Short-circuit protection circuit of general gasoline engine voltage regulator

Abstract

The short-circuit protection circuit comprises a time delay circuit, a bootstrap circuit, an anode switch circuit and a cathode switch circuit, the output anode of the voltage regulator is connected with the anode of the load through the anode switch circuit; the output negative electrode of the voltage regulator is connected with the grounding end GND of the load through the negative electrode switch circuit. The positive pole switch circuit is used for electrically connecting / disconnecting an output positive pole of the voltage regulator and a ground terminal GND; the delay circuit is used for controlling the positive pole switch circuit to be switched on when the rotating speed of the motor is lower than a set value; the bootstrap circuit is electrically connected between the output positive electrode of the voltage regulator and the first control end of the positive electrode switching circuit, and the bootstrap circuit is used for controlling the positive electrode switching circuit to keep a conducting state; and when the positive pole switch circuit is in a conducting state, the negative pole switch is used for controlling the output negative pole of the voltage regulator to be connected with the ground terminal GND. The circuit is simple, uses few devices, has strong compatibility, can be used on various general gasoline engine voltage regulators with different current outputs, and can avoid higher loss caused by short circuit due to misoperation.

Description

Technical Field

[0001] The utility model relates to the field of general-purpose engine voltage regulators, and particularly relates to a short-circuit protection circuit for a general-purpose engine voltage regulator. Background Art

[0002] Traditional general-purpose engine voltage regulators do not have short-circuit protection functions. The output current of a general-purpose engine voltage regulator is related to the output power of the coil. The greater the output power of the coil, the greater the current of the general-purpose engine voltage regulator. When a short-circuit occurs, the coil will output a large current through the general-purpose engine voltage regulator. Whether in production testing or in the operation of assembling the whole machine, it is very easy to burn out the coil and the voltage regulator. And when the general-purpose engine voltage regulator is short-circuited, the voltage of the coil will be pulled down very low, making it difficult to obtain a voltage to control the turn-off of the voltage regulator. Generally, a short-circuit protection circuit is of a repeated impact type. If the output current of the general-purpose engine voltage regulator itself is very large, this kind of short-circuit protection cannot achieve good results. The coil and the voltage regulator still have a large load after short-circuit, and there is a risk of burning out. Therefore, in order to solve the above problems, a short-circuit protection circuit for a general-purpose engine voltage regulator is needed. Summary of the Utility Model

[0003] Aiming at the deficiencies of the prior art, the utility model provides a short-circuit protection circuit for a general-purpose engine voltage regulator, and the specific technical solutions are as follows:

[0004] A short-circuit protection circuit for a general-purpose engine voltage regulator, characterized in that:

[0005] It includes a delay circuit, a bootstrap circuit, a positive pole switch circuit and a negative pole switch circuit;

[0006] The positive output pole of the voltage regulator is connected to the positive pole of the load through the positive pole switch circuit;

[0007] The negative output pole of the voltage regulator is connected to the ground terminal GND of the load through the negative pole switch circuit;

[0008] The positive pole switch circuit is used to electrically connect / disconnect the positive output pole of the voltage regulator from the ground terminal GND;

[0009] The delay circuit is used to control the conduction of the positive pole switch circuit when the motor speed is lower than the set value;

[0010] The bootstrap circuit is electrically connected between the positive output pole of the voltage regulator and the first control end of the positive pole switch circuit, and the bootstrap circuit is used to control the positive pole switch circuit to maintain the conduction state;

[0011] When the positive pole switch circuit is in the conduction state, the negative pole switch is used to control the connection of the negative output pole of the voltage regulator to the ground terminal GND.

[0012] To better implement the present utility model, it can be further provided that: the negative pole switch circuit includes a relay JK1, the output positive pole is connected to the first coil port of the relay JK1, and the second coil port of the relay JK1 is connected to the ground terminal GND;

[0013] The output negative pole is connected to the first end of the normally open port of the relay JK1, and the second end of the normally open port of the relay JK1 is connected to the first output end.

[0014] Furthermore: the positive pole switch circuit has a first input end, a first output end, and a first control end;

[0015] The first control end is used to control the electrical connection / disconnection between the first input end and the first output end.

[0016] Furthermore: the positive pole switch circuit includes a MOS transistor Q3, a resistor R18, a resistor R19, and an optocoupler U1;

[0017] The drain of the MOS transistor Q3 is the input end of the positive pole switch circuit, the gate of the MOS transistor Q3 is connected to the anode of the optocoupler U1 through the resistor R19, the cathode of the optocoupler U1 is connected to the ground terminal GND, and the cathode of the optocoupler U1 is the output end of the positive pole switch circuit.

[0018] Furthermore: the delay circuit includes a diode D7, the negative pole of the diode D7 is connected to the first end of the resistor R23 through a resistor R24, and the second end of the resistor R24 is the output end of the delay circuit;

[0019] The source of the MOS transistor Q4 is connected between the resistor R23 and the resistor R24, and the drain of the MOS transistor Q4 is connected to the ground terminal GND;

[0020] The gate of the MOS transistor Q4 is connected to the negative pole of a diode D9 through a resistor R27, and the positive pole of the diode D9 is connected between the negative pole of the diode D7 and the resistor R24 through resistors R26 and R25;

[0021] The cathode of a voltage stabilizing diode ZD4 is connected to the common end of the resistors R25 and R26, and the anode of the voltage stabilizing diode ZD4 is connected to the ground terminal.

[0022] Further: The bootstrap circuit includes a diode D10 and a resistor R20. The positive electrode of the diode D10 is connected to the positive output terminal. The negative electrode of the diode D10 is connected to the first end of the resistor R20. The second end of the resistor R20 is connected to the control terminal of the positive electrode switch circuit. The anode of the diode D10 is the input terminal of the bootstrap circuit, and the second end of the resistor R20 is the output terminal of the bootstrap circuit. The beneficial effects of the present utility model are as follows: The overall structure is simple. The protection circuit of the present utility model is connected to the general-purpose machine voltage regulator. Although the short-circuit protection circuit has four parts, the circuit is simple and uses few components, with strong compatibility. It can be used on various general-purpose machine voltage regulators with different current outputs, and can avoid high losses caused by short circuits due to operating errors. The invention circuit of the present utility model includes a delay circuit, a bootstrap circuit, a positive electrode switch circuit, and a negative electrode switch circuit. By designing the delay circuit to work and turn on the positive electrode switch circuit, then the bootstrap circuit works, the delay circuit turns off, and then the negative electrode switch circuit is turned on. These four parts of the circuit in this working process form the short-circuit protection circuit of the general-purpose machine voltage regulator. When a short-circuit anomaly occurs, the negative electrode switch circuit and the positive electrode switch circuit are turned off, and the general-purpose machine voltage regulator will not have an output externally, so the short circuit will not affect the coil and the voltage regulator until the motor is restarted after troubleshooting, and it will not cause the situation of burning out the voltage regulator coil and the load connected to the voltage regulator due to short circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the overall structure diagram of the present utility model;

[0024] Figure 2 is the application structure diagram of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present utility model.

[0026] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "vertical", "upper", "lower", "horizontal", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. In addition, "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] Such asFigure 1 and Figure 2 as shown in

[0028] A short - circuit protection circuit for a general - purpose machine voltage regulator, including a delay circuit, a bootstrap circuit, a positive - pole switch circuit, and a negative - pole switch circuit;

[0029] The positive output of the voltage regulator is connected to the positive pole of the load through the positive - pole switch circuit;

[0030] The negative output of the voltage regulator is connected to the ground terminal GND of the load through the negative - pole switch circuit.

[0031] The positive - pole switch circuit is used to electrically connect / disconnect the positive output of the voltage regulator and the ground terminal GND;

[0032] The delay circuit is used to control the positive - pole switch circuit to conduct when the motor speed is lower than the set value. Specifically, in this embodiment, the set value is 500 r / min. When the motor speed is higher than 500 r / min, the delay circuit stops outputting.

[0033] The bootstrap circuit is electrically connected between the positive output of the voltage regulator and the first control terminal, and the bootstrap circuit is used to control the positive - pole switch circuit to maintain the conducting state;

[0034] When the positive - pole switch circuit is in the conducting state, the negative - pole switch is used to control the negative output of the voltage regulator to be connected to the ground terminal GND.

[0035] The delay circuit has a voltage output terminal, and the positive - pole switch circuit has a control terminal, and this control terminal is used to control the closing of the positive - pole switch circuit.

[0036] When the generator starts, the voltage output terminal of the delay circuit is used to provide a control voltage to the positive - pole switch circuit. The positive - pole switch circuit is electrically connected between the positive output of the generator and the ground terminal. The control voltage is used to control the positive - pole switch circuit. The closing of the positive - pole switch circuit causes a closed loop to be formed between the positive output, the positive - pole switch circuit, and the ground terminal. The bootstrap circuit is electrically connected between the positive output and the control terminal of the positive - pole switch circuit. The positive output is connected to the first control terminal of the relay, and the second control terminal of the relay is grounded.

[0037] A negative - pole switch circuit is electrically connected between the positive output and the negative output. The negative - pole switch circuit includes a relay JK1. The negative output is connected to the first end of the normally - open port of the relay, and the second end of the normally - open port is connected to the output end of the positive - pole switch circuit.

[0038] The delay circuit includes a diode D7. The negative pole of the diode D7 is connected to the first end of a resistor R23 through a resistor R24, and the second end of the resistor R24 is the output terminal of the delay circuit.

[0039] The source of MOS transistor Q4 is connected between resistor R23 and resistor R24. The drain of MOS transistor Q4 is connected to the ground terminal GND. The gate of this MOS transistor Q4 is connected to the negative electrode of diode D9 via resistor R27. A resistor R28 is connected across the gate and drain of MOS transistor Q4. The positive electrode of diode D9 is connected between the negative electrode of diode D7 and resistor R24 via resistor R26 and resistor R25. The cathode of voltage regulator ZD4 is connected to the common terminal of resistor R25 and resistor R26, and the anode of voltage regulator ZD4 is connected to the ground terminal. Since the motor speed is low, the output voltage of the coil is low. When the coil voltage is lower than the set value, the delay circuit will have an output. When the coil voltage is higher than the set value, there will be no output. Changing the value of R28 in the circuit can adjust the magnitude of this voltage value, that is, the magnitude of the speed. Different motors have different voltages at the same speed, and the speeds limited by the delay circuit are different.

[0040] The bootstrap circuit includes diode D10 and resistor R20. The positive electrode of diode D10 is connected to the output positive electrode. The negative electrode of this diode D10 is connected to the first end of resistor R20. The second end of this resistor R20 is connected to the control terminal of the positive electrode switch circuit. The anode of diode D10 is the input terminal of the bootstrap circuit, and the second end of resistor R20 is the output terminal of the bootstrap circuit.

[0041] The positive electrode switch circuit includes MOS transistor Q3, resistor R18, resistor R19, and optocoupler U1. The drain of MOS transistor Q3 is the input terminal of the positive electrode switch circuit. The gate of MOS transistor Q3 is connected to the positive emitter of optocoupler U1 via resistor R19. The negative emitter of optocoupler U1 is connected to the ground terminal GND. The negative emitter of optocoupler U1 is the output terminal of the positive electrode switch circuit.

[0042] The negative electrode switch circuit includes relay JK1 and resistor R22. The first coil terminal of this relay JK1 is connected to the first end of resistor R22. The second end of this resistor R22 is connected to the output positive electrode. The second coil terminal of this relay JK1 is connected to the ground terminal GND. The first normally open port of the relay is connected to the output negative electrode, and the second normally open port of the relay is connected to the output terminal of the positive electrode switch circuit.

[0043] Principle of the present utility model:

[0044] The present invention is composed of four parts: a delay circuit, a positive pole switch circuit, a bootstrap circuit, and a negative pole switch circuit. When the motor starts, the delay circuit outputs a positive voltage to drive the positive pole switch circuit and turn on the positive pole. Subsequently, the bootstrap circuit provides a continuous driving voltage for the positive pole switch circuit. After reaching a certain rotational speed, the delay circuit stops outputting. After the positive pole switch circuit is turned on, the negative pole switch circuit is driven to turn on, and the motor provides a voltage output for the voltage regulating circuit. When an abnormality such as a short circuit occurs, the negative pole switch circuit closes first, and then the positive pole switch circuit also closes, and the voltage regulator stops outputting immediately until the fault is eliminated and the motor is restarted, thereby achieving a good protection effect.

[0045] When an abnormality such as a short circuit occurs, this short circuit protection circuit can promptly and completely turn off the external output of the voltage regulator, and there will be no impact of repeated restarting. When an abnormality such as a short circuit occurs, there will be no damage due to the large output current of the voltage regulator. The four-part circuit is simple and has a good protection effect; it has strong compatibility with the output current of the voltage regulator and can be used for currents of several amperes or dozens of amperes, which can avoid accidents caused by short circuit abnormalities during production and assembly of the whole machine.

[0046] The specific circuit working process is as Figure 1 and Figure 2 shown. After the motor starts to rotate, the alternating voltage of the coil in the motor continuously increases. When the rotational speed of the motor is relatively low, the delay circuit outputs a positive voltage for driving the optocoupler U1, and the optocoupler U1 drives the MOS transistor Q3 in the positive pole switch circuit to turn on.

[0047] After the MOS transistor Q3 is turned on, the bootstrap circuit composed of the diode D10 and the resistor R20 in the output positive pole continuously provides a driving voltage for the optocoupler U1 to ensure that the MOS transistor Q3 remains turned on. After the MOS transistor Q3 is turned on, the relay JK1 of the negative pole switch circuit is driven, and the normally open switch closes, connecting the output negative pole to the external voltage, and the motor provides a voltage output for the voltage regulating circuit. When the rotational speed of the motor continues to increase, the MOS transistor Q4 in the delay circuit turns on, causing the delay circuit to stop outputting.

[0048] During a short - circuit anomaly, during operation, if the output positive terminal and the output negative terminal are suddenly short - circuited, the potentials of the output positive terminal, the output negative terminal, and the grounding terminal are the same. The relay JK1 will immediately disconnect. Since the optocoupler U1 loses drive, the MOS transistor Q3 turns off, causing the voltage - regulating circuit to stop outputting voltage until the motor stops rotating, achieving the effect of protecting the coil and some components. If the output positive terminal and the output negative terminal are short - circuited before the motor starts, the JK1 in the negative - terminal switch circuit of the motor start will not be turned on, and the MOS transistor Q3 in the positive - terminal switch circuit will also turn off. The voltage - regulating circuit has no output until the motor stops rotating, effectively protecting the motor coil and the external load. The MOS transistor Q3 is a P - type transistor, and the MOS transistor Q4 is an N - type transistor. The output negative terminal uses a relay, which has a very low additional power loss for the voltage regulator. At the same time, it can also solve the problem that when using a general - purpose generator voltage regulator to charge a lead - acid battery, the voltage regulator will consume the power of the lead - acid battery when it is not working. When the voltage regulator is not working, the negative - terminal switch separates the lead - acid battery from the general - purpose generator voltage regulator, and does not consume the battery power.

[0049] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above - mentioned exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non - restrictive. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present utility model. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0050] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A short-circuit protection circuit for a voltage regulator, characterized in that: It includes a time delay circuit, a bootstrap circuit, a positive switch circuit and a negative switch circuit; The positive output electrode of the voltage regulator is connected to the positive electrode of the load via the positive switch circuit; The negative output electrode of the voltage regulator is connected to the ground terminal GND of the load via the negative switch circuit; The positive switch circuit is used to electrically connect / disconnect the positive output electrode of the voltage regulator and the ground terminal GND; The delay circuit is used to control the positive switch circuit to conduct when the motor speed is lower than the set value; The bootstrap circuit is electrically connected between the positive output electrode of the voltage regulator and the first control terminal of the positive switch circuit, and the bootstrap circuit is used to control the positive switch circuit to maintain a conducting state; When the positive switch circuit is in the on state, the negative switch is used to control the output negative electrode of the voltage regulator to be connected to the ground terminal GND.

2. The short-circuit protection circuit of a voltage regulator according to claim 1, characterized in that: The negative electrode switch circuit includes a relay JK1, the output positive electrode is connected to the first coil port of the relay JK1, and the second coil port of the relay JK1 is connected to the ground terminal GND; The output cathode is connected to a first end of a normally open port of the relay JK1 , and a second end of the normally open port of the relay JK1 is connected to the first output end.

3. The short-circuit protection circuit of the voltage regulator according to claim 2, characterized in that: The positive switch circuit has a first input terminal, a first output terminal and a first control terminal; The first control end is used to control the electrical connection / disconnection between the first input end and the first output end.

4. The short-circuit protection circuit of the voltage regulator according to claim 3, characterized in that: The positive switch circuit includes a MOS tube Q3, a resistor R18, a resistor R19 and an optical coupler U1; The drain of the MOS tube Q3 is the input end of the positive switch circuit, the gate of the MOS tube Q3 is connected to the positive emitter of the optocoupler U1 through the resistor R19, the negative emitter of the optocoupler U1 is connected to the ground terminal GND, and the negative emitter of the optocoupler U1 is the output end of the positive switch circuit.

5. The short-circuit protection circuit of the voltage regulator according to claim 4, characterized in that: The delay circuit includes a diode D7, the cathode of which is connected to the first end of the resistor R23 via a resistor R24, and the second end of the resistor R24 ​​is the output end of the delay circuit; The source of the MOS tube Q4 is connected between the resistor R23 and the resistor R24, and the drain of the MOS tube Q4 is connected to the ground terminal GND; The gate of the MOS transistor Q4 is connected to the cathode of the diode D9 via the resistor R27, and the anode of the diode D9 is connected between the cathode of the diode D7 and the resistor R24 ​​via the resistor R26 and the resistor R25; The cathode of the voltage regulator tube ZD4 is connected to the common end of the resistor R25 and the resistor R26, and the anode of the voltage regulator tube ZD4 is connected to the ground end.

6. A short-circuit protection circuit for a voltage regulator according to claim 5, characterized in that: The bootstrap circuit includes a diode D10 and a resistor R20, wherein the positive electrode of the diode D10 is connected to the output positive electrode, the negative electrode of the diode D10 is connected to the first end of the resistor R20, the second end of the resistor R20 is connected to the control end of the positive electrode switching circuit, the anode of the diode D10 is the input end of the bootstrap circuit, and the second end of the resistor R20 is the output end of the bootstrap circuit.

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