Power supply turn-off circuit
By designing bidirectional switches, on-off drive circuits and energy discharge circuits in the motor power supply side circuit, the problem that existing circuits cannot quickly release energy is solved, and rapid shutdown under large currents is achieved, and the safety level is improved.
Patent Information
- Application Number
- CN202421134049.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-22
- Publication Date
- 2025-03-04
- Estimated Expiration
- 2034-05-22
AI Technical Summary
When the existing motor power supply side circuit faces high functional safety level and high reliability requirements, it cannot quickly release energy, resulting in slow shutdown speed of PMOS tubes and cannot meet the fast shutdown requirements under large currents, which poses a major safety hazard.
A power supply power supply shutdown circuit is designed, including a bidirectional switch, an on-off drive circuit and an energy discharge circuit. The energy discharge circuit is connected between the output end of the bidirectional switch and the drive end for grounding, so that the energy discharges to the ground when the bidirectional switch is turned off, achieving rapid shutdown.
Through the design of the energy discharge circuit, the two-way switch is quickly turned off in the application scenario of high-current power supply, which improves the safety level of the circuit and avoids safety hazards caused by slow shutdown speed.
Smart Images
Figure CN222563794U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of integrated power supply, in particular to a power supply shutoff circuit. Background Art
[0002] In traditional controller circuit design, the power supply of the motor and the solenoid valve is always powered. This power supply method is very mature in the industry. Combined with other R&D requirements of vehicle manufacturers for controllers (such as current size, ISO16750 and other specifications), developers generally choose Figure 1 Specifically, Figure 1 It is a motor power supply side circuit in the prior art, including an NMOS tube (T0) and a charge pump 21 for controlling the on-off of the NMOS tube. The source of the NMOS tube is connected to the vehicle power supply Vbat, and the drain leads to the power bus 40, and the power bus 40 is connected to the load. Figure 1 The circuit architecture can meet the needs of traditional controllers such as large current and power reverse protection, but it cannot achieve the requirements of high functional safety level and high reliability. When the power bus short-circuits to the ground or a cascade failure occurs on the motor drive side, this circuit architecture will not only damage the controller, but is more likely to damage the vehicle's relays, wiring harnesses, etc., causing certain economic losses and accompanied by serious safety hazards.
[0003] Based on the above, the current commonly used Figure 2 The circuit architecture shown is used to avoid the ground short circuit fault mentioned above. Specifically, Figure 2 It is another motor power supply side circuit in the prior art, including two PMOS tubes (T1 and T2) with a common drain and a transistor (T3), the source of T1 is connected to the vehicle power supply Vbat, the source of T2 is led to the power bus 40, the load is mounted on the power bus 40, the gate of T1 and the gate of T2 are connected together and grounded through T3, and the on and off of the transistor is controlled by inputting a driving signal (MCU_IO) to T3, thereby controlling the on and off of T1 and T2. This circuit architecture has the function of bidirectional circuit shutdown, which can shut down the power supply to the load, but due to process limitations, the overcurrent capacity of the PMOS tube is relatively small and cannot meet the large current demand of the power bus, and the PMOS tube is expensive and large in size, which is not conducive to achieving the design requirements of low cost and miniaturization of the controller. And the most important point is, Figure 2 The PMOS tube in the circuit cannot quickly discharge energy when turned off, resulting in a slow shutdown speed of the PMOS tube. It can only be used in power supply applications with a small current of the power bus 40 (such as power supply applications of power management chips), and cannot meet the fast shutdown requirements under large currents. If cascade failures occur on the power supply side of the motor, high power consumption will be generated in a short time. The slow shutdown speed of the PMOS tube cannot meet the needs of fast shutdown of the circuit, posing a major safety hazard. Utility Model Content
[0004] The utility model aims to provide a power supply shutoff circuit, which can discharge the energy of a bidirectional switch during the shutoff process of the bidirectional switch, so that the bidirectional switch can be shut off quickly, meet the circuit design requirements, and improve the safety level.
[0005] In order to solve the above technical problems, the utility model provides a power supply shutoff circuit, which includes:
[0006] A bidirectional switch, wherein the input end of the bidirectional switch is used to connect to the vehicle power supply, and the output end of the bidirectional switch leads to a power bus;
[0007] an on-off driving circuit, the on-off driving circuit being connected to a driving end of the bidirectional switch and being used for driving the bidirectional switch to be turned on or off;
[0008] An energy discharge circuit is connected between the output end and the driving end of the bidirectional switch, and the energy discharge circuit is used for grounding to discharge the energy of the bidirectional switch to the ground when the bidirectional switch is turned off.
[0009] Optionally, the bidirectional switch includes a first MOS tube and a second MOS tube of the same type, the source of the first MOS tube is used to connect to the vehicle power supply, the drain of the first MOS tube is connected to the drain of the second MOS tube, the source of the second MOS tube is led out to the power bus, and the gate of the first MOS tube and the gate of the second MOS tube are connected together as the driving end of the bidirectional switch.
[0010] Optionally, both the first MOS transistor and the second MOS transistor are NMOS transistors.
[0011] Optionally, the on-off driving circuit includes a charge pump and a first resistor, and the charge pump is connected to the driving end of the bidirectional switch through the first resistor.
[0012] Optionally, the on-off drive circuit also includes a first power switch tube and a drive unit, the input end of the first power switch tube is connected to the charge pump, the output end of the first power switch tube is connected to the first resistor, and the drive end of the first power switch tube is connected to the drive unit, and the drive unit is used to drive the first power switch tube to be turned on or off.
[0013] Optionally, the first power switch tube is a PMOS tube or a PNP transistor.
[0014] Optionally, the driving unit includes a second power switch tube, the second power switch tube grounds the driving end of the first power switch tube, and the driving end of the second power switch tube is externally connected to a first driving signal.
[0015] Optionally, the second power switch tube is an NPN transistor or an NMOS tube.
[0016] Optionally, the energy discharge circuit includes a discharge branch and a discharge branch, the discharge branch is connected between the output end and the driving end of the bidirectional switch, the input end of the discharge branch is connected to the output end of the bidirectional switch, the output end of the discharge branch is used for grounding, and a line is also led out between the input end and the output end of the discharge branch to connect to the driving end of the bidirectional switch.
[0017] Optionally, the discharge branch includes a Zener diode, a second resistor and a third power switch tube, the anode end of the Zener diode is connected to the output end of the bidirectional switch, the cathode end of the Zener diode is connected to the driving end of the bidirectional switch, and the cathode end of the Zener diode is also grounded through the second resistor and the third power switch tube connected in series, and the driving end of the third power switch tube is externally connected to a second driving signal.
[0018] Optionally, the third power switch tube is an NMOS tube or an NPN transistor.
[0019] Optionally, the discharge branch includes at least one third resistor.
[0020] In summary, in the power supply shutoff circuit provided by the utility model, the power supply shutoff circuit includes a bidirectional switch, an on-off drive circuit and an energy discharge circuit, the input end of the bidirectional switch is used to connect the vehicle power supply, and the output end of the bidirectional switch leads to the power bus; the on-off drive circuit is connected to the drive end of the bidirectional switch, used to drive the bidirectional switch to turn on or off; the energy discharge circuit, the energy discharge circuit is connected between the output end and the drive end of the bidirectional switch, and the energy discharge circuit is used to ground, so that when the bidirectional switch is turned off, the energy of the bidirectional switch is discharged to the ground. In this configuration, on the one hand, the on-off drive circuit drives the bidirectional switch to turn on or off, which can meet the shutdown requirements of the bidirectional switch in the application of small current power supply of the power bus; on the other hand, when the on-off drive circuit turns off the bidirectional switch, if the bidirectional switch needs to be turned off quickly, the energy discharge circuit can be grounded, so that the voltage on the parasitic capacitor between the output end and the drive end of the bidirectional switch is quickly discharged to the ground, meeting the rapid shutdown requirements of the bidirectional switch in the application of large current power supply of the power bus. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Those skilled in the art should understand that the drawings provided are for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.
[0022] Figure 1 It is a schematic diagram of a motor power supply side circuit in the prior art;
[0023] Figure 2 It is a schematic diagram of another motor power supply side circuit in the prior art;
[0024] Figure 3 It is a schematic diagram of a power supply shutoff circuit according to an embodiment of the utility model.
[0025] In the attached figure:
[0026] Vbat-on-board power supply; 10-bidirectional switch; 20-on-off drive circuit; 21-charge pump; 30-energy discharge circuit; 31-discharge branch; 40-power bus;
[0027] Q1-first MOS tube; Q2-second MOS tube; Q3-first power switch tube; Q4-second power switch tube; Q5-third power switch tube; R1-first resistor; R2-second resistor; R3-third resistor; Z-Zener diode. DETAILED DESCRIPTION
[0028] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.
[0029] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which not only include the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise clearly indicated in the content. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0030] Figure 3 Schematic diagram of a power supply shutoff circuit according to an embodiment of the present utility model. Figure 3As shown, an embodiment of the utility model schematically provides a power supply shutdown circuit, including a bidirectional switch 10, an on-off drive circuit 20 and an energy discharge circuit 30. The input end of the bidirectional switch 10 is used to connect to the vehicle power supply Vbat, and the output end of the bidirectional switch 10 leads to the power bus 40, on which a load is mounted (the load may be, for example, a power management chip of a controller); the driving end of the bidirectional switch 10 is connected to the on-off drive circuit 20, and the on-off drive circuit 20 is used to drive the bidirectional switch 10 to turn on or off. It can be understood that the on-off drive circuit 20 is used to drive the connection or disconnection between the input end and the output end of the bidirectional switch 10. It can be understood by those skilled in the art that the bidirectional switch 10 can realize bidirectional shutdown of input and output and output and input and output for the circuit in which it is located. The energy discharge circuit 30 is connected between the output end and the drive end of the bidirectional switch 10, and the energy discharge circuit 30 is used to be grounded, so as to discharge the energy of the bidirectional switch 10 to the ground when the bidirectional switch 10 is turned off, specifically, the parasitic capacitance (C GS ) is discharged to the ground. In this way, on the first hand, the on-off drive circuit 20 can drive the bidirectional switch 10 to turn on or off, which can meet the shutdown requirements of the bidirectional switch 10 in the application scenario of small current power supply of the power bus 40. At this time, the energy discharge circuit 30 does not need to be grounded; on the second hand, when the on-off drive circuit 20 turns off the bidirectional switch 10, if it is necessary to quickly turn off the bidirectional switch 10, the energy discharge circuit 30 can be grounded, so that the voltage on the parasitic capacitor between the output end and the drive end of the bidirectional switch 10 is quickly discharged to the ground, meeting the rapid shutdown requirements of the bidirectional switch 10 in the application scenario of large current power supply of the power bus 40. The power supply circuit of the utility model can not only meet the shutdown requirements of the bidirectional switch 10 in the scenario of small current power supply of the power bus 40, but also meet the requirements of rapid shutdown of the bidirectional switch 10 in the scenario of large current power supply of the power bus 40, thereby improving the safety level.
[0031] Furthermore, the bidirectional switch 10 includes a first MOS tube Q1 and a second MOS tube Q2 of the same type, the source of the first MOS tube Q1 serves as the input end of the bidirectional switch 10, connected to the vehicle power supply Vbat, the drain of the first MOS tube Q1 is connected to the drain of the second MOS tube Q2, that is, the drain of the first MOS tube Q1 and the drain of the second MOS tube Q2 are connected as the midpoint of the bidirectional switch 10, the source of the second MOS tube Q2 serves as the output end of the bidirectional switch 10 to lead out the power bus 40, the gate of the first MOS tube Q1 and the gate of the second MOS tube Q2 are connected together as the driving end of the bidirectional switch 10, and thus connected to the on-off driving circuit 20. It can be understood that the first MOS tube Q1 also plays a role in preventing the power supply from being reversed. In this way, the parasitic capacitance between the output end and the driving end of the bidirectional switch 10 also refers to the parasitic capacitance C between the source and the gate of the second MOS tube Q2. GS.
[0032] In this embodiment, the first MOS transistor Q1 and the second MOS transistor Q2 are both NMOS transistors. In some other embodiments, the first MOS transistor Q1 and the second MOS transistor Q2 may also be PMOS transistors. Compared with PMOS transistors, NMOS transistors have the characteristics of miniaturization and low cost, which better meets the development requirements of integrated circuits of future controllers.
[0033] Furthermore, for the bidirectional switch 10 composed of the first MOS transistor Q1 and the second MOS transistor Q2, the on-off driving circuit 20 includes a charge pump 21 and a first resistor R1, and the charge pump 21 is connected to the driving end of the bidirectional switch 10 through the first resistor R1. Specifically, the charge pump 21 can be turned on or off to control whether the charge pump 21 inputs a driving voltage to the driving end of the bidirectional switch 10, so as to control the on-off of the first MOS transistor Q1 and the second MOS transistor Q2. It can be understood by those skilled in the art that the on-off of the first MOS transistor Q1 and the second MOS transistor Q2 here specifically refers to the on-off between the source and the drain of the first MOS transistor Q1, and the on-off between the source and the drain of the second MOS transistor Q2.
[0034] Further, the on-off driving circuit 20 also includes a first power switch tube Q3 and a driving unit connected to the first power switch tube Q3, the first power switch tube Q3 is connected in series between the charge pump 21 and the second resistor R2, specifically, the input end of the first power switch tube Q3 is connected to the charge pump 21, the output end of the first power switch tube Q3 is connected to the first resistor R1, the driving end of the first power switch tube Q3 is connected to the driving unit, and the driving unit is used to drive the first power tube to turn on or off. The first power switch tube Q3 can be a PMOS tube, the drain of the first power switch tube Q3 is connected to the charge pump 21, the source of the first power switch tube Q3 is connected to the first resistor R1, and the gate of the first power switch tube Q3 is connected to the driving unit. In some other embodiments, the first power switch tube Q3 can also be a PNP triode, the emitter of the first power switch tube Q3 is connected to the charge pump 21, the collector of the first power switch tube Q3 is connected to the first resistor R1, and the base of the first power switch tube Q3 is connected to the driving unit.
[0035] The driving unit includes a second power switch tube Q4, the second power switch tube Q4 grounds the driving end of the first power switch tube Q3 (the gate or base of the first power switch tube Q3Q3), and the driving end of the second power switch tube Q4 is externally connected to the first driving signal (MCU_V1). Specifically, the first driving signal is used to turn on or off the second power switch tube Q4, thereby controlling whether the driving end of the first power switch tube Q3 is grounded, and then controlling the on and off of the first power switch tube Q3. The second power switch tube Q4 can be an NPN transistor, the collector of the second power switch tube Q4 is connected to the driving end of the first power switch tube Q3, the emitter of the second power switch tube Q4 is grounded, and the base of the second power switch tube Q4 is connected to the first driving signal. In some other embodiments, the second power switch tube Q4 can also be an NMOS tube, the drain of the second power switch tube Q4 is connected to the driving end of the first power switch tube Q3, the source of the second power switch tube Q4 is grounded, and the gate of the second power switch tube Q4Q4 is connected to the first driving signal.
[0036] Further, the energy discharge circuit 30 includes a discharge branch 31 and a discharge branch, the discharge branch is connected between the output end and the driving end of the bidirectional switch 10, specifically connected between the source and the gate of the second MOS tube Q2, when the on-off drive circuit 20 turns off the bidirectional switch 10, the discharge branch can discharge the parasitic capacitance of the second MOS tube Q2 to ensure the turn-off property of the second MOS tube Q2. In one embodiment, the discharge branch includes at least one third resistor R3, and when the number of the third resistor R3 is more than one, it can be connected in parallel and / or in series between the source and the gate of the second MOS tube Q2. The input end of the discharge branch 31 is connected to the output end of the bidirectional switch 10, and the output end of the discharge branch 31 is used for grounding. A line is also drawn between the input end and the output end of the discharge branch 31 to connect to the driving end of the bidirectional switch 10. Specifically, when the on-off drive circuit 20 turns off the bidirectional switch 10, the discharge branch 31 is grounded at this time, so that the parasitic capacitance of the second MOS tube Q2 can be quickly discharged, and the voltage on the second MOS tube Q2 is quickly released to the ground end, thereby meeting the rapid shutdown requirement of the bidirectional switch 10.
[0037] Furthermore, the discharge branch 31 includes a Zener diode Z, a second resistor R2 and a third power switch tube Q5, the anode end of the Zener diode Z is connected to the output end of the bidirectional switch 10 (specifically connected to the source of the second MOS tube Q2), the cathode end of the Zener diode Z is connected to the driving end of the bidirectional switch 10 (specifically connected to the gate of the second MOS tube Q2), and the cathode end of the Zener diode Z is also connected to the ground through the second resistor R2 and the third power switch tube Q5 connected in series, and the driving end of the third power switch tube Q5 is externally connected to the second drive signal (MCU_V2), and the second drive signal is used to control the on and off of the third power switch tube Q5. When the third power switch tube Q5 is turned on, the discharge branch 31 can be grounded. It can be understood that the existence of the Zener diode Z can control the V of the second MOS tube Q2. GS The second MOS tube Q2 is clamped to protect it and deal with the interference on the power bus 40. In addition, when the bidirectional switch 10 needs to be quickly turned off, the second drive signal turns on the third power switch tube Q5. At this time, the Zener diode Z is in a forward conduction state and is grounded through the second resistor R2 and the third power switch tube Q5 to quickly discharge the parasitic capacitance of the second MOS tube Q2.
[0038] In one embodiment, the third power switch tube Q5 is an NMOS tube, the drain of the third power switch tube Q5 is connected to the second resistor R2, the source of the third power switch tube Q5 is grounded, and the gate of the third power switch tube Q5 is connected to the second drive signal. In an alternative embodiment, the third power switch tube Q5 is an NPN transistor, the collector of the third power switch tube Q5 is connected to the second resistor R2, the emitter of the third power switch tube Q5 is grounded, and the base of the third power switch tube Q5 is connected to the second drive signal.
[0039] Although the utility model is disclosed as above with preferred embodiments, the above embodiments are not intended to limit the utility model. For any technician familiar with the art, without departing from the scope of the technical solution of the utility model, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the utility model, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.
Claims
1. A power supply shutoff circuit, characterized in that: include: A bidirectional switch, wherein the input end of the bidirectional switch is used to connect to the vehicle power supply, and the output end of the bidirectional switch leads to a power bus; an on-off driving circuit, the on-off driving circuit being connected to a driving end of the bidirectional switch and being used for driving the bidirectional switch to be turned on or off; An energy discharge circuit is connected between the output end and the driving end of the bidirectional switch, and the energy discharge circuit is used for grounding to discharge the energy of the bidirectional switch to the ground when the bidirectional switch is turned off.
2. The power supply shutoff circuit according to claim 1, characterized in that: The bidirectional switch includes a first MOS tube and a second MOS tube of the same type, the source of the first MOS tube is used to connect the vehicle power supply, the drain of the first MOS tube is connected to the drain of the second MOS tube, the source of the second MOS tube leads to the power bus, and the gate of the first MOS tube and the gate of the second MOS tube are connected together as the driving end of the bidirectional switch.
3. The power supply shutoff circuit according to claim 2, characterized in that: The first MOS tube and the second MOS tube are both NMOS tubes.
4. The power supply shutoff circuit according to claim 2, characterized in that: The on-off driving circuit includes a charge pump and a first resistor, and the charge pump is connected to the driving end of the bidirectional switch through the first resistor.
5. The power supply shutoff circuit according to claim 4, characterized in that: The on-off drive circuit also includes a first power switch tube and a drive unit, the input end of the first power switch tube is connected to the charge pump, the output end of the first power switch tube is connected to the first resistor, and the drive end of the first power switch tube is connected to the drive unit, and the drive unit is used to drive the first power switch tube to turn on or off.
6. The power supply shutoff circuit according to claim 5, characterized in that: The driving unit includes a second power switch tube, the second power switch tube grounds the driving end of the first power switch tube, and the driving end of the second power switch tube is externally connected to a first driving signal.
7. The power supply shutoff circuit according to claim 1, characterized in that: The energy discharge circuit includes a discharge branch and a discharge branch, the discharge branch is connected between the output end and the driving end of the bidirectional switch, the input end of the discharge branch is connected to the output end of the bidirectional switch, the output end of the discharge branch is used for grounding, and a line is also led between the input end and the output end of the discharge branch to connect to the driving end of the bidirectional switch.
8. The power supply shutoff circuit according to claim 7, characterized in that: The discharge branch includes a Zener diode, a second resistor and a third power switch tube, the anode end of the Zener diode is connected to the output end of the bidirectional switch, the cathode end of the Zener diode is connected to the driving end of the bidirectional switch, and the cathode end of the Zener diode is also grounded through the second resistor and the third power switch tube connected in series, and the driving end of the third power switch tube is externally connected to a second driving signal.
9. The power supply shutoff circuit according to claim 8, characterized in that: The third power switch tube is an NMOS tube or an NPN transistor.
10. The power supply shutoff circuit according to claim 7, characterized in that: The discharge branch includes at least one third resistor.