A protection circuit and energy storage power supply thereof

Abstract

The utility model discloses an embodiment of a protection circuit and an energy storage power supply thereof. The protection circuit comprises a voltage detection unit, a switch control unit and an energy dissipation unit. The voltage detection unit is connected between the positive and negative poles of a bus and connected to the switch control unit. The switch control unit is connected to the energy dissipation unit and to the bus. The voltage detection unit is configured to output a drive signal when the bus voltage is greater than a preset voltage threshold. The switch control unit is configured to respond to the drive signal and turn on a dissipation loop between the energy dissipation unit and the bus. The energy dissipation unit comprises a power dissipation device for dissipating energy from the bus voltage when the dissipation loop is turned on. The utility model embodiment triggers the energy dissipation loop when the bus voltage exceeds the safety threshold, dissipates the excess energy through the power dissipation device, thereby protecting the vehicle-mounted electronic equipment from high-voltage damage, and solving the problem of abnormal surge of the bus voltage of the vehicle generator.

Description

Technical Field

[0001] This utility model relates to the field of battery management, and in particular to a protection circuit and its energy storage power supply. Background Technology

[0002] Because traditional automotive generators rely on mechanical transmission devices for energy conversion, their voltage and current regulation mechanisms suffer from significant response lag, making it difficult for their dynamic control performance to meet the real-time requirements of modern on-board electrical systems. When the parking battery charging management module fails or shuts down normally due to full charge, the electromagnetic inertia of the generator's excitation coil means that even after the charging circuit is disconnected, the magnetic field needs approximately 50-200ms to decay. During this period, the generator maintains a high electromotive force output and continues to convert mechanical energy into electrical energy. This causes a sudden surge in bus voltage, with the actual voltage reaching 32V-100V and a voltage rise rate of 50-100V / s, far exceeding the truck's rated 24V operating voltage. This abnormally high voltage can easily burn out electrical appliances inside the vehicle, such as the air conditioning, lighting system, and safety system.

[0003] Conventional parking batteries use supercapacitors as absorption devices. Due to their advantages of fast response, high power density, long cycle life, and rapid charge / discharge, they can buffer and absorb excess generator energy, stabilize the bus voltage, and protect electronic equipment when the charging tube is off. However, supercapacitors are expensive, significantly increasing system development and manufacturing costs in applications requiring multiple supercapacitors in parallel. Utility Model Content

[0004] The main technical problem solved by this utility model embodiment is to provide a protection circuit and its energy storage power supply, which can solve at least some of the defects of existing parking batteries.

[0005] In a first aspect, this utility model provides a protection circuit, comprising: a voltage detection unit, a switch control unit, and an energy dissipation unit. The voltage detection unit is connected between the positive and negative terminals of a busbar and is also connected to the switch control unit. The switch control unit is connected to both the energy dissipation unit and the busbar. The energy dissipation unit is connected to the busbar. The voltage detection unit is configured to output a drive signal when the busbar voltage is greater than a preset voltage threshold. The switch control unit is configured to, in response to the drive signal, conduct a dissipation loop between the energy dissipation unit and the busbar. The energy dissipation unit includes a power dissipation device for dissipating energy from the busbar voltage when the dissipation loop is conducted.

[0006] Optionally, when the bus voltage is less than the preset voltage threshold, the voltage detection unit stops outputting the drive signal so that the switch control unit disconnects the dissipation circuit.

[0007] Optionally, the power dissipation device is a cement resistor.

[0008] Optionally, the voltage detection unit includes a resistor R3, a Zener diode DZ1, and a Zener diode DZ2; the first end of the resistor R3 is connected to the positive terminal of the bus, the second end of the resistor R3 is connected to the cathode of the Zener diode DZ1, the anode of the Zener diode DZ1 and the cathode of the Zener diode DZ2 are both connected to the input terminal of the switch control unit, and the anode of the Zener diode DZ2 is connected to the negative terminal of the bus.

[0009] Optionally, the switch control unit includes resistors R5 and R6, and a switch transistor Q1; the first end of resistor R5 is connected to the cathode of the Zener diode DZ2, the second end of resistor R5 and the first end of resistor R6 are both connected to the gate of the switch transistor Q1, the drain of the switch transistor Q1 is connected to the second end of the energy dissipation unit, the source of the switch transistor Q1 and the second end of resistor R6 are both connected to the negative terminal of the bus, and the first end of the energy dissipation unit is connected to the positive terminal of the bus.

[0010] Optionally, the voltage detection unit includes resistor R5, resistor R9, and reference source U1; the first end of resistor R5 is connected to the positive terminal of the bus, the second end of resistor R5 and the first end of resistor R9 are both connected to the control terminal of reference source U1, the cathode of reference source U1 is connected to the input terminal of the switch control unit, and the anode of reference source U1 and the second end of resistor R9 are both connected to the negative terminal of the bus.

[0011] Optionally, the switch control unit includes resistors R4, R6, R7, and R10, a Zener diode DZ1, a switching transistor Q1, and a switching transistor Q2. The second ends of resistors R4 and R6 are both connected to the negative terminal of the reference source U1. The first end of resistor R6 and the emitter of the switching transistor Q1 are both connected to the positive terminal of the bus via a current-limiting resistor R1. The first end of resistor R4 is connected to the base of the switching transistor Q1. The collector of the switching transistor Q1 is connected to the first end of resistor R7. The second end of resistor R7, the first end of resistor R10, and the cathode of the Zener diode DZ1 are all connected to the gate of the switching transistor Q2. The drain of the switching transistor Q2 is connected to the second end of the energy dissipation unit. The source of the switching transistor Q2, resistor R10, and the anode of the Zener diode DZ1 are all connected to the negative terminal of the bus. The first end of the energy dissipation unit is connected to the positive terminal of the bus.

[0012] Optionally, the voltage detection unit includes resistors R5 and R7, and a Zener diode DZ2; the cathode of the Zener diode DZ2 is connected to the positive terminal of the bus, the anode of the Zener diode DZ2 is connected to the first end of the resistor R5, the second end of the resistor R5 and the first end of the resistor R7 are both connected to the input terminal of the switch control unit, and the second end of the resistor R7 is connected to the negative terminal of the bus.

[0013] Optionally, the switch control unit includes resistors R2, R4, and R6, a Zener diode DZ1, a switching transistor Q1, and a switching transistor Q2. The first end of resistor R2 and the cathode of Zener diode DZ1 are both connected to the positive terminal of the bus via a current-limiting resistor R1. The second end of resistor R2, the first end of resistor R4, and the anode of Zener diode DZ1 are all connected to the gate of switching transistor Q1. The second end of resistor R4 is connected to the collector of switching transistor Q2. The base of switching transistor Q2 is connected to the second end of resistor R6. The first end of resistor R6 is connected to the first end of resistor R7. The drain of switching transistor Q1 is connected to the positive terminal of the bus. The emitter of switching transistor Q2 is connected to the negative terminal of the bus. The source of switching transistor Q1 is connected to the first terminal of the energy dissipation unit, and the second terminal of the energy dissipation unit is connected to the negative terminal of the bus.

[0014] Secondly, this utility model provides an energy storage power supply, including: the protection circuit as described in the first aspect.

[0015] The beneficial effects of this utility model embodiment are as follows: Unlike the prior art, this utility model embodiment triggers an energy dissipation circuit when the bus voltage exceeds the safety threshold, dissipating excess electrical energy through a power dissipation device, thereby protecting the vehicle electronic equipment from high voltage damage and solving the problem of abnormal surges in vehicle generator bus voltage. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a schematic diagram of the structure of a protection circuit provided by an embodiment of this utility model; Figure 2 This is a circuit diagram of a protection circuit provided by an embodiment of the present invention; Figure 3 This is a circuit diagram of another protection circuit provided by an embodiment of the present invention; Figure 4 This is a circuit diagram of another protection circuit provided by an embodiment of the present invention. Detailed Implementation

[0018] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0020] In some embodiments of this application, reference is made to Figure 1 A schematic diagram of a protection circuit 10 is provided. The protection circuit 10 includes a voltage detection unit 110, a switch control unit 120, and an energy dissipation unit 130.

[0021] Specifically, the voltage detection unit 110 is connected between the positive terminal 210 and the negative terminal 220 of the busbar, and the voltage detection unit 110 is also connected to the switch control unit 120. The switch control unit 120 is connected to the energy dissipation unit 130 and the busbar, respectively, and the energy dissipation unit 130 is connected to the busbar.

[0022] Specifically, the voltage detection unit 110 is configured to output a drive signal when the bus voltage exceeds a preset voltage threshold. As an example and not a limitation, the voltage detection unit 110 monitors the voltage difference between the positive terminal 210 and the negative terminal 220 of the bus in real time. When the bus voltage exceeds the preset safe voltage threshold, the voltage comparison circuit inside the voltage detection unit 110 is triggered, thereby generating a corresponding drive signal and outputting it to the switch control unit 120.

[0023] In some embodiments of this application, the switch control unit 120 is configured to conduct the dissipation circuit between the energy dissipation unit 130 and the bus in response to a drive signal. Specifically, after receiving a drive signal from the voltage detection unit 110, the internal switching device of the switch control unit 120 changes its conduction state under the action of the drive signal, so that the originally disconnected dissipation circuit forms a conductive path, thereby realizing the electrical connection between the energy dissipation unit 130 and the bus.

[0024] In some embodiments of this application, the energy dissipation unit 130 includes a power dissipation device for dissipating energy from the bus voltage when the dissipation circuit is activated. By way of example and not limitation, the power dissipation device may be one or more of a cement resistor, a wire-wound power resistor, a thick-film power resistor, and a ceramic power resistor. In some embodiments, the power dissipation device may also be a braking resistor, a discharge resistor module, or other device specifically designed for energy dissipation. When the dissipation circuit is activated, the overvoltage energy on the bus is converted into heat energy by the power dissipation device, effectively reducing the bus voltage and preventing damage to onboard electronic equipment caused by overvoltage.

[0025] In some embodiments of this application, when the bus voltage returns to normal, the protection circuit 10 can automatically stop the energy dissipation operation. Specifically, when the bus voltage is less than a preset voltage threshold, the voltage detection unit 110 stops outputting the drive signal so that the switch control unit 120 disconnects the dissipation circuit.

[0026] When the bus voltage drops below a preset voltage threshold, the voltage comparison circuit inside the voltage detection unit 110 detects that the voltage has recovered to a safe range, and at this time, it stops generating a drive signal. After losing the drive signal, the internal switching device of the switch control unit 120 returns to the open state, thereby cutting off the dissipation loop between the energy dissipation unit 130 and the bus, so that the protection circuit 10 returns to the standby state, waiting for the next overvoltage event to occur.

[0027] In some embodiments of this application, reference is made to Figure 2 A specific circuit diagram of a protection circuit is provided. In this embodiment, the protection circuit also includes a current-limiting resistor R1, which is used to limit the current in the circuit and prevent damage to circuit components due to excessive current. Specifically, the current-limiting resistor R1 is connected in series between the positive terminal 210 of the busbar and other parts of the circuit, serving as a current protection function.

[0028] In some embodiments of this application, the voltage detection unit 110 includes a resistor R3, a Zener diode DZ1, and a Zener diode DZ2. The first end of the resistor R3 is connected to the positive terminal 210 of the bus through a current-limiting resistor R1, and the second end of the resistor R3 is connected to the cathode of the Zener diode DZ1.

[0029] The anode of Zener diode DZ1 and the cathode of Zener diode DZ2 are both connected to the input terminal of switch control unit 120, and the anode of Zener diode DZ2 is connected to the negative terminal of bus 220. Zener diodes DZ1 and DZ2 are configured in series to form a voltage divider circuit. When the bus voltage exceeds the sum of the regulated voltages of the two Zener diodes, the voltage divider circuit starts to work, generating a sufficient drive voltage at the input terminal of switch control unit 120.

[0030] Resistor R3, together with Zener diodes DZ1 and DZ2, constitutes a voltage detection circuit. When the voltage at the positive terminal 210 of the bus is normal, Zener diode DZ1 is in the off state because the voltage has not reached the conduction threshold of the Zener diode, and the voltage detection unit 110 does not output a drive signal. When the voltage at the positive terminal 210 of the bus exceeds the preset voltage threshold, Zener diode DZ1 begins to conduct. Through the voltage division effect of resistor R3, Zener diode DZ1, and Zener diode DZ2, a drive signal is generated at the input terminal of the switch control unit 120.

[0031] In this embodiment, the protection circuit also includes a fuse F1, which is used to cut off the circuit in time when an abnormally large current occurs in the circuit, providing overcurrent protection.

[0032] The switch control unit 120 includes resistors R5 and R6, and a switching transistor Q1. Specifically, the first terminal of resistor R5 is connected to the cathode of the Zener diode DZ2, and the second terminal of resistor R5 and the first terminal of resistor R6 are both connected to the gate of the switching transistor Q1. By way of example and not limitation, the switching transistor Q1 is an N-type MOSFET whose gate receives a drive signal from the voltage detection unit 110.

[0033] In some embodiments of this application, the drain of the switching transistor Q1 is connected to the second terminal of the energy dissipation unit 130, and the source of the switching transistor Q1 and the second terminal of the resistor R6 are both connected to the negative terminal of the bus 220. The resistor R6 acts as a pull-down resistor to ensure that the switching transistor Q1 can be reliably turned off when there is no driving signal, preventing the occurrence of false turn-on.

[0034] Specifically, the first terminal of the energy dissipation unit 130 is connected to the positive terminal 210 of the bus via a fuse F1 and a current-limiting resistor R1. When the voltage detection unit 110 outputs a drive signal, the gate voltage of the switch Q1 is greater than the source voltage, causing the switch Q1 to conduct, thereby forming a conductive path from the positive terminal 210 of the bus through the current-limiting resistor R1, the fuse F1, the energy dissipation unit 130, the switch Q1 to the negative terminal 220 of the bus.

[0035] In some embodiments of this application, the protection circuit further includes resistors R2 and R4, capacitors C1 and C2, forming an RC filter absorption circuit. The RC filter circuit can effectively suppress high-frequency interference signals in the circuit and improve the stability of the circuit operation.

[0036] Specifically, the first terminal of resistor R2 is connected to the first terminal of resistor R3, the second terminal of resistor R2 is connected to the first terminal of capacitor C2, and the second terminal of capacitor C2 is connected to the negative terminal of bus 220. As an example and not a limitation, resistor R2 and capacitor C2 constitute the first part of the RC filter circuit, which is used to filter the bus voltage and reduce the impact of voltage fluctuations on the operating accuracy of voltage detection unit 110.

[0037] In this embodiment, the first terminal of capacitor C1 is connected to the cathode of Zener diode DZ1, the second terminal of capacitor C1 is connected to the first terminal of resistor R4, and the second terminal of resistor R4 is connected to the drain of switching transistor Q1. It is easy to understand that capacitor C1 and resistor R4 constitute the second part of the RC filter circuit, whose main function is to buffer the switching process of switching transistor Q1, reducing voltage spikes and electromagnetic interference generated during switching.

[0038] Specifically, when the voltage of the positive terminal 210 of the bus is normal and less than the preset voltage threshold, the Zener diode DZ1 is not turned on, the voltage detection unit 110 does not output a drive signal, the switching transistor Q1 is in the off state, the energy dissipation circuit is disconnected, and the energy dissipation unit 130 does not work.

[0039] When the voltage at the positive terminal 210 of the bus exceeds the preset voltage threshold, due to the voltage division effect of resistor R3, Zener diode DZ1, and Zener diode DZ2, the gate voltage of switch Q1 is greater than the source voltage, causing switch Q1 to conduct. It is easy to understand that after switch Q1 conducts, the high voltage at the positive terminal 210 of the bus, exceeding the preset threshold, forms a conductive circuit through the current-limiting resistor R1, fuse F1, energy dissipation unit 130, and switch Q1, thus dissipating energy.

[0040] The power dissipation device in the energy dissipation unit 130 converts overvoltage energy into heat energy for dissipation, thereby effectively protecting the vehicle electronic equipment from overvoltage damage. When the bus voltage returns to normal, the Zener diode DZ1 is turned off, the switching transistor Q1 is turned off accordingly, the energy dissipation circuit is disconnected, and the circuit returns to standby mode.

[0041] In this embodiment, the power dissipation device in the energy dissipation unit 130 is a cement resistor, such as... Figure 2 As shown, the energy dissipation unit 130 includes a cement resistor RT1.

[0042] Cement resistors can withstand abnormally high voltages of 32V to 100V and meet the demands of high-power energy dissipation. When the bus voltage spikes abnormally, the cement resistor quickly converts the overvoltage energy into heat energy through its internal resistive material and effectively dissipates heat through its external cement encapsulation material, preventing excessive temperature from affecting circuit performance.

[0043] In this implementation, the resistance value of the cement resistor needs to balance energy dissipation efficiency and heat dissipation capacity. Too low a resistance value may lead to excessive current, impacting other components in the circuit; too high a resistance value may affect energy dissipation and prevent timely reduction of the bus voltage. Specifically, the power rating of the cement resistor is typically selected to be 2-3 times the actual operating power to ensure reliable operation under continuous operation or instantaneous high-power surges. As an example, and not a limitation, for 24V truck systems, cement resistors with a power rating of 10W-50W and a resistance range of 1Ω-10Ω can be selected, effectively absorbing energy while ensuring circuit safety.

[0044] In this implementation, the current-limiting resistor R1 and the fuse F1 provide dual protection. The current-limiting resistor R1 limits the normal operating current, while the fuse F1 blows to protect against abnormally high currents. The RC filter circuit ensures that the circuit can operate stably and reliably under various electromagnetic environments, improving the overall performance and reliability of the protection circuit.

[0045] In other embodiments of this application, reference is made to Figure 3The diagram provides a specific circuit schematic for another protection circuit. In this embodiment, the protection circuit also includes a current-limiting resistor R1 to limit the current in the circuit and ensure that the circuit devices operate within a safe current range. Specifically, the current-limiting resistor R1 is connected in series between the positive terminal 210 of the busbar and other parts of the circuit, providing basic current protection.

[0046] In some embodiments of this application, the voltage detection unit 110 includes resistors R5 and R9 and a reference source U1. By way of example and not limitation, the reference source U1 is a TL431 adjustable precision parallel regulator, which can provide accurate voltage reference and comparison functions, and has higher accuracy and better temperature stability than a Zener diode.

[0047] Specifically, the first end of resistor R5 is connected to the positive terminal of bus 210 through current-limiting resistor R1, and the second end of resistor R5 and the first end of resistor R9 are both connected to the control terminal of reference source U1. As an example and not a limitation, resistors R5 and R9 form a voltage divider circuit, which proportionally divides the bus voltage and inputs it to the control terminal of reference source U1. When the divided voltage exceeds the internal reference voltage of reference source U1, reference source U1 starts to conduct.

[0048] The cathode of reference source U1 is connected to the input terminal of switch control unit 120, and the anode of reference source U1 and the second terminal of resistor R9 are both connected to the negative terminal of bus 220. When the bus voltage is normal, the voltage division value of resistors R5 and R9 is less than the reference voltage of reference source U1, and reference source U1 is in the off state, not outputting a drive signal. When the bus voltage exceeds a preset voltage threshold, the voltage division value is greater than the reference voltage, reference source U1 is turned on, its cathode voltage is pulled low, thereby outputting a drive signal to switch control unit 120.

[0049] In some embodiments of this application, the protection circuit also includes a fuse F1 to provide overcurrent protection. The switch control unit 120 includes resistors R4, R6, R7, and R10, a Zener diode DZ1, a switching transistor Q1, and a switching transistor Q2, forming a two-stage switch control circuit to improve the reliability and control accuracy of the circuit.

[0050] Specifically, the second terminals of resistors R4 and R6 are both connected to the cathode of the reference source U1, and the first terminal of resistor R6 and the emitter of the switching transistor Q1 are both connected to the positive terminal of bus 210 through the current-limiting resistor R1. By way of example and not limitation, the switching transistor Q1 is a PNP transistor, which serves as the first-stage switching device and receives the control signal from the reference source U1.

[0051] In this embodiment, the first terminal of resistor R4 is connected to the base of switching transistor Q1, and the collector of switching transistor Q1 is connected to the first terminal of resistor R7. When the reference source U1 is turned on, its cathode voltage is pulled low, and the base of switching transistor Q1 is pulled to a lower potential through resistor R4. Since the emitter is connected to the high potential of the positive terminal 210 of the bus through resistor R6, a sufficient voltage difference is formed between the base and the emitter, causing the PNP transistor Q1 to turn on.

[0052] Specifically, the second terminal of resistor R7, the first terminal of resistor R10, and the cathode of Zener diode DZ1 are all connected to the gate of switching transistor Q2, and the drain of switching transistor Q2 is connected to the second terminal of energy dissipation unit 130. By way of example and not limitation, switching transistor Q2 is an N-type MOSFET, which is used as the second-stage switching device and its conduction state is controlled by the first-stage switching transistor Q1.

[0053] In some embodiments of this application, the source of switch Q2, the second terminal of resistor R10, and the anode of Zener diode DZ1 are all connected to the negative terminal of bus 220. Specifically, when switch Q1 is turned on, current flows through resistor R7 to the gate of switch Q2. Due to the voltage division effect of resistors R7 and R10, the gate voltage of switch Q2 increases. When the gate voltage is greater than the source voltage and exceeds the turn-on threshold of switch Q2, switch Q2 turns on.

[0054] Zener diode DZ1 is connected between the gate and source of switching transistor Q2. Its main function is to protect the gate of switching transistor Q2 from overvoltage damage and ensure that switching transistor Q2 can be turned on stably and reliably. When the gate voltage is too high, Zener diode DZ1 conducts, clamping the gate voltage within a safe range.

[0055] The first end of the energy dissipation unit 130 is connected to the positive terminal of the bus 210 through the fuse F1 and the current-limiting resistor R1. When both stages of switching devices are turned on, a complete conductive path is formed from the positive terminal of the bus 210 through the current-limiting resistor R1, the fuse F1, the energy dissipation unit 130, the switching transistor Q2 to the negative terminal of the bus 220.

[0056] In some embodiments of this application, the protection circuit further includes resistors R2, R3, and R8, capacitors C1, C2, and C3, forming a multi-stage RC filter network to effectively suppress various interference signals in the circuit.

[0057] Specifically, the first terminal of resistor R2 is connected to the first terminal of resistor R5, the second terminal of resistor R2 is connected to the first terminal of capacitor C1, and the second terminal of capacitor C1 is connected to the negative terminal of the bus 220. Resistor R2 and capacitor C1 constitute the first-stage RC filter circuit, which mainly performs primary filtering on the input bus voltage to reduce the impact of voltage fluctuations and high-frequency noise on voltage detection accuracy.

[0058] In this embodiment, the first terminal of resistor R3 is connected to the first terminal of resistor R5, the second terminal of resistor R3 is connected to the first terminal of capacitor C3, and the second terminal of capacitor C3 is connected to the first terminal of resistor R9. Resistor R3 and capacitor C3 constitute a second-stage RC filter circuit, which further filters the voltage detection signal and improves the stability of the reference source U1.

[0059] Specifically, the first terminal of capacitor C2 is connected to the second terminal of resistor R5, the second terminal of capacitor C2 is connected to the first terminal of resistor R8, and the second terminal of resistor R8 is connected to the second terminal of resistor R4. Capacitor C2 and resistor R8 constitute the third-stage RC filter circuit, which mainly filters the control signal to ensure that the switch control unit 120 can receive a stable control signal and avoid malfunctions caused by signal fluctuations.

[0060] In some embodiments of this application, when the voltage at the positive terminal 210 of the bus is normal and less than a preset voltage threshold, the voltage division value of resistors R5 and R9 is less than the internal reference voltage of the reference source U1, and the reference source U1 is in a high-resistance state and is not conducting. At this time, the base potential of the switch Q1 is close to the emitter potential, the switch Q1 is turned off, the gate of the switch Q2 has no driving voltage and is also in the off state, and the entire energy dissipation circuit is disconnected.

[0061] When the voltage at the positive terminal of the busbar 210 exceeds the preset voltage threshold, the voltage division value of resistors R5 and R9 is greater than the reference voltage of the reference source U1, and the reference source U1 begins to conduct, pulling its cathode voltage down. After the reference source U1 conducts, the base of the switching transistor Q1 is pulled to a lower potential through resistor R4, while the emitter remains at a higher potential, forming a sufficient base-emitter voltage difference to turn on the PNP transistor Q1.

[0062] In this operating state, after switch Q1 is turned on, current flows from its emitter through its collector and resistor R7 to the gate of switch Q2. Due to the voltage division effect of resistors R7 and R10, the gate voltage of switch Q2 gradually increases. When the gate voltage exceeds the turn-on threshold of switch Q2, N-type MOSFET Q2 turns on, thus establishing an energy dissipation loop.

[0063] Specifically, after both switching devices are turned on, the overvoltage energy of the positive terminal 210 of the bus forms a conductive circuit through the current-limiting resistor R1, fuse F1, energy dissipation unit 130, and switching transistor Q2. The power dissipation device in the energy dissipation unit 130 converts the overvoltage energy into heat energy for dissipation, effectively reducing the bus voltage and protecting the vehicle electronic equipment.

[0064] In some embodiments of this application, when the bus voltage returns to the normal range, the voltage division value of resistors R5 and R9 decreases below the reference voltage of reference source U1, reference source U1 is turned off, and its cathode voltage rises. Switch Q1 is turned off after losing the drive signal, and the gate of switch Q2 is also turned off after losing the drive voltage. The energy dissipation circuit is disconnected, and the circuit automatically returns to the standby state.

[0065] In this embodiment, the power dissipation device in the energy dissipation unit 130 is a cement resistor, such as... Figure 3 As shown, the energy dissipation unit 130 includes a cement resistor RT1.

[0066] In other embodiments of this application, reference is made to Figure 4 This provides a specific circuit diagram for another protection circuit. In this embodiment, the protection circuit also includes a current-limiting resistor R1 to limit the current in the circuit and ensure that the circuit devices operate within a safe operating range. Specifically, the current-limiting resistor R1 is connected in series between the positive terminal 210 of the busbar and other parts of the circuit, playing a basic current protection role and preventing damage to the circuit devices due to excessive current.

[0067] In some embodiments of this application, the voltage detection unit 110 includes resistors R5 and R7, and a Zener diode DZ2. Specifically, the cathode of the Zener diode DZ2 is connected to the positive terminal 210 of the bus via a current-limiting resistor R1, and the anode of the Zener diode DZ2 is connected to the first end of resistor R5. The Zener diode DZ2 is configured with an appropriate voltage regulation value. When the bus voltage exceeds this value, the Zener diode DZ2 begins to conduct, generating a stable voltage signal at its anode.

[0068] The second end of resistor R5 and the first end of resistor R7 are both connected to the input terminal of switch control unit 120. The second end of resistor R7 is connected to the negative terminal of bus 220. Resistors R5 and R7 form a voltage divider circuit. When Zener diode DZ2 is turned on, the voltage divider effect generates an appropriate drive signal at the input terminal of switch control unit 120.

[0069] Specifically, when the bus voltage is normal and less than the Zener diode DZ2's regulated voltage, the Zener diode DZ2 is in the off state, and the voltage at the connection point between resistors R5 and R7 is close to the potential of the negative terminal 220 of the bus. The voltage detection unit 110 does not output a valid drive signal. When the bus voltage exceeds a preset voltage threshold, the Zener diode DZ2 turns on, and its anode voltage is clamped at the regulated value. Through the voltage division effect of resistors R5 and R7, a sufficient drive voltage is generated at the input terminal of the switch control unit 120.

[0070] In some embodiments of this application, the protection circuit also includes a fuse F1 to provide reliable overcurrent protection. The switch control unit 120 includes resistors R2, R4, and R6, a Zener diode DZ1, a switching transistor Q1, and a switching transistor Q2, forming a dual-switch control circuit, which significantly improves the reliability and control accuracy of the circuit.

[0071] Specifically, the first terminal of resistor R2 and the cathode of Zener diode DZ1 are both connected to the positive terminal of bus 210 through current-limiting resistor R1. Resistor R2 acts as a pull-up resistor, ensuring that the P-type MOSFET Q1 can be reliably turned off when there is no control signal, preventing false turn-on. The Zener diode DZ1 is mainly used to protect the gate of the P-type MOSFET Q1, preventing damage to the device due to excessive gate voltage.

[0072] In this embodiment, the second terminal of resistor R2, the first terminal of resistor R4, and the anode of Zener diode DZ1 are all connected to the gate of switching transistor Q1. By way of example and not limitation, switching transistor Q1 is a P-type MOSFET, which serves as the second-stage switching device, and its conduction state is controlled by the first-stage NPN transistor Q2.

[0073] Specifically, the second terminal of resistor R4 is connected to the collector of switching transistor Q2, the base of switching transistor Q2 is connected to the second terminal of resistor R6, and the first terminal of resistor R6 is connected to the first terminal of resistor R7. By way of example and not limitation, switching transistor Q2 is an NPN transistor, serving as the first-stage switching device, receiving a control signal from voltage detection unit 110. When the base voltage is higher than the emitter voltage and exceeds the conduction threshold, NPN transistor Q2 is turned on.

[0074] In some embodiments of this application, the drain of the switching transistor Q1 is connected to the second terminal of the energy dissipation unit 130, the first terminal of the energy dissipation unit 130 is connected to the positive terminal 210 of the bus via a fuse F1 and a current-limiting resistor R1, and the emitter of the switching transistor Q2 is connected to the negative terminal 220 of the bus. Specifically, the source of the switching transistor Q1 is connected to the negative terminal 220 of the bus.

[0075] When both switching devices are turned on, a complete conductive path is formed from the positive terminal 210 of the bus, through the current-limiting resistor R1, the fuse F1, the energy dissipation unit 130, the switching transistor Q1, to the negative terminal 220 of the bus. Among them, the P-type MOSFET Q1 undertakes the main power switching function, while the NPN transistor Q2 is responsible for the processing and amplification of the control signal.

[0076] In some embodiments of this application, the protection circuit further includes a resistor R3 and a capacitor C1, forming an RC filter circuit to suppress high-frequency interference signals in the circuit and improve the stability of circuit operation. Specifically, the first terminal of resistor R3 is connected to the cathode of Zener diode DZ2, the second terminal of resistor R3 is connected to the first terminal of capacitor C1, and the second terminal of capacitor C1 is connected to the negative terminal 220 of the bus. Resistor R3 and capacitor C1 constitute an input filter circuit, which mainly filters the bus voltage to reduce the impact of voltage fluctuations and high-frequency noise on voltage detection accuracy.

[0077] In some embodiments of this application, when the voltage at the positive terminal 210 of the bus is normal and less than a preset voltage threshold, the Zener diode DZ2 is in the off state and does not conduct. It is easy to understand that at this time, the current in the voltage divider circuit of resistors R5 and R7 is very small, the base voltage of the switching transistor Q2 is close to the potential of the negative terminal 220 of the bus, and lower than the emitter potential, so the NPN transistor Q2 is in the off state.

[0078] Specifically, when switch Q2 is off, its collector voltage is close to the power supply voltage connected to resistor R4, and the gate of switch Q1 is pulled up to a potential close to the positive terminal 210 of the bus through resistor R2. For P-type MOSFET Q1, when the gate voltage is close to the source voltage, the gate-source voltage difference is insufficient to turn it on, so switch Q1 is in the off state, and the entire energy dissipation circuit is broken.

[0079] In this operating state, the energy dissipation unit 130 is not working, the circuit is in standby mode, and the power consumption is extremely low. Only a few components such as resistors R2 and R3 have a small static current, and the standby power consumption of the entire circuit can be controlled at the milliwatt level, making it suitable for long-term automotive applications.

[0080] Specifically, when the voltage at the positive terminal of the bus 210 exceeds the preset voltage threshold, the Zener diode DZ2 starts to conduct, and its anode voltage is clamped at the regulated value. At this time, through the voltage division effect of resistors R5 and R7, the base voltage of the switching transistor Q2 increases. When the base voltage exceeds the emitter voltage and reaches the conduction threshold of the NPN transistor, the switching transistor Q2 conducts.

[0081] In some embodiments of this application, after switch Q2 is turned on, its collector voltage is pulled down to near the emitter potential. The gate voltage of switch Q1 is pulled down to a lower potential through resistor R4, while the source remains at a high potential at the positive terminal 210 of the bus, forming a sufficient gate-source voltage difference to turn on the P-type MOSFET Q1.

[0082] Specifically, after the switching transistor Q1 is turned on, a conductive path is established from the positive terminal 210 of the bus, through the current-limiting resistor R1, the fuse F1, the energy dissipation unit 130, and the switching transistor Q1 to the negative terminal 220 of the bus. Overvoltage energy on the bus flows into the energy dissipation unit 130 through this conductive path, where the power dissipation devices convert electrical energy into heat energy for dissipation, thereby effectively reducing the bus voltage and protecting the vehicle's electronic equipment from overvoltage damage.

[0083] In this embodiment, the power dissipation device in the energy dissipation unit 130 is a cement resistor, such as... Figure 4 As shown, the energy dissipation unit 130 includes a cement resistor RT1.

[0084] In some embodiments of this application, current-limiting resistors R1, R4, and R6 provide multiple current-limiting protection functions. It is easy to understand that current-limiting resistor R1 limits the main circuit current to prevent excessive current during energy dissipation; resistor R4 limits the drive current of the gate of switch Q1; and resistor R6 limits the drive current of the base of switch Q2, ensuring that each switching device operates within its safe operating area.

[0085] Specifically, the Zener diode DZ1 is connected to the gate of the switching transistor Q1, and its main function is to protect the gate of the P-type MOSFET from overvoltage damage. When the gate voltage rises abnormally, the Zener diode DZ1 turns on, clamping the gate voltage within a safe range and preventing the gate oxide layer from breaking down.

[0086] In this embodiment, resistor R2 acts as a pull-up resistor, ensuring that the switching transistor Q1 can be stably turned off without breakdown when there is no control signal. The presence of pull-up resistor R2 keeps the gate of the switching transistor Q1 at a high potential in the default state, ensuring reliable turn-off of the P-type MOSFET and avoiding false turn-on due to a floating or low gate potential. Fuse F1 provides a final protection barrier, melting and cutting off the circuit in time when an abnormally large current occurs in the circuit.

[0087] When the bus voltage returns to the normal range, Zener diode DZ2 turns off, and the driving capability of the voltage divider circuit with resistors R5 and R7 disappears. The base voltage of switch Q2 drops below the cutoff threshold, NPN transistor Q2 turns off, and its collector voltage rises. After switch Q2 turns off, the gate of switch Q1 is pulled up to a high potential again through resistor R2, and P-type MOSFET Q1 loses its conduction condition and turns off. The energy dissipation circuit is disconnected, and the circuit automatically returns to standby mode, waiting for the next overvoltage event to occur.

[0088] Unlike existing technologies, this utility model embodiment triggers an energy dissipation circuit when the bus voltage exceeds a safety threshold, dissipating excess electrical energy through a power dissipation device, thereby protecting on-board electronic equipment from high-voltage damage and solving the problem of abnormally high voltage spikes in vehicle generator bus voltage.

[0089] Based on the protection circuits provided in the above embodiments, some embodiments of this application also provide an energy storage power supply, which includes the protection circuits described in any of the above embodiments. This energy storage power supply is mainly used in vehicle electrical systems to provide a stable power supply for onboard electronic devices.

[0090] Specifically, the energy storage power supply includes a parking battery, a charging management module, a generator, and a protection circuit. As an example and not a limitation, the parking battery, as the main energy storage unit, is connected to the vehicle's generator through the charging management module. It charges the battery when the generator is working and supplies power to the vehicle's equipment when the generator is not working.

[0091] In this embodiment, the protection circuit is connected between the positive terminal 210 and the negative terminal 220 of the energy storage power supply bus. When the charging management module shuts down the charging circuit due to a fully charged battery or a malfunction, the electromagnetic inertia of the generator excitation coil causes an abnormal surge in the bus voltage. At this time, the protection circuit automatically activates to dissipate the overvoltage energy. Under normal operating conditions, the protection circuit is in standby mode and does not affect the normal charging and discharging function of the energy storage power supply. When the bus voltage is abnormal, the protection circuit responds quickly, effectively protecting electronic equipment such as the vehicle's air conditioning, lighting system, and safety system from overvoltage damage.

[0092] It should be noted that while the preferred embodiments of this utility model are provided in the specification and accompanying drawings, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of this utility model; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this utility model. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this utility model specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A protection circuit, characterized by, The application relates to a voltage detection unit, a switch control unit and an energy dissipation unit. The voltage detection unit is connected between the positive pole and the negative pole of a bus, and is also connected with the switch control unit; the switch control unit is connected with the energy dissipation unit and the bus respectively; and the energy dissipation unit is connected with the bus. The voltage detection unit is configured to output a driving signal when the bus voltage is greater than a preset voltage threshold. The switch control unit is configured to turn on a dissipation loop between the energy dissipation unit and the bus in response to the driving signal. The energy dissipation unit comprises a power dissipation device for dissipating energy of the bus voltage when the dissipation loop is turned on. When the bus voltage is less than the preset voltage threshold, the voltage detection unit stops outputting the driving signal, so that the switch control unit turns off the dissipation loop.

2. The circuit of claim 1, wherein, The power dissipation device is a cement resistor.

3. The circuit of claim 1, wherein, The voltage detection unit comprises a resistor R3, a stabilizing diode DZ1 and a stabilizing diode DZ2.

4. The circuit of claim 1, wherein, The first end of the resistor R3 is connected with the positive pole of the bus, the second end of the resistor R3 is connected with the cathode of the stabilizing diode DZ1, the anode of the stabilizing diode DZ1 and the cathode of the stabilizing diode DZ2 are connected with the input end of the switch control unit, and the anode of the stabilizing diode DZ2 is connected with the negative pole of the bus. The switch control unit comprises a resistor R5, a resistor R6 and a switch tube Q1.

5. The circuit of claim 4, wherein, The first end of the resistor R5 is connected with the cathode of the stabilizing diode DZ2, the second end of the resistor R5 and the first end of the resistor R6 are connected with the gate of the switch tube Q1, the drain of the switch tube Q1 is connected with the second end of the energy dissipation unit, the source of the switch tube Q1 and the second end of the resistor R6 are connected with the negative pole of the bus, and the first end of the energy dissipation unit is connected with the positive pole of the bus. The voltage detection unit comprises a resistor R5, a resistor R9 and a reference source U1.

6. The circuit of claim 1, wherein, The first end of the resistor R5 is connected with the positive pole of the bus, the second end of the resistor R5 and the first end of the resistor R9 are connected with the control end of the reference source U1, the cathode of the reference source U1 is connected with the input end of the switch control unit, and the anode of the reference source U1 and the second end of the resistor R9 are connected with the negative pole of the bus. The switch control unit comprises a resistor R4, a resistor R6, a resistor R7, a resistor R10, a stabilizing diode DZ1, a switch tube Q1 and a switch tube Q2.

7. The circuit of claim 6, wherein, ​ The second end of the resistor R4 and the second end of the resistor R6 are connected to the negative pole of the reference source U1, the first end of the resistor R6 and the emitter of the switch tube Q1 are connected to the positive pole of the bus through the current-limiting resistor R1, the first end of the resistor R4 and the base of the switch tube Q1 are connected, the collector of the switch tube Q1 and the first end of the resistor R7 are connected, the second end of the resistor R7, the first end of the resistor R10 and the cathode of the voltage stabilizing diode DZ1 are connected to the gate of the switch tube Q2, the drain of the switch tube Q2 and the second end of the energy dissipation unit are connected, the source of the switch tube Q2, the resistor R10 and the anode of the voltage stabilizing diode DZ1 are connected to the negative pole of the bus, and the first end of the energy dissipation unit is connected to the positive pole of the bus.

8. The circuit of claim 1, wherein, The voltage detection unit comprises a resistor R5, a resistor R7 and a voltage stabilizing diode DZ2. The cathode of the voltage stabilizing diode DZ2 is connected to the positive pole of the bus, the anode of the voltage stabilizing diode DZ2 and the first end of the resistor R5 are connected, the second end of the resistor R5 and the first end of the resistor R7 are connected to the input end of the switch control unit, and the second end of the resistor R7 and the negative pole of the bus are connected.

9. The circuit of claim 8, wherein, The switch control unit comprises a resistor R2, a resistor R4, a resistor R6, a voltage stabilizing diode DZ1, a switch tube Q1 and a switch tube Q2. The first end of the resistor R2 and the cathode of the voltage stabilizing diode DZ1 are connected to the positive pole of the bus through the current-limiting resistor R1, the second end of the resistor R2, the first end of the resistor R4 and the anode of the voltage stabilizing diode DZ1 are connected to the gate of the switch tube Q1, the second end of the resistor R4 and the collector of the switch tube Q2 are connected, the base of the switch tube Q2 and the second end of the resistor R6 are connected, the first end of the resistor R6 and the first end of the resistor R7 are connected, the drain of the switch tube Q1 is connected to the positive pole of the bus, the emitter of the switch tube Q2 and the negative pole of the bus are connected, the source of the switch tube Q1 and the first end of the energy dissipation unit are connected, and the second end of the energy dissipation unit and the negative pole of the bus are connected.

10. An energy storage power supply, characterized by, The protective circuit comprises: The protective circuit according to any one of claims 1-9.

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