TW202213891A - Dc short circuits protection device - Google Patents

Abstract

The DC short circuits protection device of the invention comprises a first semiconductor, a second semiconductor, a first resistor, a second resistor, a third resistor and a photocoupler, constituting an application circuit with load overload or short circuit protection function, which avoids the damage caused by overload or short circuit at both terminals of the load.

Description

DC short circuit protection device

The DC short-circuit protection device of the present invention has the protection function of overload or short-circuit at both ends of the load during the application of the DC circuit, and includes a first semiconductor, a second semiconductor, a first resistor, a second resistor, and a third resistor. And the field of electronic technology of optocoupler.

Please refer to Taiwan Patent Certificate No. Invention No. I 583089 “Battery Discharge Protection Device”. As shown in FIG. 1 , when the charging device 100 performs the charging operation on the battery 11 , the positive terminal G+ of the charging device 100 supplies a positive voltage to the first The collector resistor 15 is connected to the gate terminal G of the first semiconductor 12. At this time, the source S and drain D of the first semiconductor 12 are turned on, and the charging current passes through the positive terminal of the battery 11, the negative terminal of the battery 11, and the first semiconductor. The source S of the 12 and the drain D of the first semiconductor 12 return to the negative terminal G- of the charging device 100 to achieve the charging operation of the battery 11 .

As shown in FIG. 1 , when the charging operation is completed, the charging device 100 is changed to a load 200, and the battery 11 performs a discharging operation on the load 200. At this time, the positive terminal of the battery 11 supplies a positive voltage to the first collector resistor 15 to the second The gate G of a semiconductor 12, so the source S and drain D of the first semiconductor 12 are turned on, and the discharge current flows through the load 200 The positive terminal of the load 200 is the negative terminal of the load 200 , the drain D of the first semiconductor 12 , the source S of the first semiconductor 12 , and return to the negative terminal of the battery 11 to achieve the discharge operation of the battery 11 .

As shown in FIG. 1 , when the load 200 is short-circuited during the discharge operation of the battery 11 to the load 200, the potential of the base B of the second semiconductor 14 is the circuit positive potential, so the potential of the base B of the second semiconductor 14 is higher than The emitter E turns on the second semiconductor 14. At this time, the potentials of the gate G and the source S of the first semiconductor 12 are equal, so the first semiconductor 12 is opened, and the drain current of the first semiconductor 12 is stopped at this time to protect the The battery 11 is damaged due to the short circuit of the load 200. If you want to release the conduction state of the second semiconductor 14, you only need to remove the cause of the short circuit, the conduction state of the second semiconductor 14 can be released, and the normal state of the first semiconductor 12 can be restored. status, its disadvantages are as follows:

1. After removing the cause of the short circuit at both ends of the load 200, a switch should be set to open the load 200 (Off), and then the switch should be turned on (On) before the battery 11 can supply power to the load 200 again, thus increasing the cost of the device and application inconvenience.

2. To restore the normal circuit function, after removing the cause of the short circuit between the two ends of the load 200, and then re-powering the battery 11, a switch must be added, which increases the cost of the device and causes inconvenience in application.

Purpose of the present invention:

The present invention applies the first semiconductor, the second semiconductor, the first resistor, the second resistor, the third resistor and the optocoupler, so that the DC power supply can be protected when the load is overloaded or short-circuited in the DC circuit power supply.

When the load is short-circuited, the present invention uses the second semiconductor to The first semiconductor open-circuit action is performed in a short time to achieve the function of protecting the DC power supply circuit and avoid various disasters caused by short-circuit of the load.

When the photocoupler of the present invention implements the present invention, the second semiconductor performs a delay action when the power is turned on. When the cause of the short circuit is eliminated, it is not necessary to re-supply the DC power supply and it is not necessary to remove the cause of the short circuit at both ends of the load, and a switch is required to perform the action of opening and conducting.

The present invention has the following features:

1. The first semiconductor of the present invention is responsible for the open circuit and conduction of the DC power supply to supply power to the load.

2. The second semiconductor of the present invention is responsible for controlling the open-circuit and conduction actions of the first semiconductor, so as to achieve the purpose of protecting the DC power supply circuit when a short circuit occurs at both ends of the load.

3. In the present invention, the first resistor has the function of limiting current to prevent the first semiconductor from being damaged due to excessive gate or base current.

4. The present invention is provided with a second resistor which has the function of limiting current, so as to prevent the photocoupler from being damaged by excessive current generated in the light emitting diode of the photocoupler.

5. In the present invention, the third resistor has the function of limiting the current, so as to prevent the second semiconductor from being damaged due to excessive gate or base current.

6. The optocoupler of the present invention is responsible for controlling the open-circuit and conduction time of the second semiconductor, so as to achieve the purpose of initiating the conduction of the first semiconductor.

7. The first semiconductor of the present invention includes an N Channel Metal Oxide Semiconductor Field Effect Transistor (N Channel MOSFET), an N Type Transistor or an Insulated Gate Bipolar Transistor (Insulated Gate Bipolar Transistor, IGBT) can be selected according to the needs.

8. The second semiconductor of the present invention includes an N-channel metal oxide semiconductor field effect transistor, an N-type transistor or an insulated gate bipolar transistor, which can be selected according to requirements.

9. The optocoupler of the present invention includes Transistor Output, Darlington Phototransistor Output or Potorelays, which can be selected according to requirements.

10: DC power supply

11: The first switch

12: Load

13: Second switch

20: DC short-circuit protection device of the present invention

21: First resistor

22: Second resistor

23: Third resistor

24: Photocoupler

25: First Semiconductor

26: Second Semiconductor

27: Ground terminal

30: The first terminal

40: The second terminal

50: The third terminal

FIG. 1 is an embodiment of a conventional battery discharge protection device.

FIG. 2 is the first embodiment of the DC short-circuit protection device of the present invention.

FIG. 3 is a second embodiment of the DC short-circuit protection device of the present invention.

FIG. 4 is a third embodiment of the DC short-circuit protection device of the present invention.

FIG. 5 is a fourth embodiment of the DC short circuit protection device of the present invention.

FIG. 6 is a fifth embodiment of the DC short-circuit protection device of the present invention.

As shown in FIG. 2 , it is the first embodiment of the DC short-circuit protection device of the present invention. As can be seen from the figure, the DC power supply 10 is connected to the first switch 11 , the first switch 11 is connected to the first end of the load 12 , and the second end of the load 12 Connect the second terminal 40 , the drain D (Drain, D) of the first semiconductor 25 and the first end of the third resistor 23 , and the second end of the third resistor 23 is connected to the first end T1 of the optocoupler 24 , the second end T2 of the photocoupler 24 is connected to the base B of the second semiconductor 26; the DC power supply 10 is connected to the first end of the second switch 13, and the second end of the second switch 13 is connected to the first terminal 30 and the first terminal Resistor The first end of 21, the second end of the first resistor 21 is connected to the gate G (Gate, G) of the first semiconductor 25 and the collector C (Collector, C) of the second semiconductor 26; the DC power supply 10 is connected to the second The first terminal of the switch 13 and the second terminal of the second switch 13 are connected to the first terminal 30 and the first terminal of the second resistor 22 , and the second terminal of the second resistor 22 is connected to the anode terminal A of the photocoupler 24 (Anode, A); the DC power supply 10, the first switch 11 and the load 12 form a series connection circuit;

The DC power source 10 , the second switch 13 and the first resistor 21 form a series connection circuit; the DC power source 10 , the second switch 21 and the second resistor 22 form a series connection circuit; the first end of the first switch 11 The first terminal of the second switch 13 is connected to the positive terminal of the DC power supply 10, and the negative terminal of the DC power supply 10 is connected to the third terminal 50 and the ground terminal 27; The power supply, one is the first DC power supply connected to the first switch 11, and the other is the second DC power supply connected to the second switch 13, which is not self-limited; the second DC power supply can be regarded as a voltage source, not The self-limiting is the second DC power source, that is, the second DC power source can be replaced by a pulse power source, and its operating principle and function are the same as using the second DC power source.

As shown in FIG. 2, the DC short-circuit protection device 20 of the present invention includes a first semiconductor 25, a second semiconductor 26, a first resistor 21, a second resistor 22, a third resistor 23 and an optocoupler 24; the first The drain D of the semiconductor 25 and the first end of the third resistor 23 are connected to the second terminal 40 and the second end of the load 12 , the gate G of the first semiconductor 25 , the collector C of the second semiconductor 26 and the first The second ends of the resistors 21 are connected together; the anode end A of the photocoupler 24 is connected to the second end of the second resistor 22 , the cathode end K (Cathode, K) of the photocoupler 24 , and the source of the first semiconductor 25 The pole S (Source, S) is connected to the emitter E (Emitter, E) of the second semiconductor 26 Connected together to form a ground terminal 27, the ground terminal 27 is connected to the negative terminal of the DC power supply 10, the first terminal T1 of the optocoupler 24 is connected to the second terminal of the third resistor 23, and the second terminal T2 of the optocoupler 24 is connected The base B (Base, B) of the second semiconductor 26; the first semiconductor 25 is an N-channel metal-oxide-semiconductor field effect transistor, the second semiconductor 26 is an N-type transistor, and the photocoupler 24 can also be a transistor output type The Darlington composite transistor output type or photorelay is used, because its action principle and function are the same as the transistor output type, and the selection is not limited according to its needs.

As shown in Figure 2, the operating principle of the DC short-circuit protection device of the present invention is as follows:

As shown in FIG. 2 , when the first switch 11 is turned on, the current of the DC power supply 10 passes through the first switch 11 and the load 12 , and then passes through the second terminal 40 to the drain D of the first semiconductor 25 and the third resistor 23 The first end of the third resistor 23 and the second end of the third resistor 23 go to the first end T1 of the photocoupler 24. At this time, the gate G of the first semiconductor 25 has no gate G voltage, so the drain of the first semiconductor 25 D and the source S are open-circuited. At the same time, since the anode terminal A of the photocoupler 24 has no voltage supply, the first terminal T1 and the second terminal T2 of the photocoupler 24 are open-circuited. Since the drain D and the source of the first semiconductor 25 S is open, and the first terminal T1 and the second terminal T2 of the photocoupler 24 are open, so the load 12 is not supplied with the DC power supply 10; when the second switch 13 is turned on, the current from the DC power supply 10 passes through the first terminal. 30, and then the first resistor 21 supplies power to the gate G of the first semiconductor 25, so the drain D of the first semiconductor 25 is connected to the source S. At this time, the DC power supply 10 supplies power to the load 12 and passes through the second resistor. The switch 22 supplies power to the anode terminal A of the optocoupler 24, so the first terminal T1 and the second terminal T2 of the optocoupler 24 are conductive; when the second switch 13 is open, the The gate G of the semiconductor 25, so the drain D and the source S of the first semiconductor 25 are open-circuited. At this time, the DC power supply 10 does not supply power to the load 12, and does not supply power to the anode terminal A of the photocoupler 24. Therefore, the photocoupler 24 has an open circuit between the first terminal T1 and the second terminal T2.

As shown in FIG. 2 , the short-circuit protection action principle of the load 12 of the DC short-circuit protection device of the present invention is as follows:

It can be seen from the above that when the first switch 11 and the second switch 13 are turned on, the load 12 is powered by the DC power supply 10; when both ends of the load 12 are short-circuited, according to the output characteristics of the first semiconductor 25, when The drain current (Drain Current) of the first semiconductor 25 rises to its corresponding drain source voltage (Drain Source Voltage) reaching higher than the turn-on voltage ( On State Voltage), the drain-source voltage of the first semiconductor 25 supplies power to the base B of the second semiconductor 26. At this time, the collector C and the emitter E of the second semiconductor 26 are turned on, so the drain of the first semiconductor 25 D and the source S are open-circuited, the DC power supply 10 does not supply power to the short-circuit load 12, and the DC power supply 10 is protected; similarly, the conduction voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24 is appropriately selected , the overload protection function can also be achieved in accordance with the overload (Over Load) sink current required by the first semiconductor 25 .

As shown in FIG. 3, it is the second embodiment of the DC short circuit protection device of the present invention. It can be seen from the figure that the first semiconductor 25 in FIG. 2 is changed from an N-channel metal oxide semiconductor field effect transistor to an N-type semiconductor. The coupler 24 adopts the transistor output type, and can also use the Darlington compound transistor output type or the photorelay, because its operation principle and function are the same as those of the transistor output type, and other circuit structures are the same as those of FIG. 2 and will not be repeated.

As shown in Figure 3, the operating principle of the DC short-circuit protection device of the present invention as follows:

As shown in FIG. 3 , when the first switch 11 is turned on, the current of the DC power source 10 passes through the first switch 11 and the load 12 , and then passes through the second terminal 40 to the collector C of the first semiconductor 25 and the third resistor 23 The first end of the third resistor 23 and the second end of the third resistor 23 go to the first end T1 of the photocoupler 24. At this time, the base B of the first semiconductor 25 has no base B voltage, so the collector of the first semiconductor 25 C and the emitter E are open-circuited. At the same time, because the anode terminal A of the photocoupler 24 has no voltage supply, the first terminal T1 and the second terminal T2 of the photocoupler 24 are open-circuited. Since the collector C and the emitter of the first semiconductor 25 E is open, and the first terminal T1 and the second terminal T2 of the photocoupler 24 are open, so the load 12 is not supplied by the DC power supply 10; when the second switch 13 is turned on, the current from the DC power supply 10 passes through the first terminal. 30, and then the first resistor 21 supplies power to the base B of the first semiconductor 25, so the collector C of the first semiconductor 25 is connected to the emitter E. At this time, the DC power supply 10 supplies power to the load 12 and passes through the second resistor. The switch 22 supplies power to the anode terminal A of the optocoupler 24, so the first terminal T1 and the second terminal T2 of the optocoupler 24 are conductive; when the second switch 13 is open, the base of the first semiconductor 25 is not powered. Therefore, the collector C and the emitter E of the first semiconductor 25 are open-circuited. At this time, the DC power supply 10 does not supply power to the load 12, and does not supply power to the anode terminal A of the photocoupler 24. Therefore, the first There is an open circuit between the terminal T1 and the second terminal T2.

As shown in FIG. 3 , the short-circuit protection action principle of the load 12 of the DC short-circuit protection device of the present invention is as follows:

It can be seen from the above that when the first switch 11 and the second switch 13 are turned on, the load 12 is powered by the DC power supply 10; when both ends of the load 12 are short-circuited, according to the output characteristic curve table of the first semiconductor 25, when the first semiconductor 25 the collector current rises to its corresponding When the collector-emitter voltage reaches higher than the turn-on voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24, the collector-emitter voltage of the first semiconductor 25 supplies power to the base B of the second semiconductor 26, at this time The collector C and the emitter E of the second semiconductor 26 are conductive, so the collector C and the emitter E of the first semiconductor 25 are open-circuited, the DC power supply 10 does not supply power to the short-circuit load 12, and the DC power supply 10 is protected; similarly, The on-voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24 is appropriately selected, and the overload protection function can also be achieved in accordance with the overload collector current required by the first semiconductor 25 .

It can be seen from the above that changing the first semiconductor 25 of FIG. 2 from an N-channel metal oxide semiconductor field effect transistor to an N-type semiconductor has the same operating principle and the same function of protecting the DC power supply 10 when the load 12 is short-circuited.

As shown in FIG. 4, it is the third embodiment of the DC short-circuit protection device of the present invention. As can be seen from the figure, the second semiconductor 26 in FIG. 2 is changed from an N-type semiconductor to an N-channel metal oxide semiconductor field effect transistor. The coupler 24 is a transistor output type, and can also be a Darlington composite transistor output type or a photorelay, because its operating principle and function are the same as those of the transistor output type, and other circuit structures are the same as in FIG. 2 and will not be repeated.

As shown in Figure 4, the operating principle of the DC short-circuit protection device of the present invention is as follows:

As shown in FIG. 4 , when the first switch 11 is turned on, the current of the DC power supply 10 passes through the first switch 11 and the load 12 , and reaches the drain D of the first semiconductor 25 and the third resistor 23 through the second terminal 40 . The first terminal, the second terminal of the third resistor 23 and the first terminal T1 of the photocoupler 24, at this time, the gate G of the first semiconductor 25 has no gate G voltage, so the drain D of the first semiconductor 25 Open circuit with the source S, at the same time because the anode terminal A of the photocoupler 24 has no voltage supply, so the first end T1 and the second end T2 of the photocoupler 24 are open circuited. Since the drain electrode D and the source electrode S of the first semiconductor 25 are open circuited, the first end T1 and the second end T2 of the photocoupler 24 are open. Therefore, the load 12 is not supplied by the DC power supply 10; when the second switch 13 is turned on, the current from the DC power supply 10 passes through the first terminal 30, and then goes to the first resistor 21 to supply power to the gate G of the first semiconductor 25 , so the drain electrode D of the first semiconductor 25 is connected to the source electrode S. At this time, the DC power supply 10 supplies power to the load 12, and at the same time supplies power to the anode terminal A of the photocoupler 24 through the second resistor 22. Therefore, the photocoupler 24 is The first terminal T1 and the second terminal T2 are turned on; when the second switch 13 is open, since the gate G of the first semiconductor 25 is not supplied with power, the drain D and the source S of the first semiconductor 25 are open. When the DC power supply 10 does not supply power to the load 12 and does not supply power to the anode terminal A of the photocoupler 24, the first terminal T1 and the second terminal T2 of the photocoupler 24 are open-circuited.

As shown in FIG. 4 , the short-circuit protection action principle of the load 12 of the DC short-circuit protection device of the present invention is as follows:

It can be seen from the above that when the first switch 11 and the second switch 13 are turned on, the load 12 is powered by the DC power supply 10; when both ends of the load 12 are short-circuited, according to the output characteristic curve table of the first semiconductor 25, when the first semiconductor 25 When the drain current of the first semiconductor 25 rises to its corresponding drain-source voltage and is higher than the turn-on voltage between the first terminal T1 and the second terminal T2 of the photocoupler 24, the drain-source voltage of the first semiconductor 25 supplies power to the first terminal T1 and the second terminal T2. The gate electrode G of the second semiconductor 26, the drain electrode D and the source electrode S of the second semiconductor 26 are conductive at this time, so the drain electrode D and the source electrode S of the first semiconductor 25 are open-circuited, the DC power supply 10 does not supply power to the short-circuit load 12, and so that the DC power supply 10 is protected;

Similarly, the on-voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24 is appropriately selected to match the voltage of the first semiconductor 25 . The required overload sink current can also achieve the function of overload protection.

It can be seen from the above that changing the second semiconductor 26 of FIG. 2 from an N-type semiconductor to an N-channel metal oxide semiconductor field effect transistor has the same operating principle and the same function of protecting the DC power supply 10 when the load 12 is short-circuited.

As shown in FIG. 5, it is the fourth embodiment of the DC short circuit protection device of the present invention. It can be seen from the figure that the first semiconductor 25 and the second semiconductor 26 in FIG. 3 are changed from N-type semiconductors to insulated gate bipolar electrodes. Crystal, the photocoupler 24 is of the transistor output type, and can also be of the Darlington composite transistor output type or photorelay, because its operation principle and function are the same as those of the transistor output type, and other circuit structures are the same as Figure 3. Repeat.

As shown in Figure 5, the operating principle of the DC short-circuit protection device of the present invention is as follows:

As shown in FIG. 5 , when the first switch 11 is turned on, the current of the DC power supply 10 passes through the first switch 11 and the load 12 , and reaches the drain D of the first semiconductor 25 and the third resistor 23 through the second terminal 40 . The first end, the second end of the third resistor 23 goes to the first end T1 of the photocoupler 24, at this time the gate G of the first semiconductor 25 has no gate G voltage, so the collector C of the first semiconductor 25 Open circuit with the emitter E, and because the anode terminal A of the photocoupler 24 has no voltage supply, the first terminal T1 and the second terminal T2 of the photocoupler 24 are open circuited, because the collector C and the emitter E of the first semiconductor 25 Open circuit, and open circuit between the first terminal T1 and the second terminal T2 of the photocoupler 24, so the load 12 is not supplied by the DC power supply 10; when the second switch 13 is turned on, the current from the DC power supply 10 passes through the first terminal 30 , and then the first resistor 21 supplies power to the gate G of the first semiconductor 25, so the collector C of the first semiconductor 25 is connected to the emitter E. At this time, the DC power supply 10 supplies power to the load 12, and passes through The second resistor 22 supplies power to the anode terminal A of the optocoupler 24, so the first terminal T1 and the second terminal T2 of the optocoupler 24 are conductive; when the second switch 13 is open, the first semiconductor is not supplied with power. The gate G of 25, so the collector C and the emitter E of the first semiconductor 25 are open-circuited. At this time, the DC power supply 10 does not supply power to the load 12, and does not supply power to the anode terminal A of the photocoupler 24. Therefore, the photocoupler 24 There is an open circuit between the first terminal T1 and the second terminal T2 of the .

As shown in FIG. 5 , the short-circuit protection action principle of the load 12 of the DC short-circuit protection device of the present invention is as follows:

It can be seen from the above that when the first switch 11 and the second switch 13 are turned on, the load 12 is powered by the DC power supply 10; when both ends of the load 12 are short-circuited, according to the output characteristic curve table of the first semiconductor 25, when the first semiconductor 25 When the collector current of the first semiconductor 25 rises to the point where the corresponding collector-emitter voltage reaches higher than the turn-on voltage between the first terminal T1 and the second terminal T2 of the photocoupler 24, the collector-emitter voltage of the first semiconductor 25 supplies power to the first terminal T1 and the second terminal T2. At the gate G of the second semiconductor 26, the collector C and the emitter E of the second semiconductor 26 are turned on, so the collector C and the emitter S of the first semiconductor 25 are open-circuited, the DC power supply 10 does not supply power to the short-circuit load 12, and so that the DC power supply 10 is protected;

Similarly, the on-voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24 can be appropriately selected, and the overload protection function can also be achieved in accordance with the overload collector current required by the first semiconductor 25 .

As can be seen from the above, the first semiconductor 25 and the second semiconductor 26 in FIG. 3 are changed from N-type semiconductors to insulated gate bipolar transistors, and the functions of protecting the DC power supply 10 when the load 12 is short-circuited are also the same.

As shown in FIG. 6 , it is the fifth embodiment of the DC short-circuit protection device of the present invention. As can be seen from the figure, the first terminal T1 and the second terminal T2 of the photocoupler 24 of FIG. 2 are connected to the first terminal T1 and the second terminal T2 of the first semiconductor 25 brake Between the pole G and the collector C of the second semiconductor 26, other circuit structures are the same as those in FIG. 2 and will not be repeated.

As shown in Figure 6, the operating principle of the DC short-circuit protection device of the present invention is as follows:

As shown in FIG. 6 , when the first switch 11 is turned on, the current of the DC power source 10 passes through the first switch 11 and the load 12 , and then passes through the second terminal 40 to the drain D of the first semiconductor 25 and the third resistor 23 At this time, the gate G of the first semiconductor 25 has no gate G voltage, so the drain D of the first semiconductor 25 is open to the source S, and at the same time, because the anode terminal A of the photocoupler 24 has no voltage, the photoelectric The first terminal T1 and the second terminal T2 of the coupler 24 are open. Since the drain D and the source S of the first semiconductor 25 are open, and the first terminal T1 and the second terminal T2 of the photocoupler 24 are open, so The load 12 is not supplied by the DC power supply 10, but the DC power supply 10 passes through the load 12 to the first end to the second end of the third resistor 23 and then to the base B of the second semiconductor 26, and the collector C of the second semiconductor 26 at this time Conducted with the emitter E, the function of the third resistor 23 is to limit the current of the DC power supply 10, which can protect the second semiconductor 26;

When the second switch 13 is turned on, the DC power supply 10 supplies power to the first resistor 21 to the gate G of the first semiconductor 25, so the drain D and the source S of the first semiconductor 25 are turned on, and the DC power supply 10 supplies power at this time In the load 12, then the DC power supply 10 supplies power to the second resistor 22 to the anode terminal A of the photocoupler 24, so the first terminal T1 and the second terminal T2 of the photocoupler 24 are conductive; when the second switch 13 When the circuit is open, since the DC power supply 10 does not supply power to the gate G of the first semiconductor 25, the drain D and the source S of the first semiconductor 25 are open-circuited. At this time, the DC power supply 10 does not supply power to the load 12, and the DC power supply 10 does not Power is supplied to the anode terminal A of the photocoupler 24, so the first terminal T1 and the second terminal of the photocoupler 24 Open circuit between T2.

It can be seen from the above operating principle that the first semiconductor 25 in FIG. 6 is changed from an N-channel metal-oxide-semiconductor field effect transistor to an N-type transistor, which is the same as the operating principle in FIG. 25 The N-channel metal oxide semiconductor field effect transistor can be changed to an N-type transistor.

It can be seen from the above-mentioned operation principle that changing the second semiconductor 26 of FIG. 6 from an N-type transistor to an N-channel metal oxide semiconductor field effect transistor is the same as the operation principle of FIG. 26 can be changed from N-type transistor to N-channel metal oxide semiconductor field effect transistor.

It can be seen from the above-mentioned operation principle that the first semiconductor 25 in FIG. 6 is changed from an N-channel metal oxide semiconductor field effect transistor to an insulated gate bipolar transistor, which is the same as the operation principle of FIG. The first semiconductor 25 can be changed from an N-channel metal oxide semiconductor field effect transistor to an insulated gate bipolar transistor.

As shown in FIG. 6 , the short-circuit protection action principle of the load 12 of the DC short-circuit protection device of the present invention is as follows:

It can be seen from the above that when the first switch 11 and the second switch 13 are turned on, the load 12 is powered by the DC power supply 10; when both ends of the load 12 are short-circuited, according to the output characteristic curve table of the first semiconductor 25, when the first semiconductor 25 The drain current of the first semiconductor 25 rises to its corresponding drain-source voltage and is higher than the base-emitter turn-on voltage of the second semiconductor 26. At this time, the drain-source voltage of the first semiconductor 25 supplies power to the base B of the second semiconductor 26, Therefore, the collector C and the emitter E of the second semiconductor 26 are conducting, because the first terminal T1 and the second terminal T2 of the photocoupler 24 are also conducting, so the drain D and the source S of the first semiconductor 25 are open. , the DC power supply 10 does not supply power to the short-circuit load 12, so that the DC power supply 10 is protected; When the resistance value of the third resistor 23 and the turn-on voltage between the first terminal T1 and the second terminal T2 of the optocoupler 24 are selected, the overload drain current required by the first semiconductor 25 can also be used to achieve overload protection. Features.

It can be seen from the above operating principle that the function of protecting the DC power supply 10 when the load 12 is short-circuited is also the same by changing the connection position of the photocoupler 24 in FIG. 2 .

It can be seen from the above operating principle that the first semiconductor 25 and the second semiconductor 26 shown in FIG. 2 , FIG. 3 , FIG. 4 and FIG. The first semiconductor 25 and the second semiconductor 26 can also be replaced and transformed, and the operation principle is the same and will not be described in detail.

From the description of the above-mentioned operation principle and functional operation, it can be seen that the present invention can be implemented accordingly.

10: DC power supply

11: The first switch

12: Load

13: Second switch

20: DC short-circuit protection device of the present invention

21: First resistor

22: Second resistor

23: Third resistor

24: Photocoupler

25: First Semiconductor

26: Second Semiconductor

27: Ground terminal

30: The first terminal

40: The second terminal

50: The third terminal

Claims (10)

A DC short-circuit protection device has the function of protecting the DC power supply from overload or short-circuit of the DC power supply during the power supply process. The DC short-circuit protection device includes: a first semiconductor having a drain or collector, a source or emitter and a gate or base; A second semiconductor has a drain or collector, a source or emitter and a gate or base, the drain or collector is connected to the gate or base of the first semiconductor, the source or emitter electrode is connected to the source or emitter of the first semiconductor; a first resistor with a first end and a second end, the second end is connected to the gate or base of the first semiconductor and the drain or collector of the second semiconductor, and has the function of limiting current; a second resistor, having a first end and a second end, the first end is connected to the first end of the first resistor, and has the function of limiting current; a third resistor, having a first end and a second end, the first end is connected to the drain or collector of the first semiconductor, and has the function of limiting current; and An optocoupler has an anode end, a cathode end, a first end and a second end, the first end is connected to the second end of the third resistor, and the second end is connected to the gate of the second semiconductor or base, the anode terminal is connected to the second terminal of the second resistor, the cathode terminal, the source or emitter of the first semiconductor and the source or emitter of the second semiconductor are connected together to become the ground terminal or The third terminal is used for connecting the negative terminal of the external voltage source. The DC short circuit protection device as claimed in claim 1, wherein the first end of the first resistor and the first end of the second resistor are connected together to form a first terminal for providing an external voltage source positive For electrical connection. The DC short circuit protection device as described in claim 1, wherein the first semiconductor drain or collector and the first end of the third resistor are connected together to form a second terminal for providing the external For load connection. The DC short circuit protection device of claim 1, wherein the first semiconductor or the second semiconductor is an N-channel metal oxide semiconductor field effect transistor, an N-type transistor or an insulated gate bipolar transistor. The DC short-circuit protection device according to claim 1, wherein the optocoupler is a transistor output type, a Darlington composite transistor output type or a photorelay. A DC short-circuit protection device has the function of protecting the DC power supply from overload or short-circuit of the DC power supply during the power supply process. The DC short-circuit protection device includes: a first semiconductor having a drain or collector, a source or emitter and a gate or base; a second semiconductor having a collector or drain, an emitter or source and a base or gate, the emitter or source is connected to the source or emitter of the first semiconductor; a first resistor, having a first end and a second end, the second end is connected to the gate or base of the first semiconductor, and has the function of limiting current; a second resistor, having a first end and a second end, the first end is connected to the first end of the first resistor, and has the function of limiting current; A third resistor has a first end and a second end, the first end is connected to the drain or collector of the first semiconductor, the second end is connected to the base or gate of the second semiconductor, and has The function of limiting current; and An optocoupler has an anode end, a cathode end, a first end and a second end, the first end is connected to the second end of the first resistor and the gate or base of the first semiconductor, the The second terminal is connected to the collector or drain of the second semiconductor, the anode terminal is connected to the second terminal of the second resistor, the cathode terminal, the source or emitter of the first semiconductor and the emitter of the second semiconductor The poles or sources are connected together to form a ground terminal or a third terminal, which is used for connecting the negative terminal of the external voltage source. The DC short circuit protection device as claimed in claim 6, wherein the first end of the first resistor and the first end of the second resistor are connected together to form a first terminal for providing an external voltage source The positive terminal of the connection is used. The DC short circuit protection device as claimed in claim 6, wherein the first semiconductor drain or collector and the first end of the third resistor are connected together to form a second terminal for providing the external For load connection. The DC short circuit protection device as claimed in claim 6, wherein the first semiconductor or the second semiconductor is an N-channel metal oxide semiconductor field effect transistor, an N-type transistor or an insulated gate bipolar transistor. The DC short-circuit protection device according to claim 6, wherein the optocoupler is a transistor output type, a Darlington composite transistor output type or a photorelay.

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