Power supply circuits and power switching equipment

Abstract

The present application relates to a power supply circuit and a power switching device. The power supply circuit includes a low-voltage startup boost module, a switch module, and a saturation conduction control module. The switch module includes at least a MOS tube and a non-locking button. The input end of the low-voltage startup boost module is respectively connected to the low-voltage drive power supply and the non-locking button. The output end of the low-voltage startup boost module and the output end of the saturation conduction control module are both connected to the gate of the MOS tube. The drain of the MOS tube is connected to the low-voltage drive power supply, and the source of the MOS tube is connected to the input end of the saturation conduction control module. The saturation conduction control module is used to output a control voltage to the gate of the MOS tube when the power supply signal disappears, so as to control the MOS tube to maintain a saturated conduction state. The disappearance of the power supply signal is triggered by releasing the non-locking button. The control voltage is greater than the saturation conduction voltage of the MOS tube. This can reduce the driving loss of the MOS tube when it is turned on.

Description

Technical Field

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

[0002] In the design of a switching power supply system for power electronic equipment, a switching circuit including a Metal-Oxide-Semiconductor Field-Effect Transistor (MOS) is usually set between the power supply and the auxiliary power supply. By controlling the on and off of the MOS tube, the switching between the two power supplies can be achieved.

[0003] In the related art, a fixed high-voltage driving power supply is mainly connected to a switch module including a MOS tube, the high-voltage driving power supply drives the MOS tube to conduct, and after the MOS tube is conducted, the MOS tube is maintained in a saturated conduction state.

[0004] However, the solutions of the related art are not applicable to low-voltage driving power supplies, and the driving loss is large when the MOS tube is turned on. Summary of the Invention

[0005] Based on this, it is necessary to provide a power supply circuit and a power switching device to address the above technical problems, which can be applicable to low-voltage driving power supplies and can reduce the driving loss when the MOS tube is turned on.

[0006] In a first aspect, the present application provides a power supply circuit, which includes a low-voltage startup boost module, a switch module, and a saturation conduction control module. The switch module includes at least a MOS transistor and a non-locking button. The input end of the low-voltage startup boost module is respectively connected to a low-voltage drive power supply and a non-locking button. The output end of the low-voltage startup boost module and the output end of the saturation conduction control module are both connected to the gate of the MOS transistor. The drain of the MOS transistor is connected to the low-voltage drive power supply, and the source of the MOS transistor is connected to the input end of the saturation conduction control module.

[0007] The low-voltage startup boost module is used to input the target voltage obtained by voltage conversion of the driving voltage of the low-voltage driving power supply to the gate of the MOS tube when receiving the power supply signal, so as to control the MOS tube to switch from the off state to the on state; the power supply signal is triggered by pressing the non-locking button; the target voltage is greater than the turn-on voltage of the MOS tube;

[0008] The saturation conduction control module is used to output a control voltage to the gate of the MOS tube when the power supply signal disappears, so as to control the MOS tube to maintain the saturation conduction state; the disappearance of the power supply signal is triggered by releasing the non-locking button; the control voltage is greater than the saturation conduction voltage of the MOS tube, and the saturation conduction voltage of the MOS tube is less than the turn-on voltage of the MOS tube.

[0009] In one embodiment, the saturation conduction control module includes: a voltage maintaining boost unit, a voltage stabilizing unit, and a control unit, wherein the input end of the voltage maintaining boost unit is respectively connected to the source of the MOS transistor, the gate of the MOS transistor, and the output end of the control unit, the output end of the voltage maintaining boost unit is respectively connected to the gate of the MOS transistor and the input end of the voltage stabilizing unit, and the output end of the voltage stabilizing unit is connected to the first input end of the control unit;

[0010] The boost unit is used to convert the driving voltage of the low-voltage driving power supply to obtain a control voltage, and output the control voltage to the gate of the MOS tube and the voltage stabilizing unit;

[0011] A voltage stabilizing unit, configured to convert the control voltage to obtain a power supply voltage for the control unit and send the power supply voltage to the control unit;

[0012] The control unit is used to supply power through the power supply voltage and output a first control signal through the output end; the first control signal is used to control the boost unit to be in a working state when the unlocked key is in an unlocked state.

[0013] In one embodiment, the switch module further includes a first switch unit, the second input terminal of the control unit is connected to the unlocking button via the first switch unit, and the first switch unit is connected to the output terminal of the voltage stabilizing unit;

[0014] The control unit is further configured to output a second control signal through the output terminal when the trigger signal is detected again at the second input terminal; the second control signal is configured to control the boost unit to be kept in the closed state.

[0015] In one embodiment, the first switch unit includes a first switch tube, a resistor 1, a resistor 2, and a first diode. The cathode of the first diode is connected to the unlocking button, the anode of the first diode is connected to the base of the first switch tube and the first end of the resistor 1, respectively. The emitter of the first switch tube is connected to the first end of the resistor 2 and the second input end of the control unit, respectively. The second end of the resistor 1 and the second end of the resistor 2 are both connected to the output end of the voltage stabilizing unit.

[0016] When the unlocking button is in the unlocked state, the first switch is in the off state; when the unlocking button is in the locked state again, the first switch is in the on state.

[0017] In one embodiment, the switch module further includes a second switch unit, wherein a first end of the second switch unit is connected to the unlocking button, a second end of the second switch unit is connected to the output end of the low-voltage startup boost module, and a third end of the second switch unit is connected to the gate of the MOS transistor;

[0018] When the unlocking key is in the locked state, the second switch unit is in the on state; when the unlocking key is in the unlocked state, the second switch unit is in the off state.

[0019] In one embodiment, the second switch unit includes: resistor three, resistor four and a second switch tube, the base of the second switch tube is connected to the unlocking button through resistor three, the emitter of the second switch tube and the first end of resistor four are both connected to the output end of the low-voltage startup boost module, and the collector of the second switch tube is connected to the gate of the MOS tube.

[0020] In one embodiment, the switch module further includes a second diode, a third diode, a resistor five, a resistor six, and a resistor seven, the anode of the second diode being connected to the output end of the second switch unit, the cathode of the second diode being connected to the first end of the resistor five, the anode of the third diode being connected to the output end of the saturation conduction control module, the cathode of the third diode being connected to the first end of the resistor six, the second end of the resistor five being respectively connected to the first end of the resistor seven and the gate of the MOS tube, and the second end of the resistor six being respectively connected to the first end of the resistor seven and the gate of the MOS tube, and the second end of the resistor seven being grounded.

[0021] In one embodiment, the low-voltage starting boost module includes multiple starting boost units, the input end of the first starting boost unit is connected to the low-voltage driving power supply, the starting boost units are connected in series, the output end of the last starting boost unit is connected to the switch module, and each starting boost unit is connected to a non-locking button.

[0022] In one embodiment, any one of the startup boost units includes: a fourth diode, a resistor eight, a resistor nine, a resistor ten, a resistor eleven, a third switch tube and a charging capacitor, wherein the anode of the fourth diode, the emitter of the third switch tube, and the first end of the resistor nine are all connected to the low-voltage driving power supply, the cathode of the fourth diode is connected to the first end of the resistor eight, the second end of the resistor eight is respectively connected to the first end of the charging capacitor and the switch module, the second end of the charging capacitor is respectively connected to the collector of the third switch tube and the first end of the resistor ten, the second end of the resistor nine and the base of the third switch tube are respectively connected to the first end of the resistor eleven, the second end of the resistor eleven is connected to the unlocking button, and the second end of the resistor ten is grounded;

[0023] When the unlocking key is in the locked state, the voltage at the common terminal of the second terminal of the resistor 8 and the first terminal of the charging capacitor increases to the target voltage.

[0024] In a second aspect, the present application further provides a power switching device, which includes the power supply circuit of any one of the above-mentioned first aspects.

[0025] The above-mentioned power supply circuit and power switching device, the power supply circuit includes a low-voltage startup boost module, a switch module and a saturation conduction control module, the switch module includes at least a MOS tube and a non-locking button, the input end of the low-voltage startup boost module is respectively connected to the low-voltage drive power supply and the non-locking button, the output end of the low-voltage startup boost module and the output end of the saturation conduction control module are both connected to the gate of the MOS tube, the drain of the MOS tube is connected to the low-voltage drive power supply, and the source of the MOS tube is connected to the input end of the saturation conduction control module; the low-voltage startup boost module is used to, when receiving a power supply signal, supply a voltage to the MOS tube. The gate input converts the driving voltage of the low-voltage driving power supply into a target voltage to control the MOS tube to switch from the off state to the on state; the power supply signal is triggered by pressing the unlock button; the target voltage is greater than the turn-on voltage of the MOS tube; the saturation conduction control module is used to output a control voltage to the gate of the MOS tube when the power supply signal disappears to control the MOS tube to maintain the saturated conduction state; the disappearance of the power supply signal is triggered by releasing the unlock button; the control voltage is greater than the saturation conduction voltage of the MOS tube, and the saturation conduction voltage of the MOS tube is less than the turn-on voltage of the MOS tube. The power supply circuit is provided with a low-voltage startup boost module between the low-voltage driving power supply and the MOS tube. When the user presses the unlock button, the driving voltage of the low-voltage driving power supply can be pulled up to the target voltage. The MOS tube is turned on under the drive of the target voltage, making the power supply circuit suitable for the low-voltage driving power supply. In addition, the power supply circuit is also provided with a saturation conduction control module. When the user releases the unlock button, the saturation conduction control module inputs a control voltage suitable for the saturated conduction state to the gate of the MOS tube, thereby reducing the driving loss when the MOS tube is turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 is a first circuit schematic diagram of a power supply circuit in one embodiment;

[0028] Figure 2 is a second circuit schematic diagram of a power supply circuit in one embodiment;

[0029] Figure 3FIG. 4 is a third circuit schematic diagram of a power supply circuit in one embodiment.

[0030] Description of reference numerals:

[0031] 10: Power supply circuit; 11: Low-voltage start-up boost module; 12: Switch module; 121: First switch unit; 122: Second switch unit; 13: Saturation conduction control module; 131: Maintaining boost unit; 132: Voltage stabilization unit; 133: Control unit; BAT: Low-voltage drive power supply. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0033] Before introducing the technical solution of the present application in detail, the technical solution of the present application is first introduced in detail.

[0034] In the design of switching power supply systems for power electronic equipment, a switching circuit is usually designed between the power supply and the auxiliary power supply. By controlling the on and off of the switching circuit, the auxiliary power supply system can be controlled, switching between the two power supplies is achieved, and thus the entire power electronic equipment can be controlled. MOS tubes can be used in switching circuits due to their excellent switching characteristics.

[0035] Taking a MOS transistor as an example, to reduce the conduction loss of the MOS transistor, it is generally necessary to ensure that the driving voltage after the MOS transistor is turned on is higher than its saturation conduction voltage. To reduce the switching loss of the MOS transistor and enhance its resistance to transient pulse currents during switching, it is generally necessary to increase the switching speed of the MOS transistor. To increase the switching speed of the MOS transistor, reduce its switching loss, and enhance its resistance to transient pulse currents, it is generally necessary to design a higher driving voltage for the MOS transistor. However, after the MOS transistor is turned on, the driving voltage only needs to be higher than the saturation conduction voltage of the MOS transistor to maintain the saturated conduction state of the MOS transistor. If the driving voltage is too high at this time, the driving loss of the MOS transistor during saturation conduction will increase.

[0036] In the related art, a fixed high-voltage drive power supply is primarily connected to a switch module including a MOS transistor. The high-voltage drive power supply drives the MOS transistor to conduct, and after the MOS transistor is turned on, the MOS transistor is maintained in a saturated conduction state. The related art solutions have the following main disadvantages: First, in power electronic devices with a high power supply voltage (the power supply voltage is higher than the saturation operating voltage of the MOS transistor, such as power supply with three or more battery cells in series), it is easy to provide a high drive voltage to the MOS transistor to achieve high-speed MOS switching. However, in power electronic devices with a very low power supply voltage (such as power supply with a single battery cell in series), the low input power supply voltage results in slow MOS transistor switching speeds, high switching losses, and even failure to drive the MOS transistor, causing the auxiliary power system to fail to start. Second, with a fixed high-voltage drive power supply design, once the MOS transistor is turned on, its drive voltage remains high, which increases the drive losses when the MOS transistor is in saturation conduction.

[0037] To address the above issues, the present application provides a power supply circuit and a power switching device that are applicable to low-voltage drive power supplies and can reduce drive losses when MOS transistors are turned on. The technical solution of the present application is described in detail below.

[0038] In one embodiment, Figure 1 As shown, a power supply circuit 10 is provided. The power supply circuit 10 includes a low-voltage startup boost module 11, a switch module 12, and a saturation conduction control module 13. The switch module 12 includes at least a MOS transistor and a non-locking button SW. The input end of the low-voltage startup boost module 11 is respectively connected to the low-voltage driving power supply BAT and the non-locking button SW. The output end of the low-voltage startup boost module 11 and the output end of the saturation conduction control module 13 are both connected to the gate of the MOS transistor. The drain of the MOS transistor is connected to the low-voltage driving power supply BAT. The source of the MOS transistor is connected to the input end of the saturation conduction control module 13.

[0039] The low-voltage startup boost module 11 is used to input a target voltage obtained by voltage conversion of the driving voltage of the low-voltage driving power supply BAT to the gate of the MOS tube when receiving a power supply signal, so as to control the MOS tube to switch from the off state to the on state; the power supply signal is triggered by pressing the unlocking button SW; the target voltage is greater than the turn-on voltage of the MOS tube;

[0040] The saturation conduction control module 13 is used to output a control voltage to the gate of the MOS tube when the power supply signal disappears, so as to control the MOS tube to maintain a saturated conduction state; the disappearance of the power supply signal is triggered by releasing the unlocking button SW; the control voltage is greater than the saturation conduction voltage of the MOS tube, and the saturation conduction voltage of the MOS tube is less than the turn-on voltage of the MOS tube.

[0041] In the embodiment of the present application, the MOS tube represents a switch arranged between the power supply and the auxiliary power supply, and the power supply circuit 10 mainly provides a suitable voltage for the MOS tube when the MOS tube needs to be turned on. When the MOS tube needs to be turned on, the MOS tube can be powered by the power supply circuit 10. At this time, the user can press the non-locking button SW to turn on the MOS tube and maintain it in a saturated conduction state. When the MOS tube is not needed to be turned on, the user can also press the non-locking button SW again to turn off the MOS tube. It should be noted that the non-locking button SW can be understood as a switch. When the user presses it, the switch is closed, and when released, the switch is automatically disconnected. For example, the non-locking button SW can be a touch button, a membrane button, a wave button, or the like.

[0042] The input end of the low-voltage startup boost module 11 in the power supply circuit 10 is connected to the low-voltage driving power supply BAT and the unlocking button SW respectively. The low-voltage startup boost module 11 can receive the driving voltage from the low-voltage driving power supply BAT. When the unlocking button SW is pressed, it can obtain a trigger signal, perform voltage conversion on the driving voltage, and obtain a target voltage. Its output end is connected to the gate of the MOS tube, and can transmit the target voltage to the gate of the MOS tube, so that the gate voltage of the MOS tube is greater than the saturation conduction voltage threshold, and the MOS tube is turned on, that is, the MOS tube is controlled to switch from the off state to the on state. Since the driving voltage of the low-voltage driving power supply BAT is small and insufficient to turn on the MOS tube, the essence of the low-voltage startup boost module 11 is to increase the driving voltage of the low-voltage driving power supply BAT to the target voltage, and turn on the MOS tube through the target voltage.

[0043] The output of the saturation conduction control module 13 is also connected to the gate of the MOS transistor. When the user releases the unlocking button SW, it outputs a control voltage to the gate of the MOS transistor to maintain the MOS transistor in a saturated conduction state. The input of the saturation conduction control module 13 is connected to the source of the MOS transistor. Thus, when the MOS transistor is on, the saturation conduction control module 13 remains in operation. In other words, the primary function of the saturation conduction control module 13 is to output a control voltage to the gate of the MOS transistor to maintain the MOS transistor in a saturated conduction state. The control voltage is greater than the saturation conduction voltage of the MOS transistor, and the saturation conduction voltage of the MOS transistor is less than the turn-on voltage of the MOS transistor. That is, the control voltage is less than the turn-on voltage. When the MOS transistor is in the on state, it is maintained at a control voltage that is just sufficient to maintain the saturated conduction state. This reduces the driving loss when the MOS transistor is on. It is understood that the MOS transistor can be either an N-channel MOS transistor or a P-channel MOS transistor.

[0044] The power supply circuit 10 includes a low-voltage startup boost module 11, a switch module 12 and a saturation conduction control module 13. The switch module 12 includes at least a MOS transistor and a non-locking button SW. The input end of the low-voltage startup boost module 11 is connected to the low-voltage driving power supply BAT and the non-locking button SW respectively. The output end of the low-voltage startup boost module 11 and the output end of the saturation conduction control module 13 are both connected to the gate of the MOS transistor. The drain of the MOS transistor is connected to the low-voltage driving power supply BAT, and the source of the MOS transistor is connected to the input end of the saturation conduction control module 13. The low-voltage startup boost module 11 is used to, when receiving a power supply signal, supply a power supply to the MOS transistor. The gate input of the OS transistor converts the driving voltage of the low-voltage driving power supply BAT to obtain a target voltage to control the MOS transistor to switch from the off state to the on state; the power supply signal is triggered by pressing the unlocking button SW; the target voltage is greater than the turn-on voltage of the MOS transistor; the saturation conduction control module 13 is used to output a control voltage to the gate of the MOS transistor when the power supply signal disappears to control the MOS transistor to maintain the saturated conduction state; the disappearance of the power supply signal is triggered by releasing the unlocking button SW; the control voltage is greater than the saturation conduction voltage of the MOS transistor, and the saturation conduction voltage of the MOS transistor is less than the turn-on voltage of the MOS transistor. The power supply circuit 10 is provided with a low-voltage startup boost module 11 between the low-voltage driving power supply BAT and the MOS transistor. When the user presses the unlocking button SW, the driving voltage of the low-voltage driving power supply BAT can be pulled up to the target voltage, and the MOS transistor is turned on under the drive of the target voltage, making the power supply circuit 10 suitable for the low-voltage driving power supply BAT. In addition, the power supply circuit 10 is also provided with a saturation conduction control module 13. When the user releases the unlocking button SW, the saturation conduction control module 13 inputs a control voltage suitable for the saturation conduction state to the gate of the MOS tube, thereby reducing the driving loss of the MOS tube when it is turned on.

[0045] The above embodiment mainly involves three parts: a low-voltage startup boost module 11 , a switch module 12 and a saturation conduction control module 13 . These three parts will be described in detail below.

[0046] First, the specific contents of the saturation conduction control module 13 are introduced through an embodiment. Figure 2 As shown, the saturation conduction control module 13 includes: a voltage maintenance boost unit 131, a voltage stabilizing unit 132 and a control unit 133. The input end of the voltage maintenance boost unit 131 is respectively connected to the source of the MOS transistor, the gate of the MOS transistor, and the output end of the control unit 133. The output end of the voltage maintenance boost unit 131 is respectively connected to the gate of the MOS transistor and the input end of the voltage stabilizing unit 132. The output end of the voltage stabilizing unit 132 is connected to the first input end of the control unit 133.

[0047] The voltage boost unit 131 is used to convert the driving voltage of the low-voltage driving power supply BAT to obtain a control voltage, and output the control voltage to the gate of the MOS tube and the voltage stabilizing unit 132;

[0048] The voltage stabilizing unit 132 is used to convert the control voltage to obtain the supply voltage of the control unit 133 and send the supply voltage to the control unit 133;

[0049] The control unit 133 is used to supply power through the power supply voltage and output a first control signal through the output terminal; the first control signal is used to control the boost unit 131 to be in a working state when the unlocking key SW is in an unlocked state.

[0050] In the embodiment of the present application, the main function of the boost unit 131 is to provide a control voltage to maintain the MOS transistor in a saturated conduction state after the MOS transistor is turned on. The boost unit 131 can include a boost control integrated circuit chip U1 and other electronic components. Specifically, the input terminal VIN of the boost control integrated circuit chip U1 can be connected to the source of the MOS transistor, and the enable pin EN of the boost control integrated circuit chip U1 can be connected to the collector of the second switch Q2 via a fifth diode D5. At the same time, it can also be connected to the output terminal of the control unit 133 via a sixth diode D6.

[0051] The voltage output terminal Vo of the boost control integrated circuit chip U1 is connected to the input terminal VIN of the voltage stabilizing unit 132, and the output terminal Vo of the voltage stabilizing unit 132 is connected to the input terminal VCC of the control unit 133. It should be noted that the voltage stabilizing unit 132 can be a linear voltage regulator (LDO) circuit composed of the buck control integrated circuit chip U2. Its main purpose is to step down the control voltage output by the boost unit 131 to the supply voltage of the control unit 133. The control unit 133 can be a microcontroller unit (MCU).

[0052] It should be noted that the control voltage output by the boost unit 131 can be flexibly set based on the saturation conduction voltage of the MOS transistor, thereby reducing the driving loss of the MOS transistor in the conduction state.

[0053] The saturation conduction control module 13 includes: a voltage maintenance boost unit 131, a voltage stabilizing unit 132, and a control unit 133. The input end of the voltage maintenance boost unit 131 is respectively connected to the source of the MOS transistor, the gate of the MOS transistor, and the output end of the control unit 133. The output end of the voltage maintenance boost unit 131 is respectively connected to the gate of the MOS transistor and the input end of the voltage stabilizing unit 132. The output end of the voltage stabilizing unit 132 is connected to the first input end of the control unit 133. The voltage maintenance boost unit 131 is used to perform voltage conversion on the driving voltage of the low-voltage driving power supply BAT to obtain a control voltage, and output the control voltage to the gate of the MOS transistor and the voltage stabilizing unit 132. The voltage stabilizing unit 132 is used to perform voltage conversion on the control voltage to obtain a supply voltage for the control unit 133, and send the supply voltage to the control unit 133. The control unit 133 is used to supply power using the supply voltage and output a first control signal through its output end. The first control signal is used to control the voltage maintenance boost unit 131 to be in an operating state when the unlocking key SW is in the unlocking state. By maintaining the coordination among the boost unit 131 , the voltage stabilizing unit 132 and the control unit 133 , it is possible to ensure that the MOS tube is always in a saturated conduction state after being turned on, thereby reducing the power consumption of the MOS tube in the conduction state.

[0054] Next, the switch module 12 in the above embodiment is described in detail. Figure 2 As shown, the switch module 12 further includes a first switch unit 121, the second input end of the control unit 133 is connected to the unlocking key SW via the first switch unit 121, and the first switch unit 121 is connected to the output end of the voltage stabilizing unit 132;

[0055] The control unit 133 is further configured to output a second control signal through the output terminal when the trigger signal is detected again at the second input terminal; the second control signal is configured to control the boost unit 131 to be kept in the off state.

[0056] The trigger signal may be triggered by the user pressing the unlock button again, and the trigger signal is a rising edge signal. That is, after the control unit is powered on, when a rising edge trigger signal is detected, the boost unit 131 may be controlled to be kept in the off state.

[0057] Specifically, such as Figure 3As shown, the first switch unit 121 includes a first switch tube Q1, a resistor R1, a resistor R2, and a first diode D1. The cathode of the first diode D1 is connected to the unlocking button SW, the anode of the first diode D1 is connected to the base of the first switch tube Q1 and the first end of the resistor R1, respectively. The emitter of the first switch tube Q1 is connected to the first end of the resistor R2 and the second input end of the control unit 133, respectively. The second end of the resistor R1 and the second end of the resistor R2 are both connected to the output end of the voltage stabilizing unit 132.

[0058] When the unlocking button SW is in the unlocked state, the first switch tube Q1 is in the off state; when the unlocking button SW is in the locked state again, the first switch tube Q1 is in the on state.

[0059] In the embodiment of the present application, when the user presses the unlock button SW, the unlock button SW is closed, and the base voltage of the first switch tube Q1 is pulled down after passing through the first diode D1 and the unlock button SW, so that the base voltage is lower than the conduction threshold voltage of the first switch tube Q1, and the first switch tube Q1 is turned on.

[0060] When the user releases the unlocking button SW, the output terminal of the voltage stabilizing unit 132 is connected to the second end of resistor 1 R1 and the second end of resistor 2 R2. Therefore, the supply voltage output by the output terminal of the voltage stabilizing unit 132 passes through resistor 1 R1, raising the base voltage of the first switch Q1. This voltage increases the base voltage above the conduction threshold voltage, and the first switch Q1 remains in the off state. At this point, the control unit is in the power-on state.

[0061] When the user presses the unlock button SW again, the first switch tube Q1 is turned on, and the shutdown command signal at the second input terminal of the control unit 133 is pulled low. At this time, the control unit 133 can detect the low-level shutdown command signal.

[0062] When the user releases the unlocking button SW again, the first switch Q1 turns off, and the shutdown command signal at the second input terminal of the control unit 133 goes high, detecting a trigger signal of a rising edge signal. At this point, the control unit 133 can output a second control signal to the boost unit 131 via its output terminal, thereby controlling the boost unit 131 to remain in the off state.

[0063] The switch module 12 further includes a first switch unit 121. A second input terminal of the control unit 133 is connected to the unlocking button SW via the first switch unit 121, and the first switch unit 121 is connected to the output terminal of the voltage stabilizing unit 132. The control unit 133 is further configured to output a second control signal via its output terminal upon detecting a trigger signal at the second input terminal again. The second control signal is used to control the boost unit 131 to remain in the off state. By providing the first switch unit 121 between the unlocking button SW and the control unit 133, the control unit 133 can trigger different types of signals based on the on and off states of the first switch unit 121, thereby accurately controlling the operation of the boost unit 131.

[0064] On the basis of the above embodiment, continue to refer to Figure 2 As shown, the switch module 12 further includes a second switch unit 122, a first end of the second switch unit 122 is connected to the unlocking button SW, a second end of the second switch unit 122 is connected to the output end of the low-voltage startup boost module 11, and a third end of the second switch unit 122 is connected to the gate of the MOS tube;

[0065] When the unlocking key SW is in the locked state, the second switch unit 122 is in the on state; when the unlocking key SW is in the unlocked state, the second switch unit 122 is in the off state.

[0066] For details, see Figure 3 As shown, the second switch unit 122 includes: a third resistor R3, a fourth resistor R4, and a second switch tube Q2. The base of the second switch tube Q2 is connected to the unlocking button SW via the third resistor R3. The emitter of the second switch tube Q2 and the first end of the fourth resistor R4 are both connected to the output end of the low-voltage startup boost module 11. The collector of the second switch tube Q2 is connected to the gate of the MOS tube.

[0067] The switch module further includes a second diode D2, a third diode D3, a resistor R5, a resistor R6, and a resistor R7. The anode of the second diode D2 is connected to the output end of the second switch unit 122, the cathode of the second diode D2 is connected to the first end of the resistor R5, the anode of the third diode D3 is connected to the output end of the saturation conduction control module 13, the cathode of the third diode D3 is connected to the first end of the resistor R6, the second end of the resistor R5 is respectively connected to the first end of the resistor R7 and the gate of the MOS transistor, and the second end of the resistor R6 is respectively connected to the first end of the resistor R7 and the gate of the MOS transistor. The second end of the resistor R7 is grounded.

[0068] In the embodiment of the present application, when a user presses the unlocking button SW, the unlocking button SW closes, and resistor 3 R3 is short-circuited to ground through the unlocking button SW, thereby lowering the base voltage of the second switch Q2. The output voltage of the low-voltage startup boost module 11 (the voltage common to the second end of resistor 8 R8 and the first end of the charging capacitor C) is divided by resistors 4 R4 and 3 R3, causing the base voltage to be less than the conduction threshold voltage of the second switch Q2, turning on the second switch Q2. After the second switch Q2 is turned on, the output voltage of the low-voltage startup boost module 11 passes through the second switch Q2, the second diode D2, the fifth resistor R5, and the seventh resistor R7, raising the gate voltage of the MOS transistor so that the gate voltage exceeds the saturation conduction voltage threshold of the MOS transistor, allowing the MOS transistor to quickly turn on, thereby reducing turn-on losses.

[0069] When the user releases the unlocking button SW, the output voltage of the low-voltage startup boost module 11 pulls up the voltage across the resistor R3, thereby raising the base voltage of the second switch tube Q2, so that the base voltage is higher than the conduction threshold voltage of the second switch tube Q2, and the second switch tube Q2 is turned off.

[0070] When the user presses the unlock button SW again, the second switch tube Q2 is turned on. When the user releases the unlock button SW again, the second switch tube Q2 is turned off.

[0071] The switch module 12 further includes a second switch unit 122. A first end of the second switch unit 122 is connected to the unlocking button SW, a second end of the second switch unit 122 is connected to the output end of the low-voltage startup boost module 11, and a third end of the second switch unit 122 is connected to the gate of the MOS transistor. When the unlocking button SW is locked, the second switch unit 122 is in the on state; when the unlocking button SW is unlocked, the second switch unit 122 is in the off state. By providing the second switch unit 122 between the low-voltage startup boost module 11 and the MOS transistor, and by pressing or releasing the unlocking button SW, the on and off state of the second switch unit 122 can be accurately controlled, thereby accurately controlling whether the MOS transistor is turned on and turned on.

[0072] Finally, the specific contents of the low-voltage starting boost module 11 are introduced through an embodiment. Figure 2 As shown, the low-voltage starting boost module 11 includes multiple starting boost units (see starting boost unit 1, starting boost unit 2, ..., starting boost unit N in the figure), the input end of the first starting boost unit is connected to the low-voltage driving power supply BAT, the starting boost units are connected in series, and the output end of the last starting boost unit is connected to the switch module 12, and each starting boost unit is connected to the non-locking button SW.

[0073] In the embodiment of the present application, the low-voltage startup boost module 11 can boost the voltage using multiple internal startup boost units. The number of startup boost units required varies for different MOS transistors and low-voltage drive power supplies BAT. In other words, during the design process, the low-voltage startup boost module 11 can determine a target voltage based on the turn-on voltage of the MOS transistor. The voltage difference between the drive voltage of the low-voltage drive power supply BAT and the target voltage is then calculated, and the number of startup boost units is determined based on this voltage difference.

[0074] In one embodiment, see Figure 3 As shown, any one of the startup boost units includes: a fourth diode D4, a resistor R8, a resistor R9, a resistor R10, a resistor R11, a third switch tube Q3, and a charging capacitor C. The anode of the fourth diode D4, the emitter of the third switch tube Q3, and the first end of the resistor R9 are all connected to the low-voltage driving power supply BAT. The cathode of the fourth diode D4 is connected to the first end of the resistor R8. The second end of the resistor R8 is respectively connected to the first end of the charging capacitor C and the switch module 12. The second end of the charging capacitor C is respectively connected to the collector of the third switch tube Q3 and the first end of the resistor R10. The second end of the resistor R9 and the base of the third switch tube Q3 are respectively connected to the first end of the resistor R11. The second end of the resistor R11 is connected to the unlocking button SW. The second end of the resistor R10 is grounded.

[0075] When the unlocking key SW is in the locked state, the voltage at the common terminal of the second end of the resistor R8 and the first end of the charging capacitor C increases to the target voltage.

[0076] It should be noted that the anode of the fourth diode D4, the emitter of the third switch tube Q3, and the first end of the resistor R9 in the first startup boost unit are all connected to the low-voltage drive power supply BAT, and the anode of the fourth diode D4, the emitter of the third switch tube Q3, and the first end of the resistor R9 in the second startup boost unit are all connected to the common end of the second end of the resistor R8 in the first startup boost unit and the first end of the charging capacitor C. The startup boost units are connected in the above manner, and the common end of the second end of the resistor R8 and the first end of the charging capacitor C in the last startup boost unit is connected to the switch module 12.

[0077] When the user does not press the unlock button SW, the power supply circuit 10 is not started, and the driving voltage of the low-voltage driving power supply BAT is charged to the charging capacitor C through the fourth diode D4, the resistor eight R8 and the resistor ten R10, so that the voltage across the charging capacitor C is equal to the driving voltage of the low-voltage driving power supply BAT.

[0078] When the user presses the unlock button SW for the first time, the unlock button SW closes, and resistor R11 is short-circuited to ground through the unlock button SW. Simultaneously, the driving voltage of the low-voltage driving power supply BAT is divided and limited by resistors R9 and R11, lowering the base voltage of the third switch Q3 to below the conduction threshold voltage of the third switch Q3, turning the third switch Q3 on. After the third switch Q3 is turned on, the driving voltage of the low-voltage driving power supply BAT is directly applied to the common terminal of the second end of resistor R8 and the first end of charging capacitor C through the third switch Q3. At this time, the voltage at the common terminal of resistor R8 and charging capacitor C is instantly raised to twice the driving voltage. Assuming that the low-voltage startup boost module 11 includes only one startup boost unit, the voltage at the common terminal of resistor R8 and charging capacitor C is the target voltage input to the gate of the MOS transistor.

[0079] When the user releases the unlock button SW after pressing it for the first time, the unlock button SW is automatically disconnected. The driving voltage of the low-voltage driving power supply BAT passes through the resistor R9 to increase the base voltage of the third switch tube Q3, making its base voltage higher than its conduction threshold voltage, and the third switch tube Q3 is turned off.

[0080] When the user presses the unlock button SW again, it closes, and the third switch Q3 turns on. When the user presses the unlock button SW again and then releases it, the unlock button SW automatically turns off. The drive voltage from the low-voltage drive power supply BAT passes through resistor R9, raising the base voltage of the third switch Q3 to above its conduction threshold voltage, turning the third switch Q3 off.

[0081] The low-voltage startup boost module 11 includes multiple startup boost units. The input of the first startup boost unit is connected to the low-voltage drive power supply BAT. The startup boost units are connected in series, and the output of the last startup boost unit is connected to the switch module 12. Each startup boost unit is also connected to the unlocking key SW. Based on the driving voltage of the low-voltage drive power supply BAT and the turn-on voltage of the MOS tube, the number of startup boost units in the low-voltage startup boost module 11 can be flexibly adjusted. Through the coordinated operation of multiple startup boost units, the driving voltage of the low-voltage drive power supply BAT can be converted to ensure the turn-on of the MOS tube.

[0082] Continue to see Figure 3 As shown, in order to further illustrate the principle of the power supply circuit 10, the low-voltage starting boost module 11 including a starting boost unit is taken as an example to illustrate the four stages of pressing, releasing, pressing again and releasing again the non-locking button SW.

[0083] To turn on the MOS transistor, the user presses the unlocking button SW, which closes and turns on the third switch Q3. The voltage at the common terminal (the second end of resistor R8 and the first end of charging capacitor C) increases to twice the drive voltage, i.e., the target voltage. The second switch Q2 turns on. The target voltage at the common terminal passes through the second switch Q2, the second diode D2, the fifth resistor R5, and the seventh resistor R7, raising the gate voltage of the MOS transistor, completing the rapid turn-on operation.

[0084] At the same time, the target voltage at the common terminal between the second end of resistor R8 and the first end of charging capacitor C passes through second switch Q2 and fifth diode D5, raising the potential of enable pin EN of boost control integrated circuit chip U1, and boost control integrated circuit chip U1 begins operation. After the MOS transistor is turned on, the drive voltage from low-voltage drive power supply BAT is supplied to boost control integrated circuit chip U1 through the MOS transistor, causing boost control integrated circuit chip U1 to output the control voltage.

[0085] On the one hand, the control voltage acts on the gate of the MOS transistor after passing through the third diode D3 and the sixth resistor R6. After the unlocking button SW is released, the MOS transistor is driven to maintain a saturated conduction state. On the other hand, the control voltage passes through the voltage regulator unit 132 and outputs a supply voltage to the control unit 133. At this point, the control unit 133 begins operation and outputs a first control signal. The first control signal acts on the enable pin EN of the boost control integrated circuit chip U1 through the sixth diode D6, ensuring that the boost control integrated circuit chip U1 can continue to operate normally and output the control voltage after the unlocking button SW is released. Furthermore, the supply voltage can control the first switch Q1 to remain in the off state.

[0086] When the user releases the unlocking button SW, the unlocking button SW is automatically disconnected, the second switch tube Q2 and the third switch tube Q3 are turned off, and the MOS tube continues to maintain a saturated conduction state under the action of the boost control integrated circuit chip U1. At this time, the turning-on action of the MOS tube is completed.

[0087] When the user presses the unlock button SW again, the first switch Q1 turns on, and the shutdown command signal at the second input terminal of the control unit 133 is pulled low. When the user releases the unlock button SW, the unlock button SW automatically turns off, the first switch Q1 turns off, and the shutdown command signal at the second input terminal of the control unit 133 is pulled high. The control unit 133 can then detect a rising edge trigger signal and output the second control signal through the output terminal. The second and third switches Q2 and Q3 turn off, and the enable pin EN of the boost control integrated circuit chip U1 is pulled low by resistor R12. The boost control integrated circuit chip U1 stops operating and stops outputting the control voltage. The gate voltage of the MOS transistor is pulled low by resistor R7, turning the MOS transistor off. At this point, the MOS transistor shutdown action is complete.

[0088] It is understandable that the first switch tube Q1 , the second switch tube Q2 and the third switch tube Q3 may be positive-negative-positive (PNP) transistors formed by two P-type semiconductors with an N-type semiconductor sandwiched between them.

[0089] In one embodiment, a power switching device is further provided. The power switching device includes the power supply circuit 10 in any one of the above embodiments.

[0090] It should be noted that the power switching device can be a separate switching device. By connecting the power switching device between the power supply and the auxiliary power supply, the switching between the power supply and the auxiliary power supply can be achieved.

[0091] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0092] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A power supply circuit, characterized in that: The power supply circuit includes a low-voltage startup boost module, a switch module and a saturation conduction control module. The switch module includes at least a MOS transistor and a non-locking button. The input end of the low-voltage startup boost module is respectively connected to the low-voltage driving power supply and the non-locking button. The output end of the low-voltage startup boost module and the output end of the saturation conduction control module are both connected to the gate of the MOS transistor. The drain of the MOS transistor is connected to the low-voltage driving power supply. The source of the MOS transistor is connected to the input end of the saturation conduction control module. The low-voltage startup boost module is configured to input a target voltage obtained by voltage conversion of the driving voltage of the low-voltage driving power supply to the gate of the MOS transistor upon receiving a power supply signal, so as to control the MOS transistor to switch from an off state to an on state; The power supply signal is triggered by pressing the unlock button; the target voltage is greater than the turn-on voltage of the MOS tube; The saturation conduction control module is configured to output a control voltage to the gate of the MOS transistor to control the MOS transistor to maintain a saturated conduction state when the power supply signal disappears; the disappearance of the power supply signal is triggered by releasing the non-locking button; the control voltage is greater than the saturation conduction voltage of the MOS transistor, and the saturation conduction voltage of the MOS transistor is less than the turn-on voltage of the MOS transistor; and the target voltage is greater than the control voltage.

2. The circuit according to claim 1, wherein: The saturation conduction control module includes: a voltage maintenance boost unit, a voltage stabilizing unit, and a control unit, wherein the input end of the voltage maintenance boost unit is respectively connected to the source of the MOS transistor, the gate of the MOS transistor, and the output end of the control unit, the output end of the voltage maintenance boost unit is respectively connected to the gate of the MOS transistor and the input end of the voltage stabilizing unit, and the output end of the voltage stabilizing unit is connected to the first input end of the control unit; The voltage maintenance boost unit is used to perform voltage conversion on the driving voltage of the low-voltage driving power supply to obtain a control voltage, and output the control voltage to the gate of the MOS tube and the voltage stabilizing unit; The voltage stabilizing unit is configured to perform voltage conversion on the control voltage to obtain a power supply voltage for the control unit, and send the power supply voltage to the control unit; The control unit is used to supply power through the power supply voltage and output a first control signal through the output end; the first control signal is used to control the boost unit to be in a working state when the unlocked key is in an unlocked state.

3. The circuit according to claim 2, characterized in that The switch module further includes a first switch unit, the second input end of the control unit is connected to the unlocking button via the first switch unit, and the first switch unit is connected to the output end of the voltage stabilizing unit; The control unit is further configured to output a second control signal through the output terminal when the trigger signal is detected again at the second input terminal; the second control signal is configured to control the boost unit to be kept in an off state.

4. The circuit according to claim 3, characterized in that The first switch unit includes a first switch tube, a resistor 1, a resistor 2, and a first diode. The cathode of the first diode is connected to the unlocking button, the anode of the first diode is connected to the base of the first switch tube and the first end of the resistor 1, respectively. The emitter of the first switch tube is connected to the first end of the resistor 2 and the second input end of the control unit, respectively. The second end of the resistor 1 and the second end of the resistor 2 are both connected to the output end of the voltage stabilizing unit. When the unlocking button is in the unlocked state, the first switch tube is in the off state; when the unlocking button is in the locked state again, the first switch tube is in the on state.

5. The circuit according to any one of claims 1 to 4, characterized in that: The switch module further includes a second switch unit, wherein a first end of the second switch unit is connected to the unlocking button, a second end of the second switch unit is connected to the output end of the low-voltage startup boost module, and a third end of the second switch unit is connected to the gate of the MOS transistor; When the unlocking button is in the locked state, the second switch unit is in the on state; when the unlocking button is in the unlocked state, the second switch unit is in the off state.

6. The circuit according to claim 5, characterized in that The second switch unit includes: resistor three, resistor four and a second switch tube. The base of the second switch tube is connected to the unlocking button through resistor three. The emitter of the second switch tube and the first end of resistor four are both connected to the output end of the low-voltage startup boost module. The collector of the second switch tube is connected to the gate of the MOS tube.

7. The circuit according to claim 5, characterized in that The switch module also includes a second diode, a third diode, a resistor five, a resistor six, and a resistor seven. The anode of the second diode is connected to the output end of the second switch unit, the cathode of the second diode is connected to the first end of the resistor five, the anode of the third diode is connected to the output end of the saturation conduction control module, the cathode of the third diode is connected to the first end of the resistor six, the second end of the resistor five is respectively connected to the first end of the resistor seven and the gate of the MOS tube, and the second end of the resistor six is ​​respectively connected to the first end of the resistor seven and the gate of the MOS tube, and the second end of the resistor seven is grounded.

8. The circuit according to any one of claims 1 to 4, characterized in that: The low-voltage starting boost module includes multiple starting boost units, the input end of the first starting boost unit is connected to the low-voltage driving power supply, each of the starting boost units is connected in series, the output end of the last starting boost unit is connected to the switch module, and each starting boost unit is connected to the non-locking button.

9. The circuit according to claim 8, characterized in that Any one of the startup boost units includes: a fourth diode, a resistor eight, a resistor nine, a resistor ten, a resistor eleven, a third switch tube and a charging capacitor, wherein the anode of the fourth diode, the emitter of the third switch tube and the first end of the resistor nine are all connected to the low-voltage driving power supply, the cathode of the fourth diode is connected to the first end of the resistor eight, the second end of the resistor eight is respectively connected to the first end of the charging capacitor and the switch module, the second end of the charging capacitor is respectively connected to the collector of the third switch tube and the first end of the resistor ten, the second end of the resistor nine and the base of the third switch tube are respectively connected to the first end of the resistor eleven, the second end of the resistor eleven is connected to the unlocking button, and the second end of the resistor ten is grounded; When the unlocking key is in the locked state, the voltage at the common end of the second end of the resistor 8 and the first end of the charging capacitor increases to the target voltage.

10. A power switching device, characterized in that: The power switching device includes the power supply circuit according to any one of claims 1 to 9.

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