A direct current self-holding electronic switch

Abstract

The application discloses a direct-current self-holding electronic switch with under-voltage, over-current and short-circuit protection functions, which comprises a power conversion circuit, a self-holding circuit, an under-voltage driving circuit, an over-current and short-circuit driving circuit, a module switch circuit, an input connector P1 and an output connector P2. The application has the advantages of small driving signal power, wide driving voltage range, simple circuit structure, small size, light weight and convenient installation. In addition, the application uses mature industrial devices such as resistors, capacitors, diodes, MOS tubes and optical couplings, and has low cost and high reliability.

Description

A DC self-holding electronic switch Technical Field

[0001] This invention belongs to the field of detection and control technology, specifically relating to a DC self-holding electronic switch with undervoltage, overcurrent, and short-circuit protection functions. Background Technology

[0002] In lithium primary battery packs, there is a need for a small, lightweight, low-power, low-cost, highly reliable switching device that provides undervoltage, overcurrent, and short-circuit protection and can maintain its protection state without interrupting power. The function of this device is to quickly disconnect the battery pack output when over-discharge causes undervoltage, overcurrent, or short circuit during battery pack operation.

[0003] Currently, the commonly used technical approach is to use aerospace-grade self-holding relays as switches, which brings several problems: first, aerospace-grade self-holding relays are expensive; second, self-holding relays are large in size and weight; and third, self-holding relays have high drive signal power. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the prior art, the purpose of this invention is to provide a DC self-holding electronic switch suitable for low-voltage, low-power lithium primary battery packs, with undervoltage, overcurrent, and short-circuit protection functions.

[0005] The technical solution adopted by this invention to solve its technical problem is: a DC self-holding electronic switch, including a power conversion circuit, a self-holding circuit, an undervoltage drive circuit, an overcurrent and short-circuit drive circuit, a modular switching circuit, an input connector P1, and an output connector P2; the power conversion circuit includes a diode D4, a resistor R5, a capacitor C3, and a Zener diode Z1, wherein the anode of diode D4 is connected to pin 1 of input connector P1, the cathode of diode D4 is connected to resistor R5, the other end of resistor R5 is connected to the cathode of Zener diode Z1, the anode of Zener diode Z1 is connected to pin 2 of input connector P1, and capacitor C3 is connected in parallel with Zener diode Z1; the self-holding circuit includes resistors R1 to R4. The circuit consists of capacitors C1-C2 and optocouplers U1-U4. Resistor R1 has one end connected to the collector of transistor Q2 in the overcurrent and short-circuit drive circuit, and the other end connected to the positive source terminal of optocoupler U1. The negative source terminal of optocoupler U1 is connected to pin 2 of input connector P1. Capacitor C1 is connected in parallel with the positive and negative source terminals of optocoupler U1. Resistor R2 has one end connected to the negative terminal of Zener diode Z1 in the power conversion circuit, and the other end connected to the positive source terminal of optocoupler U2. The negative source terminal of optocoupler U2 is connected to resistor R13 in the undervoltage drive circuit. Resistor R3 is connected in parallel with the positive and negative source terminals of capacitor C2 and optocoupler U3. The secondary terminals of optocouplers U1-U3 are connected in parallel, with the positive terminal of the secondary terminal connected to the negative terminal of Zener diode Z1 in the power conversion circuit. The negative terminal is connected to the positive terminal of the source of optocoupler U3, and the negative terminal of the source of optocoupler U3 is connected to the positive terminal of the source of optocoupler U4. The negative terminal of the source of optocoupler U4 is connected to resistor R4, and the other end of resistor R4 is connected to pin 2 of input connector P1. The positive terminal of the secondary terminal of optocoupler U4 is connected to the source of MOSFET Q1 in the module switching circuit, and the negative terminal of the secondary terminal of optocoupler U4 is connected to the gate of MOSFET Q1 in the module switching circuit. The undervoltage drive circuit includes a Zener diode Z4, transistors Q4-Q5, capacitor C9, and resistors R13-R17. The negative terminal of Zener diode Z4 is connected to pin 1 of input connector P1, the positive terminal of Zener diode Z4 is connected to resistor R17, and the other end of resistor R17 is connected to pin 2 of input connector P1. Resistor R16 is connected to the positive terminal of Zener diode Z4, and the other end of resistor R16 is connected to the base of transistor Q5. The emitter of transistor Q5 is connected to pin 2 of input connector P1. The collector of transistor Q5 is connected to resistor R14, and the other end of resistor R14 is connected to the negative terminal of Zener diode Z1 in the power conversion circuit. Capacitor C9 is connected to the collector of transistor Q5, and the other end of capacitor C9 is connected to pin 2 of input connector P1. Resistor R15 is connected in parallel with capacitor C9. The base of transistor Q4 is connected to the collector of transistor Q5, and the emitter of transistor Q4 is connected to pin 2 of input connector P1. The collector of transistor Q4 is connected to resistor R13, and the other end of resistor R13 is connected to the negative terminal of the source of optocoupler U2 in the self-holding circuit.The overcurrent and short-circuit drive circuit includes a resettable fuse RF1, a resistor RC1, and a transistor Q2. One end of the resettable fuse RF1 is connected to pin 1 of the input connector P1, and the other end is connected to the resistor RC1. The other end of the resistor RC1 is connected to the base of the transistor Q2. The emitter of the transistor Q2 is connected to pin 1 of the input connector P1, and the collector of the transistor Q2 is connected to the resistor R1 in the self-holding circuit. The module switching circuit includes resistors R6 and R9, a Zener diode Z2, and a... The circuit consists of capacitor C4 and MOSFET Q1. Resistor R6 is connected at one end to the base of MOSFET Q2 in the overcurrent and short-circuit drive circuit. The other end of resistor R6 is connected to resistor R9, and the other end of resistor R9 is connected to pin 2 of input connector P1 and pin 2 of output connector P2. The cathode of Zener diode Z2 is connected to the source of MOSFET Q1, and the anode of Zener diode Z2 is connected to the gate of MOSFET Q1. Capacitor C4 is connected in parallel with the gate and source of MOSFET Q1. The drain of MOSFET Q1 is connected to pin 1 of output connector P2.

[0006] The DC self-holding electronic switch described above uses NPN transistors for transistors Q4 to Q5 in its undervoltage drive circuit.

[0007] The aforementioned DC self-holding electronic switch uses a PNP transistor in its overcurrent and short-circuit drive circuit for transistor Q2.

[0008] The aforementioned DC self-holding electronic switch uses a P-channel enhancement-type MOSFET as the MOSFET Q1 in its module switching circuit.

[0009] The basic function of this electronic switch is as follows: after the electronic switch is connected to the battery pack, when the battery pack voltage is normal, there is no output overcurrent, and there is no short circuit on the output side, the electronic switch is turned on; when the battery pack experiences undervoltage, output overcurrent, or output short circuit, the electronic switch is turned off; after the battery undervoltage, output overcurrent, and output short circuit fault conditions are resolved, the electronic switch can be turned on again upon power-on. This invention features simple circuitry, high reliability, low self-power consumption, small size, light weight, and low cost, and can be used for small lithium primary batteries.

[0010] The advantages and positive effects of this invention are as follows:

[0011] 1. The present invention has low driving signal power and a wide driving voltage range;

[0012] 2. The circuit structure of this invention is simple, small in size and light in weight, and easy to install;

[0013] 3. This invention uses mature industrial components such as resistors, capacitors, diodes, MOSFETs, and optocouplers, resulting in low cost and high reliability. Attached Figure Description

[0014] Figure 1 is a schematic diagram of the external structure of the present invention;

[0015] Figure 2 is a schematic diagram of the power conversion circuit of the present invention;

[0016] Figure 3 is a schematic diagram of the self-holding circuit of the present invention;

[0017] Figure 4 is a schematic diagram of the undervoltage drive circuit of the present invention;

[0018] Figure 5 is a schematic diagram of the overcurrent and short-circuit drive circuit, module switch circuit and input connector of the present invention. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings.

[0020] Referring to Figure 1, this invention discloses a DC self-holding electronic switch with undervoltage, overcurrent, and short-circuit protection functions, including a power conversion circuit, a self-holding circuit, an undervoltage drive circuit, an overcurrent and short-circuit drive circuit, a modular switching circuit, and two interfaces: an input connector P1 and an output connector P2. Both P1 and P2 are four-pin connectors, where pins 1 and 3 of the input connector P1 are positive inputs, and pins 2 and 4 are negative inputs; pins 1 and 3 of the output connector P2 are positive outputs, and pins 2 and 4 are negative outputs.

[0021] Referring to Figure 2, the power conversion circuit includes a diode D4, a resistor R5, a capacitor C3, and a Zener diode Z1. The positive terminal of the diode D4 is connected to pin 1 of the input connector P1, the negative terminal of the diode D4 is connected to the resistor R5, the other end of the resistor R5 is connected to the negative terminal of the Zener diode Z1, the positive terminal of the Zener diode Z1 is connected to pin 2 of the input connector P1, and the capacitor C3 is connected in parallel with the Zener diode Z1.

[0022] Referring to Figure 3, the self-holding circuit includes resistor R1, capacitor C1, optocoupler U1, resistor R2, optocoupler U2, resistor R3, capacitor C2, optocoupler U3, optocoupler U4, and resistor R4. One end of resistor R1 is connected to the collector of transistor Q2 in the overcurrent and short-circuit drive circuit, and the other end is connected to the positive source terminal of optocoupler U1. The negative source terminal of optocoupler U1 is connected to pin 2 of input connector P1. Capacitor C1 is connected in parallel with the positive and negative source terminals of optocoupler U1. One end of resistor R2 is connected to the negative terminal of Zener diode Z1 in the power conversion circuit, and the other end of resistor R2 is connected to the positive source terminal of optocoupler U2. The negative source terminal of optocoupler U2 is connected to resistor R13 in the undervoltage drive circuit. Resistor R3 is connected in parallel with the positive and negative source terminals of capacitor C2 and optocoupler U3. The secondary terminals of optocouplers U1, U2, and U3 are connected in parallel, with the positive terminal of the secondary terminal connected to the negative terminal of the Zener diode Z1 in the power conversion circuit. The negative terminal of the secondary terminal is connected to the positive terminal of the source terminal of optocoupler U3. The negative terminal of the source terminal of optocoupler U3 is connected to the positive terminal of the source terminal of optocoupler U4. The negative terminal of the source terminal of optocoupler U4 is connected to resistor R4. The other end of resistor R4 is connected to pin 2 of input connector P1. The positive terminal of the secondary terminal of optocoupler U4 is connected to the source of MOSFET Q1 in the module switching circuit, and the negative terminal of the secondary terminal of optocoupler U4 is connected to the gate of MOSFET Q1 in the module switching circuit.

[0023] Referring to Figure 4, the undervoltage drive circuit includes a Zener diode Z4, resistors R17 and R16, a transistor Q5, a resistor R14, a capacitor C9, a resistor R15, a transistor Q4, and a resistor R13. The negative terminal of Zener diode Z4 is connected to pin 1 of input connector P1. The positive terminal of Zener diode Z4 is connected to resistor R17. The other end of resistor R17 is connected to pin 2 of input connector P1. Resistor R16 is connected to the positive terminal of Zener diode Z4. The other end of resistor R16 is connected to the base of transistor Q5. The emitter of transistor Q5 is connected to pin 2 of input connector P1. The collector of transistor Q5 is connected to resistor R14. The other end of resistor R14 is connected to the negative terminal of Zener diode Z1 in the power conversion circuit. Capacitor C9 is connected to the collector of transistor Q5. The other end is connected to pin 2 of input connector P1. Resistor R15 is connected in parallel with capacitor C9. The base of transistor Q4 is connected to the collector of transistor Q5. The emitter of transistor Q4 is connected to pin 2 of input connector P1. The collector of transistor Q4 is connected to resistor R13. The other end of resistor R13 is connected to the negative source terminal of optocoupler U2 in the self-holding circuit.

[0024] Referring to Figure 5, the overcurrent and short-circuit drive circuit includes a resettable fuse RF1, a resistor RC1, and a transistor Q2. One end of the resettable fuse RF1 is connected to pin 1 of the input connector P1, and the other end is connected to the resistor RC1. The other end of the resistor RC1 is connected to the base of the transistor Q2. The emitter of the transistor Q2 is connected to pin 1 of the input connector P1, and the collector of the transistor Q2 is connected to the resistor R1 in the self-holding circuit.

[0025] The module switching circuit includes resistor R6, resistor R9, Zener diode Z2, capacitor C4, and MOSFET Q1. One end of resistor R6 is connected to the base of transistor Q2 in the overcurrent and short-circuit drive circuit, and the other end of resistor R6 is connected to resistor R9. The other end of resistor R9 is connected to pin 2 of input connector P1 and pin 2 of output connector P2. The negative terminal of Zener diode Z2 is connected to the source of MOSFET Q1, and the positive terminal of Zener diode Z2 is connected to the gate of MOSFET Q1. Capacitor C4 is connected in parallel with the gate and source of the MOSFET. The drain of MOSFET Q1 is connected to pin 1 of output connector P2.

[0026] Furthermore, transistors Q4 and Q5 in the undervoltage drive circuit are NPN transistors; transistor Q2 in the overcurrent and short-circuit drive circuit is a PNP transistor; and MOSFET Q1 in the module switching circuit is a P-channel enhancement-type MOSFET.

[0027] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A DC self-holding electronic switch, characterized in that: The circuit includes a power conversion circuit, a self-holding circuit, an undervoltage drive circuit, an overcurrent and short-circuit drive circuit, a module switch circuit, an input connector P1, and an output connector P2. The power conversion circuit includes a diode D4, a resistor R5, a capacitor C3, and a Zener diode Z1. The anode of diode D4 is connected to pin 1 of input connector P1, the cathode of diode D4 is connected to resistor R5, the other end of resistor R5 is connected to the cathode of Zener diode Z1, and the anode of Zener diode Z1 is connected to pin 2 of input connector P1. Capacitor C3 is connected in parallel with Zener diode Z1. The self-holding circuit includes resistors R1-R4, capacitors C1-C2, and optocouplers U1-U4. One end of resistor R1 is connected to the collector of transistor Q2, and the other end is connected to the optocoupler U1-U4. The positive terminal of optocoupler U1 and the negative terminal of optocoupler U1 are connected to pin 2 of input connector P1. Capacitor C1 is connected in parallel with the positive and negative terminals of the optocoupler U1's source. One end of resistor R2 is connected to the negative terminal of Zener diode Z1, and the other end of resistor R2 is connected to the positive terminal of the optocoupler U2's source. The negative terminal of the optocoupler U2's source is connected to resistor R13. Resistor R3 is connected in parallel with capacitor C2 and the positive and negative terminals of the optocoupler U3's source. The secondary terminals of optocouplers U1-U3 are connected in parallel, with the positive terminal of the secondary terminal connected to the negative terminal of Zener diode Z1. The negative terminal of the secondary terminal is connected to the positive terminal of the optocoupler U3's source. The negative terminal of the optocoupler U3's source is connected to the positive terminal of the optocoupler U4's source. The negative terminal of the optocoupler U4's source is connected to resistor R4, and the other end of resistor R4 is connected to pin 2 of input connector P1. The positive terminal of the secondary terminal of optocoupler U4 is connected to a MOSFET. The source of Q1 and the negative terminal of the secondary side of optocoupler U4 are connected to the gate of MOSFET Q1. The undervoltage drive circuit includes Zener diode Z4, transistors Q4-Q5, capacitor C9, and resistors R13-R17. The negative terminal of Zener diode Z4 is connected to pin 1 of input connector P1, the positive terminal of Zener diode Z4 is connected to resistor R17, the other end of resistor R17 is connected to pin 2 of input connector P1, resistor R16 is connected to the positive terminal of Zener diode Z4, the other end of resistor R16 is connected to the base of transistor Q5, the emitter of transistor Q5 is connected to pin 2 of input connector P1, the collector of transistor Q5 is connected to resistor R14, the other end of resistor R14 is connected to the negative terminal of Zener diode Z1, and capacitor C9 is connected to the collector of transistor Q5. The other end of capacitor C9 is connected to pin 2 of input connector P1. Resistor R15 is connected in parallel with capacitor C9. The base of transistor Q4 is connected to the collector of transistor Q5. The emitter of transistor Q4 is connected to pin 2 of input connector P1. The collector of transistor Q4 is connected to resistor R13. The other end of resistor R13 is connected to the negative terminal of the source of optocoupler U2. The overcurrent and short-circuit drive circuit includes a resettable fuse RF1, a resistor RC1 and a transistor Q2. One end of the resettable fuse RF1 is connected to pin 1 of input connector P1, and the other end is connected to resistor RC1. The other end of resistor RC1 is connected to the base of transistor Q2. The emitter of transistor Q2 is connected to pin 1 of input connector P1. The collector of transistor Q2 is connected to resistor R1.The module switching circuit includes resistor R6, resistor R9, Zener diode Z2, capacitor C4, and MOSFET Q1. One end of resistor R6 is connected to the base of MOSFET Q2, and the other end of resistor R6 is connected to resistor R9. The other end of resistor R9 is connected to pin 2 of input connector P1 and pin 2 of output connector P2. The cathode of Zener diode Z2 is connected to the source of MOSFET Q1, and the anode of Zener diode Z2 is connected to the gate of MOSFET Q1. Capacitor C4 is connected in parallel with the gate and source of MOSFET Q1. The drain of MOSFET Q1 is connected to pin 1 of output connector P2.

2. The DC self-holding electronic switch according to claim 1, characterized in that, The transistors Q4 to Q5 are NPN transistors.

3. A DC self-holding electronic switch according to claim 1, characterized in that, The transistor Q2 mentioned above is a PNP transistor.

4. A DC self-holding electronic switch according to claim 1, characterized in that, The MOSFET Q1 mentioned above is a P-channel enhancement-mode MOSFET.

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