CN107968379B - Solid-state direct current protection circuit - Google Patents
Solid-state direct current protection circuit Download PDFInfo
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- CN107968379B CN107968379B CN201810044772.3A CN201810044772A CN107968379B CN 107968379 B CN107968379 B CN 107968379B CN 201810044772 A CN201810044772 A CN 201810044772A CN 107968379 B CN107968379 B CN 107968379B
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- npn triode
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- switching tube
- resistor
- direct current
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- 238000011084 recovery Methods 0.000 claims abstract description 13
- 238000005070 sampling Methods 0.000 claims abstract description 10
- 239000007787 solid Substances 0.000 claims 3
- 230000009471 action Effects 0.000 abstract description 4
- 230000008859 change Effects 0.000 abstract description 3
- 230000000087 stabilizing effect Effects 0.000 abstract description 2
- 230000001681 protective effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
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- Electronic Switches (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention relates to a solid-state direct current protection circuit, wherein a direct current power supply is connected with the cathode of a freewheeling diode and one end of a load, the other end of the load is connected with the base electrode of a second NPN triode through a series current limiting resistor and a recovery switch, the collector electrode of the second NPN triode is connected with the direct current power supply through a pull-up resistor, the emitter electrode of the second NPN triode is connected with the grid electrode of a transistor type switching tube through a sampling resistor and is connected with the anode of the freewheeling diode and the other end of the load through the drain electrode of the switching tube, the drain electrode of the switching tube is also connected with the base electrode of a first NPN triode, the emitter electrode of the first NPN triode is connected with the cathode of the direct current power supply, the collector electrode of the switching tube is connected with the source electrode of the switching tube, and a parallel voltage stabilizing diode and a pull-down resistor are arranged between the base electrode of the first NPN triode and the source electrode of the switching tube. The invention has simple structure, wide applicable voltage range and short action time, can flexibly change parameters and redesign according to actual occasions, and has a self-locking function.
Description
Technical Field
The invention relates to a circuit structure, in particular to a solid-state direct-current protection circuit.
Background
At present, a plurality of power supply products have overcurrent protection functions, which embody the important position of overcurrent protection in power supply safety, and the existing overcurrent protection means mainly comprise the following steps: 1. an air switch is used. 2. And (5) carrying out power supply design by using a switching power supply chip with overcurrent protection. 3. And a fuse is connected in series. 4 series connection self-recovery protective tube.
The above scheme has the defects that: 1. an air switch: because of the mechanical structure, arcing may occur during tripping, and frequent protective actions will greatly reduce the life of the blank. 2. The power supply design is carried out by using a switching power supply chip with overcurrent protection: the structure is complex, and a large amount of calculation is needed for each design. 3. A series fuse: the fuse is a disposable element, and can be scrapped in each protection action, which is uneconomical. 4 self-restoring protective tube: is a good alternative to the traditional fuse, but has low withstand voltage and is limited in high voltage and high power occasions.
In general, the above solutions have the problem of low flexibility, and the design is redesigned and even the components of different types are replaced every time the parameters are changed, which brings great inconvenience to the user.
Disclosure of Invention
The invention provides a solid-state direct current protection circuit which has simple structure, wide applicable voltage range, flexible parameter change and self-locking function.
The solid-state direct current protection circuit comprises a direct current power supply, a positive electrode of a follow current diode and one end of a load, wherein the other end of the load is connected with a base electrode of a second NPN triode through a current limiting resistor and a recovery switch which are connected in series, a collector electrode of the second NPN triode is connected with the positive electrode of the direct current power supply through a pull-up resistor, an emitter electrode of the second NPN triode is connected with a grid electrode of a transistor type switching tube through a sampling resistor and is connected with the positive electrode of the follow current diode and the other end of the load through a drain electrode of the switching tube, a drain electrode of the switching tube is also connected with a base electrode of a first NPN triode, an emitter electrode of the first NPN triode is connected with the negative electrode of the direct current power supply, a collector electrode of the switching tube is connected with a source electrode of the switching tube, and a parallel voltage stabilizing diode and a pull-down resistor are arranged between the base electrode of the first NPN triode and the source electrode of the switching tube.
The invention has the advantages that the integrated circuit can be conveniently manufactured because no energy storage element (inductance and capacitance) is used, and the advantages include: 1. simple structure and high reliability. 2. When redesigning, the calculation parameters are easy, the power consumption of the circuit is mainly considered, and only the resistance value of the sampling resistor is required to be changed when the rated value of the protection current is changed. 3. Each design can be applied to a wide voltage range. 4. Because the power element uses the transistor, the response speed is high, the ignition condition of the mechanical structure can not occur, and the service life is long. 5. No separate power supply for the control circuit is required.
Furthermore, a protection indicator lamp and an LED current limiting resistor are connected in series between the base electrode of the first NPN triode and the drain electrode of the switch tube, and the overvoltage protection can be prompted by the illumination of the protection indicator lamp.
Preferably, the switching transistor is a MOSFET transistor (metal oxide semiconductor field effect transistor) or an IGBT transistor (insulated gate bipolar transistor).
Further, the switching transistor is an N-channel insulated gate type MOSFET transistor or an IGBT transistor.
Further, the load is an adjustable resistor, and can be any type of load.
The solid-state direct current protection circuit has the advantages of simple structure, wide applicable voltage range, short action time, flexible parameter change, redesign according to actual occasions and self-locking function.
The foregoing of the invention will be described in further detail with reference to the following detailed description of the examples. It should not be understood that the scope of the above subject matter of the present invention is limited to the following examples only. Various substitutions and alterations are also possible, without departing from the spirit of the invention, and are intended to be within the scope of the invention.
Drawings
Fig. 1 is a schematic circuit diagram of a solid-state dc-dc protection circuit according to the present invention.
Detailed Description
As shown in fig. 1, the positive electrode of the direct current power supply U1 is connected to the negative electrode of the freewheeling diode D1 and one end of the load R6. The load R6 may be an adjustable resistor, the other end of the load R6 is connected with the base electrode of the second NPN triode Q2 through a current limiting resistor R5 and a recovery switch S1 which are connected in series, and the collector electrode of the second NPN triode Q2 is connected with the positive electrode of the direct current power supply U1 through a pull-up resistor R4. The recovery switch S1 is a normally closed non-self-locking switch and is used for recovering the conduction of the protection circuit when being pressed down. The emitter of the second NPN triode Q2 is connected to the gate of a switching tube Q3 of the MOSFET transistor or IGBT transistor type via a sampling resistor R1, and is connected to the anode of the freewheel diode D1 and the other end of the load R6 by the drain of the switching tube Q3. The pull-up resistor R4 serves as a pull-up resistor of the switching transistor Q3, and provides the gate driving voltage to the switching transistor Q3. The drain electrode of the switch tube Q3 is connected with the base electrode of the first NPN triode Q1 through a protection indicator light LED1 and an LED current limiting resistor R2 which are connected in series. The magnitude of the sampling resistor R1 is dependent on the protection current, and an adjustable resistor may be used. An emitter of the first NPN triode Q1 is connected with a negative electrode of the direct current power supply U1, a collector of the first NPN triode Q1 is connected with a source electrode of the switching tube Q3, and a parallel zener diode D2 and a pull-down resistor R3 are arranged between a base of the first NPN triode Q1 and the source electrode of the switching tube Q3. The pull-down resistor R3 serves as a pull-down resistor of Q3, so that the gate voltage of the switching transistor Q3 is 0 when the circuit is just powered on, and the switching transistor Q3 is in a closed (high-resistance) state. The first NPN triode Q1 and the second NPN triode Q2 can be selected from the group consisting of S8050, SS8050, 2N222, and the like. The freewheel diode D1 is used for preventing the switching tube Q3 from being broken down, and a fast recovery diode or a schottky diode with a withstand voltage greater than a rated voltage can be selected.
When the circuit is initially turned on to power supply U1, because of the effect of pull-down resistor R3, the gate voltage of switching tube Q3 is 0, at this time, switching tube Q3 is in a closed (high resistance) state, most of the power supply voltage is applied to two ends of switching tube Q3, at this time, the voltage difference between the two ends of current limiting resistor R5 and the voltage difference between the two ends of switching tube Q3 is not great, so that the base of second NPN triode Q2 has current passing through, because of the amplifying effect of the triode, the current passing through pull-up resistor R4 is released through second NPN triode Q2, the gate of switching tube Q3 keeps a low potential, switching tube Q3 is not turned on, and indicator light LED1 is protected.
When the circuit is in a conducting state and the protection state is not needed, the base electrode of the second NPN triode Q2 is not electrified when the recovery switch S1 is pressed, and the second NPN triode Q2 is turned off, because the action time of pressing the recovery switch S1 is in the millisecond level, the power supply U1 can charge the parasitic capacitance of the grid electrode of the switching tube Q3 through the pull-up resistor R4, and the switching tube Q3 is conducted. After the switch tube Q3 is turned on, the voltage at two ends of the switch tube Q3 is basically reduced to 0, at this time, the protection indicator LED1 is turned off, and after the recovery switch S1 is pressed, the voltage at two ends of the current limiting resistor R5 is also absent, so that the second NPN triode Q2 will maintain the off state, and the circuit is locked to be in the on state.
When the current is larger than the rated current of protection, the voltage at two ends of the sampling resistor R1 is larger than the conducting voltage of the first NPN triode Q1, the first NPN triode Q1 is rapidly conducted, the voltage of the grid electrode of the switching tube Q3 is pulled down, the switching tube Q3 is closed, the voltage at two ends of the switching tube Q3 is similar to the power supply voltage, the current limiting resistor R5 passes through the current again, the second NPN triode Q2 is conducted, the low potential of the grid electrode of the switching tube Q3 is kept, the protection indicator LED1 emits light, the voltage drop at two ends of the sampling resistor R1 is 0, the first NPN triode Q1 is closed, but the circuit is still in a closed state, and the circuit is locked to be in the closed state.
When the fault is relieved or the power of the load is smaller than the rated value, the recovery switch S1 is pressed, the conduction state of the second NPN triode Q2 is relieved, the switching tube Q3 is conducted again, and the normal conduction state of the circuit is recovered.
Claims (4)
1. The solid-state direct current protection circuit is characterized in that: the positive pole of the direct current power supply (U1) is connected with the negative pole of a follow current diode (D1) and one end of a load (R6), the other end of the load (R6) is connected with the base electrode of a second NPN triode (Q2) through a current limiting resistor (R5) and a recovery switch (S1) which are connected in series, the collector electrode of the second NPN triode (Q2) is connected with the positive pole of the direct current power supply (U1) through a pull-up resistor (R4), the emitter electrode of the second NPN triode (Q2) is connected with the grid electrode of a transistor type switching tube (Q3) through a sampling resistor (R1), the drain electrode of the switching tube (Q3) is connected to the positive pole of the follow current diode (D1) and the other end of the load (R6), the drain electrode of the switching tube (Q3) is also connected with the base electrode of the first NPN triode (Q1), the emitter electrode of the first NPN triode (Q1) is connected with the negative pole of the direct current power supply (U1), the collector electrode of the switching tube (Q3) is connected with the source electrode of the switching tube (Q3), the emitter electrode of the second NPN triode (Q2) is connected with the source electrode of the switching tube (Q1) through a pull-up resistor (Q1), the drain electrode of the switching tube (Q3) is connected between the first NPN triode (Q1) and the base electrode (Q3) and the base electrode of the LED (Q3) is connected with the current limiting resistor (Q3), the current-limiting resistor (Q3) is connected between the LED (Q1) and the base electrode (Q3) and the LED (Q3) and the current-down resistor (Q3) is connected in parallel, the switch tube (Q3) cannot be conducted, meanwhile, the protection indicator lamp (LED 1) emits light, when the circuit is conducted and the protection state is not needed, when the recovery switch (S1) is pressed down, the base electrode of the second NPN triode (Q2) does not have current any more, the second NPN triode (Q2) is turned off, the voltage at two ends of the switch tube (Q3) is basically reduced to 0, at the moment, the protection indicator lamp (LED 1) is turned off, when the current is larger than the rated current for protection, the voltage at two ends of the sampling resistor (R1) is larger than the conducting voltage of the first NPN triode (Q1), the first NPN triode (Q1) is conducted, the switch tube (Q3) is turned off, the second NPN triode (Q2) is conducted, the low potential of the grid electrode of the switch tube (Q3) is kept, the voltage at two ends of the sampling resistor (R1) is reduced to 0, the first NPN triode (Q1) is turned off, the circuit is locked to be in the off state, when the fault is relieved or the power of the load is smaller than the rated current, the recovery switch (Q1) is pressed down, the normal state of the second NPN triode (Q2) is turned on, and the normal state of the switch (Q) is turned on.
2. The solid state dc protection circuit of claim 1, wherein: the switching transistor (Q3) is a MOSFET transistor or an IGBT transistor.
3. The solid state dc protection circuit of claim 2, wherein: the switching transistor (Q3) is an N-channel insulated gate type MOSFET transistor or an IGBT transistor.
4. The solid state dc protection circuit of claim 1, wherein: the load (R6) is an adjustable resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810044772.3A CN107968379B (en) | 2018-01-17 | 2018-01-17 | Solid-state direct current protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810044772.3A CN107968379B (en) | 2018-01-17 | 2018-01-17 | Solid-state direct current protection circuit |
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| Publication Number | Publication Date |
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| CN107968379A CN107968379A (en) | 2018-04-27 |
| CN107968379B true CN107968379B (en) | 2024-05-17 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201810044772.3A Active CN107968379B (en) | 2018-01-17 | 2018-01-17 | Solid-state direct current protection circuit |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109149523B (en) * | 2018-08-10 | 2024-02-20 | 合肥华耀电子工业有限公司 | Self-recovery type overcurrent protection circuit |
| CN112531650A (en) * | 2020-12-07 | 2021-03-19 | 华羿微电子股份有限公司 | From power MOSFET who takes short-circuit protection |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3988643A (en) * | 1974-10-25 | 1976-10-26 | Litton Business Systems, Inc. | Latch circuit |
| SU1495892A1 (en) * | 1987-04-20 | 1989-07-23 | Предприятие П/Я В-8543 | Device for load short-ciruit protection of power supply unit |
| CN201750125U (en) * | 2010-06-24 | 2011-02-16 | 上海航天汽车机电股份有限公司 | Short circuit self-locking protection circuit |
| CN203367968U (en) * | 2013-07-12 | 2013-12-25 | 珠海格力电器股份有限公司 | Overcurrent protection circuit device of electric appliance and ultrasonic humidifier |
| WO2014039191A1 (en) * | 2012-09-06 | 2014-03-13 | Murata Manufacturing Co., Ltd. | Method and apparatus for continuous short-circuit protection |
| CN104795807A (en) * | 2015-04-16 | 2015-07-22 | 上海空间电源研究所 | High-reliability current protecting circuit for astronavigation |
| CN205178467U (en) * | 2015-10-29 | 2016-04-20 | 浙江大华技术股份有限公司 | Load short circuit protection circuit and dc supply equipment |
| CN207691408U (en) * | 2018-01-17 | 2018-08-03 | 攀枝花学院 | Solid-state direct-current current foldback circuit |
-
2018
- 2018-01-17 CN CN201810044772.3A patent/CN107968379B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3988643A (en) * | 1974-10-25 | 1976-10-26 | Litton Business Systems, Inc. | Latch circuit |
| SU1495892A1 (en) * | 1987-04-20 | 1989-07-23 | Предприятие П/Я В-8543 | Device for load short-ciruit protection of power supply unit |
| CN201750125U (en) * | 2010-06-24 | 2011-02-16 | 上海航天汽车机电股份有限公司 | Short circuit self-locking protection circuit |
| WO2014039191A1 (en) * | 2012-09-06 | 2014-03-13 | Murata Manufacturing Co., Ltd. | Method and apparatus for continuous short-circuit protection |
| CN203367968U (en) * | 2013-07-12 | 2013-12-25 | 珠海格力电器股份有限公司 | Overcurrent protection circuit device of electric appliance and ultrasonic humidifier |
| CN104795807A (en) * | 2015-04-16 | 2015-07-22 | 上海空间电源研究所 | High-reliability current protecting circuit for astronavigation |
| CN205178467U (en) * | 2015-10-29 | 2016-04-20 | 浙江大华技术股份有限公司 | Load short circuit protection circuit and dc supply equipment |
| CN207691408U (en) * | 2018-01-17 | 2018-08-03 | 攀枝花学院 | Solid-state direct-current current foldback circuit |
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| Publication number | Publication date |
|---|---|
| CN107968379A (en) | 2018-04-27 |
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