes a sampling subunit and a fault detection subunit, the sampling input end of the sampling subunit is connected to the power supply line between the power supply and the load, the input end of the fault detection subunit is connected to the signal output end of the sampling subunit, and the fault detection subunit is used to perform fault detection using the sampling data output by the sampling subunit, and output a corresponding enabling control signal; wherein, when the fault detection subunit does not detect a fault, the enabling control signal is a first level signal, and when the fault detection subunit detects a fault, the enabling control signal is a second level signal.

[0012] Optionally, the sampling subunit includes at least one of a first voltage sampling circuit, a second voltage sampling circuit, a first current sampling circuit, and a second current sampling circuit, the first voltage sampling circuit is used to obtain a first voltage between the first switching circuit and the load, the second voltage sampling circuit is used to obtain a second voltage between the power supply and the first switching circuit, the first current sampling circuit is used to obtain a first current flowing into the load, and the second current sampling circuit is used to obtain a second current flowing out of the load.

[0013] Optionally, the sampling subunit includes a first voltage sampling circuit, the first voltage sampling circuit includes a first voltage dividing resistor, a second voltage dividing resistor and a third switching circuit, the first end of the first voltage dividing resistor is connected to the sampling input end of the first voltage sampling circuit, the second end of the first voltage dividing resistor is connected to the second voltage dividing resistor and the sampling output end of the first voltage sampling circuit, and the third switching circuit is connected to the sampling path between the sampling input end of the first voltage sampling circuit and the sampling output end of the first voltage sampling circuit; wherein, when the power supply is not in sleep mode, the third switching circuit is configured to be in an on state, and when the power supply is in sleep mode, the third switching circuit is configured to be in an off state.

[0014] Optionally, the fault detection subunit includes at least one comparison circuit, the detection signal input terminal of each comparison circuit is respectively connected to the corresponding sampling circuit output terminal, the reference signal input terminal of each comparison circuit is respectively connected to the corresponding reference voltage providing circuit, and the output terminal of each comparison circuit is connected.

[0015] Optionally, the power supply device also includes a controller, and a first control signal output terminal of the controller is connected to the first signal input terminal of the half-bridge drive circuit; before the power supply works, the controller is used to output a first level signal to the first signal input terminal of the half-bridge drive circuit, obtain a second voltage between the power supply and the first switching circuit, and judge whether the first switching circuit is normally turned on based on whether the second voltage meets a first preset voltage condition; and the controller is also used to output a second level signal to the first signal input terminal of the half-bridge drive circuit after judging that the first switching circuit is normally turned on, and judge whether the first switching circuit is normally turned off based on whether the second voltage meets a second preset voltage condition.

[0016] Optionally, the voltage output end of the power supply is connected to the first end of the fourth capacitor, and the second end of the fourth capacitor is grounded; the power supply device also includes a fourth switching circuit, the first end of the fourth switching circuit is connected to the first end of the fourth capacitor, the second end of the fourth switching circuit is grounded, and the control end of the fourth switching circuit is connected to the second control signal output end of the controller; after determining that the first switching circuit is normally turned on, and before outputting the second level signal to the first signal input end of the half-bridge drive circuit, the controller is also used to output a discharge control signal to the control end of the fourth switching circuit, so that the fourth switching circuit is in a conducting state, so that the fourth capacitor discharges energy.

[0017] Optionally, the power supply is a vehicle-mounted power converter, which is used to convert the output voltage of the power battery, and the load is a vehicle-mounted battery or a vehicle-mounted electrical appliance.

[0018] In the above scheme, the power supply device includes a power supply, a load, a first switch circuit, an enable control unit and a drive unit. The enable control unit is used to output an enable control signal. The drive unit includes a half-bridge drive circuit and a charge pump circuit. The first signal input terminal of the half-bridge drive circuit is connected to the signal output terminal of the enable control unit, the floating power supply terminal of the half-bridge drive circuit is connected to the charge pump circuit, the first drive output terminal of the half-bridge drive circuit is connected to the gate of each switch tube, and the floating ground terminal of the half-bridge drive circuit is connected to the source of each switch tube. When the enable control signal is a first level signal, the charge pump circuit is used to provide a floating power supply voltage to the floating power supply terminal, the first drive output terminal is configured to output a first drive voltage, and the voltage difference between the first drive voltage and the floating ground terminal is greater than the threshold voltage of each switch tube, so that the first switch circuit is turned on; when the enable control signal is a second level signal, the first drive output terminal is configured to output a second drive voltage, and the voltage difference between the second drive voltage and the floating ground terminal is less than the threshold voltage of each switch tube, so that the first switch circuit is turned off. In this way, a simple half-bridge drive circuit and the charge pump principle of the charge pump circuit can be combined to provide driving power for the switch tube in the first switch circuit. There is no need to add an additional complex isolated power supply to provide driving power for the switch tube in the first switch circuit. The implementation is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a circuit structure diagram of an embodiment of a power supply device provided by the present application;

[0020] Figure 2 is a schematic diagram of the circuit structure of the drive unit provided by the present application;

[0021] Figure 3 is a schematic diagram of relevant voltage waveforms when the charge pump circuit provided by the present application is enabled;

[0022] Figure 4 is a circuit structure schematic diagram of a first switch circuit provided in the present application;

[0023] Figure 5 is a circuit structure diagram of another embodiment of the power supply device provided by the present application;

[0024] Figure 6 is a circuit structure diagram of a first voltage sampling circuit provided by the present application;

[0025] Figure 7 is a circuit structure diagram of a second voltage sampling circuit provided by the present application;

[0026] Figure 8 is a circuit structure diagram of a first current sampling circuit provided by the present application;

[0027] Fig. 9is a schematic diagram of the circuit structure of the fault detection subunit provided by the present application;

[0028] Fig.10 It is a circuit structure diagram of another embodiment of the power supply device provided in the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail below with reference to the accompanying drawings and examples.

[0030] It should be noted that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, "many" in this article means two or more than two; the term "many" in this article means at least two; the terms "first", "second", etc. in this article are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0031] See also Figure 1 , Figure 1 Schematic diagram of the circuit structure of an embodiment of the power supply device provided by the present application. Figure 1 As shown, the power supply device includes a power supply 10, a load 20, a first switch circuit 30, an enabling control unit 40 and a driving unit.

[0032] The power supply 10 is used to supply power to the load 20. Taking the vehicle scenario as an example, the power supply 10 is an on-board power converter (on-board DC / DC power supply). The on-board power converter is used to convert the output voltage of the power battery, converting the high-voltage direct current of the power battery into a low-voltage direct current (such as 12V, 21V, 18V, etc.) output to supply power to the load 20 in the vehicle. Exemplarily, the load 20 is an on-board battery or an on-board electrical appliance.

[0033] The first switch circuit 30 includes a preset number of switch tubes, and the preset number of switch tubes are connected between the power supply 10 and the load 20 to form a safety switch between the power supply 10 and the load 20. The preset number can be one or two, and this embodiment does not specifically limit this. For each switch tube in the first switch circuit 30, the switch tube is turned on when the voltage difference between its gate voltage and the source voltage is greater than the threshold voltage, and is turned off when the voltage difference between its gate voltage and the source voltage is less than the threshold voltage. The switch tubes in the first switch circuit 30 are all NMOS, or the switch tubes in the first switch circuit 30 are SiC MOS, GaN and other switch tubes with the same function.

[0034] The enabling control unit 40 is used to output an enabling control signal. The enabling control signal is a first level signal or a second level signal. In a specific application, the first level signal is a high level signal, and the second level signal is a low level signal.

[0035] The driving unit includes a half-bridge driving circuit 50 and a charge pump circuit 60. The first signal input terminal of the half-bridge driving circuit 50 is connected to the signal output terminal of the enable control unit 40, the floating power supply terminal of the half-bridge driving circuit 50 is connected to the charge pump circuit 60, the first driving output terminal of the half-bridge driving circuit 50 is connected to the gate of each switch tube in the first switch circuit 30, and the floating ground terminal of the half-bridge driving circuit 50 is connected to the source of each switch tube in the first switch circuit 30.

[0036] Among them, when the enable control signal is a first level signal, the charge pump circuit 60 is used to provide a floating power supply voltage for the floating power supply terminal, and the first drive output terminal is configured to output a first drive voltage. The voltage difference between the first drive voltage and the floating ground terminal is greater than the threshold voltage of each switch tube, so that each switch tube in the first switch circuit 30 is turned on, and then the first switch circuit 30 is turned on.

[0037] When the enable control signal is a second level signal, the first drive output terminal is configured to output a second drive voltage, and the voltage difference between the second drive voltage and the floating ground terminal is less than the threshold voltage of each switch tube, so that each switch tube in the first switch circuit 30 is turned off, thereby turning off the first switch circuit 30.

[0038] In this embodiment, the power supply device includes a power supply, a load, a first switch circuit, an enable control unit and a drive unit. The enable control unit is used to output an enable control signal. The drive unit includes a half-bridge drive circuit and a charge pump circuit. The first signal input terminal of the half-bridge drive circuit is connected to the signal output terminal of the enable control unit, the floating power supply terminal of the half-bridge drive circuit is connected to the charge pump circuit, the first drive output terminal of the half-bridge drive circuit is connected to the gate of each switch tube, and the floating ground terminal of the half-bridge drive circuit is connected to the source of each switch tube. When the enable control signal is a first level signal, the charge pump circuit is used to provide a floating power supply voltage to the floating power supply terminal, the first drive output terminal is configured to output a first drive voltage, and the voltage difference between the first drive voltage and the floating ground terminal is greater than the threshold voltage of each switch tube, so that the first switch circuit is turned on; when the enable control signal is a second level signal, the first drive output terminal is configured to output a second drive voltage, and the voltage difference between the second drive voltage and the floating ground terminal is less than the threshold voltage of each switch tube, so that the first switch circuit is turned off. In this way, a simple half-bridge drive circuit and the charge pump principle of the charge pump circuit can be combined to provide driving power for the switch tube in the first switch circuit. There is no need to add an additional complex isolated power supply to provide driving power for the switch tube in the first switch circuit. The implementation is simple and the cost is low.

[0039] See also Figure 2 , Figure 2 is a schematic diagram of the circuit structure of the drive unit provided in this application. Figure 2 As shown, the driving unit includes a half-bridge driving circuit 50 and a charge pump circuit.

[0040] The half-bridge driving circuit 50 can be an integrated half-bridge driving chip or composed of discrete components. The internal circuit structure and related working principle of the half-bridge driving circuit 50 can refer to the internal circuit structure and related working principle of the existing half-bridge driving chip, and will not be elaborated in detail in this embodiment.

[0041] The charge pump circuit includes a charge and discharge circuit 61, a first power source (i.e. Figure 2 12V_AUX in the circuit), a first diode D1, a second diode D2, a third diode D5, a first capacitor C1, a second capacitor C4 and a first resistor R8.

[0042] The voltage output end of the charge and discharge circuit 61 is connected to the second signal input end (LI pin) of the half-bridge drive circuit 50. The first power supply is connected to the power supply end (corresponding to the VDD pin) of the half-bridge drive circuit 50 and the anode of the first diode D1, the cathode of the first diode D1 is connected to the first end of the first capacitor C1, the floating power supply end (corresponding to the HB pin) of the half-bridge drive circuit 50 and the cathode of the second diode D2, the anode of the second diode D2 is connected to the cathode of the third diode D5 and the first end of the second capacitor C4, the anode of the third diode D5 is connected to the second end of the first capacitor C1 and the floating ground end (corresponding to the HS pin) of the half-bridge drive circuit 50, the second end of the second capacitor C4 is connected to the first end of the first resistor R8, and the second end of the first resistor R8 is connected to the second drive output end (corresponding to the LO pin) of the half-bridge drive circuit 50. In addition, the first signal input end (corresponding to the HI pin) of the half-bridge drive circuit 50 is connected to the signal output end of the enable control unit 40 for receiving the enable control signal (Oring_EN). The first driving output terminal (corresponding to the HO pin) of the half-bridge driving circuit 50 is used to connect to the gate of each switch tube in the first switch circuit 30, and the floating ground terminal of the half-bridge driving circuit 50 is used to connect to the source of each switch tube in the first switch circuit 30 ( Figure 2 The first switch circuit 30 is not shown.

[0043] The charge and discharge circuit 61 is used for alternately charging and discharging, and alternately provides a charging voltage and a discharging voltage to the second signal input terminal of the half-bridge driving circuit 50 .

[0044] When the charge and discharge circuit 61 is charged and the charging voltage meets the voltage condition, the second drive output end of the half-bridge drive circuit 50 is configured to output a third level signal, and the second drive output end of the half-bridge drive circuit 50, the first resistor R8, the second capacitor C4, the second diode D2 and the first capacitor C1 form a first charging path to charge the first capacitor C1.

[0045] When the charge and discharge circuit 61 discharges and the discharge voltage does not meet the voltage condition, the second drive output terminal is configured to output a fourth level signal, and 12V_AUX, the first diode D1, the first capacitor C1, the third diode D5, the second capacitor C4, the first resistor R8 and the second drive output terminal of the half-bridge drive circuit 50 form a second charging path to charge the first capacitor C1.

[0046] In a specific application, the third level signal is a high level signal, and the fourth level signal is a low level signal.

[0047] In a specific application, the aforementioned voltage condition is: the voltage input to the second signal input terminal of the half-bridge driving circuit 50 is greater than a voltage threshold.

[0048] The charge and discharge circuit 61 further includes a second resistor R1, a third resistor R7, a second switch circuit 611 and a third capacitor C2. The first end of the second resistor R1 is used to connect to the second power source ( Figure 2 The first end of the second power supply and the first power supply may be the same power supply, or the second power supply and the first power supply may be different power supplies.

[0049] The control end of the second switch circuit 611 is used to alternately receive the fifth level signal and the sixth level signal. When the control end of the second switch circuit 611 receives the fifth level signal, the second switch circuit 611 is configured to be in an off state, and the second power supply charges the third capacitor C2 to provide a charging voltage for the second signal input end of the half-bridge drive circuit 50. When the control end of the second switch circuit 611 receives the sixth level signal, the second switch circuit 611 is configured to be in an on state, and the third capacitor C2 is discharged to provide a discharge voltage for the second signal input end of the half-bridge drive circuit 50.

[0050] In a specific application, the second switch circuit 611 includes a third switch tube Q3. Exemplarily, the third switch tube Q3 is an NMOS tube, the fifth level signal is a low level signal, and the sixth level signal is a high level signal.

[0051] In a specific application, the control terminal of the second switch circuit 611 is connected to the second driving output terminal of the half-bridge driving circuit 50. That is, the charging or discharging of the charge-discharge circuit 61 is controlled by the output signal of the second driving output terminal of the half-bridge driving circuit 50.

[0052] In this embodiment, when the charge pump circuit is enabled, the process of charging the first capacitor C1 through the aforementioned first charging path and the process of charging the first capacitor C1 through the aforementioned second charging path are cyclically performed until the voltage of the first capacitor C1 remains stable, so as to provide a stable driving power supply for the first driving output terminal of the half-bridge driving circuit 50.

[0053] Figure 3 Schematic diagram of relevant voltage waveforms when the charge pump circuit provided by the present application is enabled. Figure 3 The voltage waveform of (HB-HS), the voltage waveform of the third capacitor C2, the voltage waveform of the first drive output terminal LO of the half-bridge drive circuit 50, and the voltage waveform of the first signal input terminal LI of the half-bridge drive circuit 50 are shown in the figure. The (HB-HS) is actually the voltage across the first capacitor C1. When the enable control signal input to the half-bridge drive circuit 50 is a high-level signal, the voltage at the first drive output terminal of the half-bridge drive circuit 50 is equal to the voltage at the floating power supply terminal of the half-bridge drive circuit 50, so that the first drive output terminal of the half-bridge drive circuit 50 and the floating ground terminal of the half-bridge drive circuit 50 form a voltage difference greater than the threshold voltage of the switch tube, thereby turning on each switch tube in the first switch circuit 30, thereby realizing driving power supply for each switch tube in the first switch circuit 30.

[0054] Optionally, in this embodiment, the charge and discharge circuit 61 may further include a fourth diode D3, the cathode of the fourth diode D3 is connected to the signal output terminal of the enable control unit 40, and the anode of the fourth diode D3 is connected to the second end of the second resistor R1. The fourth diode D3 is a Schottky diode.

[0055] When the input enable control signal (ORring_EN) is a high level signal, the charge pump circuit is enabled to alternately charge the first capacitor C1. At this time, the first drive output terminal of the half-bridge drive circuit 50 outputs the first drive voltage, so that the first switch circuit 30 is turned on.

[0056] When the input enable control signal (ORring_EN) is a low level signal, the second signal input terminal of the half-bridge driving circuit 50 is continuously pulled down through the fourth diode D3, and the charge pump circuit is not enabled to alternately charge the first capacitor C1. At this time, the first driving output terminal of the half-bridge driving circuit 50 outputs the second driving voltage, so that the first switch circuit 30 is turned off.

[0057] By providing the fourth diode D3 , when the input enable control signal (ORring_EN) is a low level signal, the first capacitor C1 is not alternately charged, thereby saving static power consumption of the driving unit.

[0058] Optionally, in this embodiment, the charge pump circuit may further include a fifth diode D4. The cathode of the fifth diode D4 is connected to the first end of the first capacitor C1, and the anode of the fifth diode D4 is connected to the second end of the first capacitor C1. The fifth diode D4 is a voltage stabilizing diode, which is used to prevent the voltage of the first capacitor C1 from being too high.

[0059] See also Figure 4 , Figure 4 is a schematic diagram of the circuit structure of the first switch circuit provided by the present application. Figure 4 As shown, the first switch circuit 30 includes a first switch tube Q1 and a second switch tube Q2. The drain of the first switch tube Q1 is used to connect to the power supply 10 ( Figure 4 The source of the first switch tube Q1 is connected to the source of the second switch tube Q2, and the drain of the second switch tube Q2 is used to connect to the load 20 ( Figure 4 The gate of the first switch tube Q1 and the gate of the second switch tube Q2 are both connected to the first drive output terminal of the half-bridge drive circuit 50. The source of the first switch tube Q1 and the source of the second switch tube Q2 are both connected to the floating ground terminal of the half-bridge drive circuit 50.

[0060] In this embodiment, the first switch tube Q1 and the second switch tube Q2 are connected in series back to back as a safety switch. Among them, the first switch tube Q1 plays a role in reverse polarity protection and output cutoff. When the first switch tube Q1 is turned off, the path for the power supply 10 to output current to the load 20 (such as a battery) is cut off, thereby avoiding the output of abnormal voltage to the load 20. At the same time, if the positive and negative poles are reversed between the load 20 (such as a battery) and the power supply 10 (that is, the positive pole of the load 20 is connected to the negative pole of the power supply 10, and the negative pole of the load 20 is connected to the positive pole of the power supply 10), the turned-off first switch tube Q1 can block the reverse polarity current to prevent the large current from burning the power supply 10 or the load 20.

[0061] The second switch tube Q2 plays a role in preventing current backflow. When the power supply 10 experiences a voltage drop or an output short circuit, the turned-off second switch tube Q2 can block the backflow current from the load 20 (such as a battery) flowing into the power supply 10.

[0062] Optionally, the first switch circuit 30 may further include a resistor R3, a resistor R4, a resistor R5, and a resistor R6. If the gate G and the source S of the first switch tube Q1 and the second switch tube Q2 are suspended, it is easy to be disturbed so that the first switch tube Q1 and the second switch tube Q2 are mis-conducted, so the resistor R3 and the resistor R4 are used to make the first switch tube Q1 and the second switch tube Q2 in the off state by default. The resistor R5 and the resistor R6 are the gate drive resistors of the first switch tube Q1 and the second switch tube Q2, respectively, and are used to control the switching speed of the first switch tube Q1 and the second switch tube Q2, respectively.

[0063] See also Figure 5 , Figure 5 It is a circuit structure diagram of another embodiment of the power supply device provided in the present application. Figure 5 In the power supply device shown, the enabling control unit includes a sampling subunit 41 and a fault detection subunit 42. The sampling input end of the sampling subunit 41 is connected to the power supply line between the power supply and the load. The input end of the fault detection subunit 42 is connected to the signal output end of the sampling subunit, and the fault detection subunit 42 is used to perform fault detection using the sampling data output by the sampling subunit 41, and output a corresponding enabling control signal.

[0064] Wherein, when the fault detection subunit 42 does not detect a fault, the enable control signal is a first level signal; when the fault detection subunit 42 detects a fault, the enable control signal is a second level signal.

[0065] In this embodiment, the sampling subunit 41 includes at least one of a first voltage sampling circuit, a second voltage sampling circuit, a first current sampling circuit, and a second current sampling circuit ( Figure 4 The sampling circuits are not shown in the figure). The first voltage sampling circuit is used to obtain a first voltage between the first switch circuit and the load, the second voltage sampling circuit is used to obtain a second voltage between the power supply and the first switch circuit, the first current sampling circuit is used to obtain a first current flowing into the load, and the second current sampling circuit is used to obtain a second current flowing out of the load.

[0066] See also Figure 6 , Figure 6 is a schematic diagram of the circuit structure of the first voltage sampling circuit provided by the present application. Figure 6 As shown, the first voltage sampling circuit includes a first voltage dividing resistor R13, a second voltage dividing resistor R17 and a third switch circuit 411. The first end of the first voltage dividing resistor R13 is connected to the sampling input end ( Figure 6 The second end of the first voltage-dividing resistor R13 is connected to the second voltage-dividing resistor R17 and the sampling output end ( Figure 6The third switch circuit 411 is connected to a sampling path between a sampling input terminal of the first voltage sampling circuit and a sampling output terminal of the first voltage sampling circuit. When the power supply is not in sleep mode, the third switch circuit 411 is configured to be in an on state, and when the power supply is in sleep mode, the third switch circuit 411 is configured to be in an off state.

[0067] In one implementation scenario, the power supply is a vehicle-mounted DC / DC power supply, and the vehicle-mounted DC / DC power supply is provided with a corresponding controller ( Figure 6 (not shown), the controller is used to control the switch tube in the vehicle-mounted DC / DC power supply to perform voltage conversion. The control end of the third switch circuit 411 is connected to the controller. When the vehicle is locked and stationary, the vehicle-mounted DC / DC power supply is powered off and dormant. At this time, the controller will output a default output low-level signal to the control end of the third switch circuit 411 to configure the third switch circuit 411 to an off state, thereby controlling the first voltage sampling circuit not to perform sampling. When the vehicle-mounted DC / DC power supply is not dormant, the controller will output a default output high-level signal to the control end of the third switch circuit 411 to configure the third switch circuit 411 to an on state, thereby controlling the first voltage sampling circuit to perform sampling.

[0068] It should be noted that Figure 6 Although the resistor R12 is also connected to the sampling path between the sampling input terminal and the sampling output terminal of the first voltage sampling circuit, it can be approximately considered not to participate in the voltage division because of its small resistance.

[0069] In one embodiment, the first end of the third switch circuit 411 is connected to the sampling input end of the first voltage sampling circuit, the second end of the third switch circuit 411 is connected to the first end of the first voltage-dividing resistor R13, and the control end of the third switch circuit 411 is connected to the control signal output end of the controller. When the control end of the third switch circuit 411 receives a high-level signal, the third switch circuit 411 is configured to be in an on state, at which time the first voltage sampling circuit is connected and voltage sampling can be performed. When the control end of the third switch circuit 411 receives a low-level signal, the third switch circuit 411 is configured to be in an off state, at which time the first voltage sampling circuit is not connected and voltage sampling cannot be performed.

[0070] In a specific application, the third switch circuit 411 includes a fifth switch tube Q5 and a sixth switch tube Q6. A first end of the fifth switch tube Q5 is connected to a sampling input end of the first voltage sampling circuit, a second end of the fifth switch tube Q5 is connected to a first end of a first voltage-dividing resistor R13, a control end of the fifth switch tube Q5 is connected to a first end of a sixth switch tube Q6, a second end of the sixth switch tube Q6 is grounded, and a control end of the sixth switch tube Q6 is a control end of the third switch circuit 411.

[0071] Exemplarily, the fifth switch tube Q5 is a PMOS tube, and the sixth switch tube Q6 is an NMOS tube. When a high-level signal is input to the control end of the sixth switch tube Q6, the sixth switch tube Q6 is turned on, so that the voltage of the control end of the fifth switch tube Q5 is pulled down, thereby turning on the fifth switch tube Q5. When a low-level signal is input to the control end of the sixth switch tube Q6, the sixth switch tube Q6 is turned off, and the fifth switch tube Q5 is also turned off.

[0072] When the load is a battery or other type of power source, if the power supply is dormant and powered off, and the third switch circuit 411 is not provided on the sampling path of the first voltage sampling circuit, the first voltage-dividing resistor R13 and the second voltage-dividing resistor R17 will divide the voltage of the battery or other type of power source, thereby generating static power consumption. By controlling the first voltage sampling circuit not to be connected when the power supply is dormant and powered off, the static power consumption generated by the circuit can be reduced, and the energy consumption of the battery or other type of power source due to static power consumption can be avoided.

[0073] Optionally, the sampling output terminal of the first voltage sampling circuit may also be connected to the sampling terminal of the controller. Considering that the pin voltage of the controller is usually 3.3V, if the pin voltage input to the controller is too high, the controller may be damaged. Therefore, a limiting diode D6 may be further designed at the sampling output terminal of the first voltage sampling circuit, and the limiting diode D6 is used to limit the voltage of the sampling output terminal of the first voltage sampling circuit to within 3.3V.

[0074] See also Figure 7 , Figure 7 is a schematic diagram of the circuit structure of the second voltage sampling circuit provided by the present application. Figure 7 As shown, the second voltage sampling circuit includes: a third voltage dividing resistor R19 and a fourth voltage dividing resistor R22. The first end of the third voltage dividing resistor R19 is the sampling input end of the second voltage sampling circuit (corresponding to Figure 7 The second end of the third voltage-dividing resistor R19 and the first end of the fourth voltage-dividing resistor R22 and the output end of the second voltage sampling circuit (corresponding to Figure 7 A second end of the fourth voltage dividing resistor R22 is connected to an end of the fourth voltage dividing resistor R22 that outputs the second voltage sampling value VSEN_VIN. A second end of the fourth voltage dividing resistor R22 is grounded.

[0075] Optionally, a third voltage-dividing resistor R19 and a fourth voltage-dividing resistor R22 with higher resistance values ​​may be selected to reduce static power consumption.

[0076] Optionally, the sampling output terminal of the second voltage sampling circuit can also be connected to the sampling terminal of the controller. A limiting diode D8 can be further designed at the sampling output terminal of the second voltage sampling circuit, and the limiting diode D8 is used to limit the voltage of the sampling output terminal of the second voltage sampling circuit to within 3.3V to prevent the controller from being damaged due to a large input voltage.

[0077] See also Figure 8 , Figure 8 is a circuit structure diagram of the first current sampling circuit provided by the present application. Figure 8 As shown, the first current sampling circuit includes a shunt resistor R27 and a current sampling amplifier U2. The shunt resistor R27 is connected in series between the first switch circuit and the load. The resistance of the shunt resistor R27 is relatively small, generally less than 1mΩ, and can be achieved by connecting multiple resistors in parallel. The shunt resistor R27 is used to convert hundreds of amperes of current into a voltage signal of tens of millivolts, which is then converted into a first current sampling value LVDC_OUT_ISEN through a current sampling amplifier U2 for gain amplification and voltage biasing.

[0078] The second current sampling circuit is similar to the first current sampling circuit and will not be described in detail here.

[0079] In one embodiment, the fault detection subunit is a controller. The controller can obtain sampling data of the first voltage sampling circuit to detect whether there is an input overvoltage fault, obtain sampling data of the second voltage sampling circuit to detect whether there is an output overvoltage fault, obtain sampling data of the first current sampling circuit to detect whether there is an output overcurrent fault, and obtain sampling data of the second current sampling circuit to detect whether there is a reverse overcurrent fault. When at least one of the input overvoltage fault, the output overvoltage fault, the output overcurrent fault and the reverse overcurrent fault exists, the controller outputs a second level signal to the driving unit to control the first switch circuit to turn off.

[0080] In another embodiment, considering that the real-time performance of the software fault detection solution is not high, fault detection can be implemented by hardware circuits to improve the real-time performance of fault detection. The fault detection subunit includes at least one comparison circuit, the detection signal input end of each comparison circuit is respectively connected to the output end of the corresponding sampling circuit, the reference signal input end of each comparison circuit is respectively connected to the corresponding reference voltage providing circuit, and the output end of each comparison circuit is connected and used as the output end of the fault detection subunit. The reference voltage providing circuit corresponding to each comparison circuit is used to provide a corresponding protection threshold.

[0081] See also Fig. 9 , Fig. 9 Schematic diagram of the circuit structure of the fault detection subunit provided by the present application. Fig. 9As shown, the fault detection subunit includes a first comparison circuit 421, a second comparison circuit 422, a pull-up resistor R31 and a fifth switch circuit 423. Among them, the inverting input terminal of the first comparison circuit 421 is connected to the sampling output terminal of the first current sampling circuit, and is used to obtain the first current sampling value LVDC_OUT_ISEN, and compare the first current sampling value LVDC_OUT_ISEN with the set current protection threshold. The inverting input terminal of the second comparison circuit 422 is connected to the sampling output terminal of the first voltage sampling circuit, and is used to obtain the first voltage sampling value VSEN_VOUT, and compare the first voltage sampling value VSEN_VOUT with the set voltage protection threshold. The output terminal of the first comparison circuit 421 is connected to the output terminal of the second comparison circuit 422 and the first end of the pull-up resistor R31, and the second end of the pull-up resistor R31 is connected to the 3.3V power supply. The first end of the fifth switch circuit 423 is connected to the first end of the first pull-up resistor R31, the second end of the fifth switch circuit 423 is grounded, and the control end of the fifth switch circuit 423 is connected to the controller, and is used to receive the control signal ORing_CTRL.

[0082] When the first current sampling value LVDC_OUT_ISEN exceeds the corresponding current protection threshold, or the first voltage sampling value VSEN_VOUT exceeds the corresponding voltage protection threshold, the fault detection subunit outputs a low-level signal, that is, the output enable control signal ORing_EN is a low-level signal. At this time, the first switch circuit will be configured to be in the off state to cut off the connection between the power supply and the load.

[0083] When the first current sampling value LVDC_OUT_ISEN does not exceed the corresponding current protection threshold, and the first voltage sampling value VSEN_VOUT does not exceed the corresponding voltage protection threshold, that is, when the output overvoltage fault and the output overcurrent fault do not occur, the output end of the fault detection subunit is an open drain output. The level state of the output enable control signal ORing_EN is determined by the control signal ORing_CTRL. When the control signal ORing_CTRL is a low level signal, the fifth switch circuit 423 is configured to be in an off state, and the enable control signal ORing_EN output by the fault detection subunit is a high level signal; when the control signal ORing_CTRL is a high level signal, the fifth switch circuit 423 is configured to be in an on state, and the output enable control signal ORing_EN is a low level signal.

[0084] It should be noted that Fig. 9 In the figure, only the fault detection subunit including the first comparison circuit 421 and the second comparison circuit 422 is used as an example for illustrative description. In other implementations, the fault detection subunit may also change the number of comparison circuits according to actual fault detection requirements.

[0085] Optionally, in this embodiment, before the power supply 10 supplies power to the load 20, the first switch circuit 30 is self-checked to determine whether the first switch circuit 30 can be normally turned on and off, thereby further improving the reliability of the power supply device.

[0086] Before the power supply 10 works, the controller is used to output a first level signal to the first signal input terminal of the half-bridge drive circuit 50, obtain a second voltage between the power supply 10 and the first switch circuit 30, and judge whether the first switch circuit 30 is normally turned on based on whether the second voltage meets the first preset voltage condition; and the controller is also used to output a second level signal to the first signal input terminal of the half-bridge drive circuit 50 after judging that the first switch circuit 30 is normally turned on, and judge whether the first switch circuit 30 is normally turned off based on whether the second voltage meets the second preset voltage condition. Wherein, the first preset voltage condition is: LV_VIN = LV_VOUT-Vdrop. Wherein, LV_VIN represents the voltage at the output terminal of the power supply 10, LV_VOUT represents the voltage at the input terminal of the load 20, and Vdrop represents the conduction voltage drop of the first switch circuit 30. In practical applications, the first preset voltage condition can allow a certain error. The second preset voltage condition is: the voltage is within a preset voltage range. The preset voltage range is a value near 0.

[0087] Specifically, before the power supply 10 works, after controlling the first switch circuit 30 to turn on, if the second voltage meets the first preset voltage condition, it is judged that the first switch circuit 30 is normally turned on; if the second voltage does not meet the first preset voltage condition, it is judged that the first switch circuit 30 cannot be turned on normally.

[0088] Before the power supply 10 works, after controlling the first switch circuit 30 to be turned off, if the second voltage meets the second preset voltage condition, it is determined that the first switch circuit 30 is turned off normally; if the second voltage does not meet the second preset voltage condition, it is determined that the first switch circuit 30 cannot be turned off normally.

[0089] Fig.10 It is a circuit structure diagram of another embodiment of the power supply device provided in the present application. Fig.10 In the embodiment, the power supply device further includes a fourth capacitor C6 and a fifth capacitor C7. The voltage output terminal (LV_VIN) of the power supply 10 is connected to the first end of the fourth capacitor C6, the second end of the fourth capacitor C6 is grounded, and the fourth capacitor C6 is used to stabilize the voltage at the voltage output terminal of the power supply 10. The voltage input terminal (LV_VOUT) of the load 20 is connected to the first end of the fifth capacitor C7, the second end of the fifth capacitor C7 is grounded, and the fifth capacitor C7 is used to stabilize the voltage at the voltage input terminal of the load 20.

[0090] The power supply device further includes a fourth switch circuit 70, a first end of the fourth switch circuit 70 is connected to a first end of a fourth capacitor C6, a second end of the fourth switch circuit 70 is grounded, and a control end of the fourth switch circuit 70 is connected to the controller. In a specific application, the fourth switch circuit 70 includes a switch tube Q4, and the switch tube Q4 is a triode.

[0091] After determining that the first switch circuit 30 is normally turned on, and before outputting the second level signal to the first signal input terminal of the half-bridge drive circuit 50, the controller is also used to output a discharge control signal LV_DISCHARGE to the control terminal of the fourth switch circuit 70, so that the fourth switch circuit 70 is in a conducting state, so that the fourth capacitor C6 discharges energy, so as to further improve the accuracy of the self-test of the first switch circuit 30.

[0092] In this embodiment, the first switch circuit includes NMOS tubes connected in series back to back, which have the functions of preventing current backflow, battery reverse polarity protection and output cut-off. In the vehicle scenario, when the polarity of the low-voltage battery is reversed, the internal fault of the on-board DC / DC power supply or the load end is abnormal, the power circuit between the on-board DC / DC power supply and the low-voltage battery can be safely cut off, effectively protecting the on-board DC / DC power supply and preventing the vehicle's low-voltage power supply from dropping, and improving the fault isolation capability and product reliability of the on-board DC\DC power supply product at a relatively low cost. In addition, the NMOS tube solution has the significant advantages of low material cost and easy device selection.

[0093] In this embodiment, the charge pump principle of a simple half-bridge drive circuit and a charge pump circuit is combined to realize driving and powering the NMOS tube in the first switch circuit, which is simple to implement and low in cost, does not require additional isolated drive power supply, and does not need to be powered from the power circuit, which is conducive to the simplified design of the circuit and the improvement of power density. In addition, the power supply device also has a self-test function, which can test the functional effectiveness and integrity of the first switch circuit when powered on, to avoid the first switch circuit failing to operate normally when the vehicle-mounted DC\DC power supply is running, thereby causing a serious fault of loss of low-voltage power supply for the entire vehicle.

[0094] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A power supply device, characterized in that: The power supply device comprises: Power supply and load; A first switch circuit, wherein the first switch circuit includes a preset number of switch tubes, and the preset number of switch tubes are connected between the power supply and the load; An enabling control unit, the enabling control unit being used to output an enabling control signal; A driving unit, the driving unit comprising a half-bridge driving circuit and a charge pump circuit, wherein a first signal input terminal of the half-bridge driving circuit is connected to a signal output terminal of the enabling control unit, a floating power supply terminal of the half-bridge driving circuit is connected to the charge pump circuit, a first driving output terminal of the half-bridge driving circuit is connected to a gate of each of the switching tubes, and a floating ground terminal of the half-bridge driving circuit is connected to a source of each of the switching tubes; Wherein, when the enable control signal is a first level signal, the charge pump circuit is used to provide a floating power supply voltage for the floating power supply terminal, the first drive output terminal is configured to output a first drive voltage, and the voltage difference between the first drive voltage and the floating ground terminal is greater than the threshold voltage of each of the switch tubes, so that the first switch circuit is turned on; When the enable control signal is a second level signal, the first drive output terminal is configured to output a second drive voltage, and the voltage difference between the second drive voltage and the floating ground terminal is smaller than the threshold voltage of each of the switch tubes, so that the first switch circuit is turned off.

2. The power supply device according to claim 1, characterized in that: The charge pump circuit includes a charge and discharge circuit, a first power supply, a first diode, a second diode, a third diode, a first capacitor, a second capacitor and a first resistor; The voltage output terminal of the charge-discharge circuit is connected to the second signal input terminal of the half-bridge drive circuit, and the charge-discharge circuit is used for alternately charging and discharging, and alternately providing a charging voltage and a discharging voltage to the second signal input terminal of the half-bridge drive circuit; The first power supply is connected to the power supply terminal of the half-bridge driving circuit and the anode of the first diode, the cathode of the first diode is connected to the first end of the first capacitor, the floating power supply terminal and the cathode of the second diode, the anode of the second diode is connected to the cathode of the third diode and the first end of the second capacitor, the anode of the third diode is connected to the second end of the first capacitor and the floating ground terminal, the second end of the second capacitor is connected to the first end of the first resistor, and the second end of the first resistor is connected to the second driving output terminal of the half-bridge driving circuit; When the charge-discharge circuit is charged and the charging voltage meets the voltage condition, the second driving output terminal is configured to output a third level signal, and the second driving output terminal, the first resistor, the second capacitor, the second diode and the first capacitor form a first charging path to charge the first capacitor; When the charge and discharge circuit discharges and the discharge voltage does not meet the voltage condition, the second drive output end is configured to output a fourth level signal, the first power supply, the first diode, the first capacitor, the third diode, the second capacitor, the first resistor and the second drive output end form a second charging path to charge the first capacitor, and the level of the fourth level signal is lower than the level of the third level signal.

3. The power supply device according to claim 2, characterized in that: The charge and discharge circuit comprises a second resistor, a third resistor, a second switch circuit and a third capacitor, wherein a first end of the second resistor is used to be connected to a second power source, a second end of the second resistor is connected to a first end of the third resistor, a first end of the third capacitor and a second signal input end of the half-bridge drive circuit, a second end of the third resistor is connected to a first end of the second switch circuit, a second end of the second switch circuit and a second end of the third capacitor are both grounded, and a control end of the second switch circuit is used to alternately receive a fifth level signal and a sixth level signal; When the control end of the second switch circuit receives the fifth level signal, the second switch circuit is configured to be in an off state, and the second power supply charges the third capacitor to provide the charging voltage to the second signal input end of the half-bridge drive circuit; When the control end of the second switch circuit receives the sixth level signal, the second switch circuit is configured to be in an on state, the third capacitor discharges to provide the discharge voltage to the second signal input end of the half-bridge drive circuit, and the level of the sixth level signal is higher than the level of the fifth level signal.

4. The power supply device according to claim 3, characterized in that: The control end of the second switch circuit is connected to the second drive output end.

5. The power supply device according to claim 3, characterized in that: The charge and discharge circuit further includes a fourth diode, a cathode of the fourth diode is connected to the signal output end of the enable control unit, and an anode of the fourth diode is connected to the second end of the second resistor.

6. The power supply device according to claim 1, characterized in that: The first switch circuit includes a first switch tube and a second switch tube, the drain of the first switch tube is connected to the power supply, the source of the first switch tube is connected to the source of the second switch tube, and the drain of the second switch tube is connected to the load.

7. The power supply device according to claim 1, characterized in that: The enabling control unit comprises a sampling subunit and a fault detection subunit, wherein a sampling input end of the sampling subunit is connected to a power supply line between the power supply and the load, an input end of the fault detection subunit is connected to a signal output end of the sampling subunit, and the fault detection subunit is used to perform fault detection using sampling data output by the sampling subunit and output the enabling control signal; Wherein, when the fault detection subunit does not detect a fault, the enable control signal is the first level signal, and when the fault detection subunit detects a fault, the enable control signal is the second level signal.

8. The power supply device according to claim 7, characterized in that: The sampling subunit includes at least one of a first voltage sampling circuit, a second voltage sampling circuit, a first current sampling circuit, and a second current sampling circuit. The first voltage sampling circuit is used to obtain a first voltage between the first switch circuit and the load, the second voltage sampling circuit is used to obtain a second voltage between the power supply and the first switch circuit, the first current sampling circuit is used to obtain a first current flowing into the load, and the second current sampling circuit is used to obtain a second current flowing out of the load.

9. The power supply device according to claim 8, characterized in that: The sampling subunit includes the first voltage sampling circuit, the first voltage sampling circuit includes a first voltage dividing resistor, a second voltage dividing resistor and a third switch circuit, the first end of the first voltage dividing resistor is connected to the sampling input end of the first voltage sampling circuit, the second end of the first voltage dividing resistor is connected to the second voltage dividing resistor and the sampling output end of the first voltage sampling circuit, and the third switch circuit is connected to the sampling path between the sampling input end of the first voltage sampling circuit and the sampling output end of the first voltage sampling circuit; Wherein, when the power supply is not in sleep mode, the third switch circuit is configured to be in an on state, and when the power supply is not in sleep mode, the third switch circuit is configured to be in an off state.

10. The power supply device according to claim 8, characterized in that: The fault detection subunit includes at least one comparison circuit, the detection signal input end of each comparison circuit is respectively connected to the corresponding sampling circuit output end, the reference signal input end of each comparison circuit is respectively connected to the corresponding reference voltage providing circuit, and the output end of each comparison circuit is connected.

11. The power supply device according to claim 1, characterized in that: The power supply device further comprises a controller, and the controller is connected to the first signal input terminal of the half-bridge driving circuit; Before the power supply works, the controller is used to output the first level signal to the first signal input terminal of the half-bridge drive circuit, obtain the second voltage between the power supply and the first switch circuit, and judge whether the first switch circuit is normally turned on based on whether the second voltage meets the first preset voltage condition; and the controller is also used to output the second level signal to the first signal input terminal of the half-bridge drive circuit after judging that the first switch circuit is normally turned on, and judge whether the first switch circuit is normally turned off based on whether the second voltage meets the second preset voltage condition.

12. The power supply device according to claim 11, characterized in that: The voltage output end of the power supply is connected to the first end of the fourth capacitor, and the second end of the fourth capacitor is grounded; the power supply device also includes a fourth switch circuit, the first end of the fourth switch circuit is connected to the first end of the fourth capacitor, the second end of the fourth switch circuit is grounded, and the control end of the fourth switch circuit is connected to the controller; After determining that the first switch circuit is normally turned on and before outputting the second level signal to the first signal input terminal of the half-bridge drive circuit, the controller is further used to output a discharge control signal to the control terminal of the fourth switch circuit to put the fourth switch circuit in a conducting state, so that the fourth capacitor discharges energy.

13. The power supply device according to claim 1, characterized in that: The power supply is a vehicle-mounted power converter, which is used to convert the output voltage of the power battery. The load is a vehicle-mounted storage battery or a vehicle-mounted electrical appliance.

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