CN201854007U - High-precision overcurrent protection circuit - Google Patents
High-precision overcurrent protection circuit Download PDFInfo
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- CN201854007U CN201854007U CN2010206274924U CN201020627492U CN201854007U CN 201854007 U CN201854007 U CN 201854007U CN 2010206274924 U CN2010206274924 U CN 2010206274924U CN 201020627492 U CN201020627492 U CN 201020627492U CN 201854007 U CN201854007 U CN 201854007U
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- overcurrent protection
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- 238000005070 sampling Methods 0.000 claims abstract description 54
- 230000003287 optical effect Effects 0.000 claims description 11
- 239000003990 capacitor Substances 0.000 claims description 10
- 230000003321 amplification Effects 0.000 claims description 3
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 3
- 208000031361 Hiccup Diseases 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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Abstract
The utility model discloses a high-precision overcurrent protection circuit which comprises a circuit sampling circuit, an amplifying unit, a voltage comparing unit and a control unit. The working principle of the protection circuit comprises the steps of: sampling a current which flows through a load to obtain a sampling voltage value, and amplifying the sampling voltage value; and comparing the amplified sampling voltage value with a set reference voltage value, generating a corresponding indicating signal according to a compared result, and controlling a switch power supply to be switched on or off. The high-precision overcurrent protection circuit has the characteristics that the overcurrent protection precision is high, a overcurrent protection point is easily debugged, and the temperature drift of the overcurrent protection point is small, so that the problems of the bad reliability, the bad overcurrent protection precision and the like in a conventional overcurrent protection circuit are solved. Furthermore, the high-precision overcurrent protection circuit is high in stability, small in temperature shift, simple in circuit structure, and low in cost, and can be used for the field with higher requirement on control precision for the overcurrent protection.
Description
Technical Field
The utility model belongs to the technical field of power protection, a overcurrent protection circuit of protection load is related to, concretely relates to high accuracy overcurrent protection circuit.
Background
The purpose of overcurrent protection is to limit the output current of the switching power supply within a fixed range, and protect the whole system or load when the output of the switching power supply is overloaded or short-circuited. The current common overcurrent protection circuits have the problems of poor overcurrent protection precision, difficult debugging of overcurrent protection points, large temperature drift of the overcurrent protection points and the like, and limit the application range of the overcurrent protection circuits.
SUMMERY OF THE UTILITY MODEL
In order to overcome the problem that exists among the above-mentioned prior art, the utility model aims at providing a high accuracy overcurrent protection circuit that overcurrent protection precision is high, the debugging of overcurrent protection point is easy, the overcurrent protection point temperature floats for a short time, has solved the problem that exists among the prior art.
In order to achieve the above object, the utility model adopts the following technical scheme:
a high-precision overcurrent protection circuit comprises a current sampling circuit, an amplifying unit, a voltage comparing unit and a control unit; wherein,
the current sampling circuit is used for sampling current flowing through a load to obtain a sampling voltage value of the sampling current and transmitting the sampling voltage value to the amplifying unit;
the amplifying unit is used for receiving the sampling voltage value transmitted by the current sampling circuit, amplifying the received sampling voltage value and transmitting the amplified sampling voltage value to the voltage comparing unit;
the voltage comparison unit is used for receiving the amplified sampling voltage value transmitted by the amplification unit, comparing the received amplified sampling voltage value with a set reference voltage value, generating a corresponding indication signal according to a comparison result, and transmitting the indication signal to the control unit;
and the control unit is used for receiving the indication signal transmitted by the voltage comparison unit and controlling the switching-on or switching-off of the switching power supply according to the received indication signal.
The utility model discloses high accuracy overcurrent protection circuit has that the overcurrent protection precision is high, the debugging of overcurrent protection point is easy, the temperature of overcurrent protection point floats little characteristics, has solved reliability, the poor scheduling problem of overcurrent protection precision that exists among the traditional overcurrent protection circuit. And the circuit has high stability, small temperature drift, simple circuit structure and low cost, and can be used in the field with higher requirement on the precision of control over overcurrent protection.
Drawings
Fig. 1 is a schematic structural diagram of the overcurrent protection circuit of the present invention.
Fig. 2 is a schematic diagram of the overcurrent protection circuit of the present invention.
In fig. 1, 1 is a current sampling circuit, 2 is an amplifying unit, 3 is a voltage comparing unit, and 4 is a control unit.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the present invention discloses a structure of an overcurrent protection circuit. The device comprises a current sampling circuit 1, an amplifying unit 2, a voltage comparing unit 3 and a control unit 4 which are connected in sequence;
the current sampling circuit 1 is used for sampling current flowing through a load, obtaining a sampling voltage value of the sampling current and then transmitting the sampling voltage value to the amplifying unit 2;
the amplifying unit 2 is used for receiving the sampling voltage value transmitted by the current sampling circuit 1, amplifying the received sampling voltage value, and then transmitting the amplified sampling voltage value to the voltage comparing unit 3;
the voltage comparison unit 3 is used for receiving the amplified sampling voltage value transmitted by the amplification unit 2, comparing the received amplified sampling voltage value with a set reference voltage value, generating a corresponding indication signal according to a comparison result, and transmitting the indication signal to the control unit 4;
and the control unit 4 is used for receiving the indication signal transmitted by the voltage comparison unit 3 and controlling the switching power supply to be switched on or switched off according to the received indication signal.
The utility model discloses overcurrent protection circuit's schematic diagram, as shown in FIG. 2. The current sampling circuit 1 includes a current sampling resistor RS. Two ends of the current sampling resistor RS are respectively connected with the first output negative voltage Com and the second output negative voltage Com1 of the secondary side of the switching power supply. The amplifying unit 2 includes an operational amplifier IC1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3, and a fourth capacitor C4. The voltage comparison unit 3 comprises a third resistor R3, a light emitting diode IC2B of an optical coupler IC2 and a precision voltage reference IC 3. The control unit 4 includes a phototransistor IC2A of an optocoupler IC2, a first resistor R1 and a second resistor R2.
The positive input pin 7 of the operational amplifier IC1 is connected to one end of the third resistor R3, the output positive voltage Vout of the secondary side of the switching power supply, and the non-inverting input pin 3 of the operational amplifier IC1 is connected to the first output negative voltage Com; an inverting input pin 2 of the operational amplifier IC1 is connected to one end of the third capacitor C3, one end of the fourth resistor R4, one end of the fifth resistor R5, and one end of the sixth resistor R6, respectively; the output pin 6 of the operational amplifier IC1 is connected to the pin R of the precision voltage reference IC3, the other end of the third capacitor C3, the other end of the fourth resistor R4, and one end of the fourth capacitor C4, respectively. The pin a of the precision voltage reference IC3, the other end of the fourth capacitor C4, the negative input pin 4 of the operational amplifier IC1, the other end of the fifth resistor R5, and the other end of the sixth resistor R6 are connected to the second output negative voltage Com 1. The other end of the third resistor R3 is connected with the anode of the LED IC2B of the optical coupler IC2, and the cathode of the LED IC2B of the optical coupler IC2 is connected with the pin K of the precision voltage reference IC 3.
The collector of a photosensitive triode IC2A of the optical coupler IC2 is connected with a primary positive power supply Vcc of a switching power supply, the emitter of a photosensitive triode IC2A of the optical coupler IC2 is connected with one end of a first resistor R1, the other end of the first resistor R1 is respectively connected with a control signal and one end of a second resistor R2, and the other end of the second resistor R2 is connected with a primary input negative power supply Vin-of the switching power supply.
The overcurrent protection circuit is connected with a primary side of a switching power supply and a secondary side of the switching power supply. The method comprises the steps of firstly sampling current flowing through a load to obtain a sampling voltage value of the current, then amplifying the sampling voltage value, and comparing the sampling voltage value with a set 2.5V reference voltage value. When the sampling voltage value reaches a set 2.5V reference voltage value (namely the output current of the switching power supply exceeds the normal working current and reaches a set overcurrent protection range), the amplified sampling voltage value is greater than the 2.5V reference voltage value, the optical coupler IC2 is conducted, an overcurrent indication signal is output, and the indication signal is transmitted to the primary side of the switching power supply; the control unit 4 sends the turn-off signal to the control pin of the PWM, and the turn-off signal is used for stopping the conduction of the switch of the switching power supply, so that the circuit is protected. If the overcurrent is not eliminated, the PWM enters the cycle states of starting, closing, restarting and closing again, namely hiccup phenomenon.
The overcurrent protection circuit has the advantages of high stability, small temperature drift, simple circuit structure and low cost, and can be used in the field with higher requirements on control overcurrent protection precision.
Claims (3)
1. The high-precision overcurrent protection circuit is characterized by comprising a current sampling circuit (1), an amplifying unit (2), a voltage comparison unit (3) and a control unit (4); wherein,
the current sampling circuit (1) is used for sampling current flowing through a load to obtain a sampling voltage value of the sampling current and transmitting the sampling voltage value to the amplifying unit (2);
the amplifying unit (2) is used for receiving the sampling voltage value transmitted by the current sampling circuit (1), amplifying the received sampling voltage value and transmitting the amplified sampling voltage value to the voltage comparing unit (3);
the voltage comparison unit (3) is used for receiving the amplified sampling voltage value transmitted by the amplification unit (2), comparing the received amplified sampling voltage value with a set reference voltage value, generating a corresponding indication signal according to a comparison result, and sending the indication signal to the control unit (4);
and the control unit (4) is used for receiving the indication signal transmitted by the voltage comparison unit (3) and controlling the on or off of the switching power supply according to the received indication signal.
2. A high precision current protection circuit according to claim 1, characterized in that the current sampling circuit (1) comprises a current sampling Resistor (RS), and the two ends of the current sampling Resistor (RS) are respectively connected with a first output negative voltage (Com) and a second output negative voltage (Com 1); the amplifying unit (2) comprises an operational amplifier (IC 1), a positive input pin 7 of the operational amplifier (IC 1) is connected with an output positive voltage (Vout), a non-inverting input pin 3 of the operational amplifier (IC 1) is connected with a first output negative voltage (Com), an inverting input pin 2 of the operational amplifier (IC 1) is respectively connected with one end of a third capacitor (C3), one end of a fourth resistor (R4), one end of a fifth resistor (R5) and one end of a sixth resistor (R6), an output pin 6 of the operational amplifier (IC 1) is respectively connected with the other end of the third capacitor (C3), the other end of the fourth resistor (R4) and one end of a fourth capacitor (C4), the other end of the fourth capacitor (C4), the negative input pin 4 of the operational amplifier (IC 1), the other end of the fifth resistor (R5) and the other negative voltage (Com 1) of the sixth resistor (R6) are respectively connected with a second output negative voltage (Com 1); the voltage comparison unit (3) comprises a third resistor (R3), one end of the third resistor (R3) is connected with an output positive voltage (Vout), the other end of the third resistor (R3) is connected with the anode of a light-emitting diode (IC 2B) of the optical coupler (IC 2), the cathode of the light-emitting diode (IC 2B) of the optical coupler (IC 2) is connected with a pin K of a voltage reference (IC 3), a pin A of the voltage reference (IC 3) is connected with a second output negative voltage (Com 1), and a pin R of the voltage reference (IC 3) is connected with an output pin 6 of an operational amplifier (IC 1); the control unit (4) comprises a photosensitive triode (IC 2A) of an optical coupler (IC 2), a collector of the photosensitive triode (IC 2A) of the optical coupler (IC 2) is connected with a primary positive power supply Vcc of a switching power supply, an emitter of the photosensitive triode (IC 2A) of the optical coupler (IC 2) is connected with one end of a first resistor (R1), the other end of the first resistor (R1) is connected with one end of a second resistor (R2), and the other end of the second resistor (R2) is connected with an input negative power supply Vin-.
3. A high precision current protection circuit according to claim 2, characterized in that said voltage reference (IC 3) is a precision voltage reference.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206274924U CN201854007U (en) | 2010-11-26 | 2010-11-26 | High-precision overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206274924U CN201854007U (en) | 2010-11-26 | 2010-11-26 | High-precision overcurrent protection circuit |
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| Publication Number | Publication Date |
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| CN201854007U true CN201854007U (en) | 2011-06-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2010206274924U Expired - Fee Related CN201854007U (en) | 2010-11-26 | 2010-11-26 | High-precision overcurrent protection circuit |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102377172A (en) * | 2011-10-28 | 2012-03-14 | 深圳市星龙科技有限公司 | Three-phase program controlled power source and power amplifier tube short-circuiting protective circuit thereof |
| CN103022963A (en) * | 2012-12-04 | 2013-04-03 | 北京经纬恒润科技有限公司 | High-end over-current protection circuit |
| CN104717772A (en) * | 2015-03-16 | 2015-06-17 | 昂宝电子（上海）有限公司 | Control circuit and method for induction cooker overcurrent protection |
| CN105203888A (en) * | 2015-10-21 | 2015-12-30 | 上海斐讯数据通信技术有限公司 | Overcurrent protection method and device for LCD (liquid crystal display) screen in test |
| CN105741777A (en) * | 2014-12-24 | 2016-07-06 | 乐金显示有限公司 | Over-current control device and organic light emitting display device adpoting the same |
| CN106843354A (en) * | 2017-04-11 | 2017-06-13 | 惠科股份有限公司 | Overcurrent protection circuit, display panel and display device |
| US10379553B2 (en) | 2017-04-11 | 2019-08-13 | HKC Corporation Limited | Overcurrent protection circuit, display panel, and display device |
| CN110971216A (en) * | 2018-12-06 | 2020-04-07 | 宁德时代新能源科技股份有限公司 | Overcurrent protection circuit |
-
2010
- 2010-11-26 CN CN2010206274924U patent/CN201854007U/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102377172A (en) * | 2011-10-28 | 2012-03-14 | 深圳市星龙科技有限公司 | Three-phase program controlled power source and power amplifier tube short-circuiting protective circuit thereof |
| CN102377172B (en) * | 2011-10-28 | 2013-11-20 | 深圳市星龙科技有限公司 | Three-phase program controlled power source and power amplifier tube short-circuiting protective circuit thereof |
| CN103022963A (en) * | 2012-12-04 | 2013-04-03 | 北京经纬恒润科技有限公司 | High-end over-current protection circuit |
| CN103022963B (en) * | 2012-12-04 | 2015-01-21 | 北京经纬恒润科技有限公司 | High-end over-current protection circuit |
| CN105741777A (en) * | 2014-12-24 | 2016-07-06 | 乐金显示有限公司 | Over-current control device and organic light emitting display device adpoting the same |
| CN105741777B (en) * | 2014-12-24 | 2019-04-09 | 乐金显示有限公司 | Excess current control device and the organic light-emitting display device for using it |
| CN104717772A (en) * | 2015-03-16 | 2015-06-17 | 昂宝电子（上海）有限公司 | Control circuit and method for induction cooker overcurrent protection |
| CN104717772B (en) * | 2015-03-16 | 2017-10-17 | 昂宝电子（上海）有限公司 | Control circuit and control method for electromagnetic oven overcurrent protection |
| CN105203888A (en) * | 2015-10-21 | 2015-12-30 | 上海斐讯数据通信技术有限公司 | Overcurrent protection method and device for LCD (liquid crystal display) screen in test |
| CN106843354A (en) * | 2017-04-11 | 2017-06-13 | 惠科股份有限公司 | Overcurrent protection circuit, display panel and display device |
| US10379553B2 (en) | 2017-04-11 | 2019-08-13 | HKC Corporation Limited | Overcurrent protection circuit, display panel, and display device |
| CN110971216A (en) * | 2018-12-06 | 2020-04-07 | 宁德时代新能源科技股份有限公司 | Overcurrent protection circuit |
| CN110971216B (en) * | 2018-12-06 | 2021-08-17 | 宁德时代新能源科技股份有限公司 | Overcurrent protection circuit |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110601 Termination date: 20171126 |
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| CF01 | Termination of patent right due to non-payment of annual fee |