CN202917946U - Under-voltage protection circuit with return difference - Google Patents
Under-voltage protection circuit with return difference Download PDFInfo
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- CN202917946U CN202917946U CN 201220540141 CN201220540141U CN202917946U CN 202917946 U CN202917946 U CN 202917946U CN 201220540141 CN201220540141 CN 201220540141 CN 201220540141 U CN201220540141 U CN 201220540141U CN 202917946 U CN202917946 U CN 202917946U
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Abstract
The utility model discloses an under-voltage protection circuit with returndifference. The under-voltage protection circuit with return difference comprises a first voltage division resistor; one end of the first voltage division resistor serves as the input end of the control voltage; the other end of the first voltage division resistor is divided into two paths, one path is connected with the control electrode of a reference source, and the other path is grounded via a second voltage division resistor; the anode of the reference source is grounded, and the cathode of the reference source is connected with the negative input end of an optocoupler; the positive input end of the optocoupler is connected with a second power supply; the positive and negative output ends of the optocoupler are respectively connected with the corresponding control end of a controlled circuit; and a return difference circuit is connected between the cathode of the reference source and the control electrode. With the under-voltage protection circuit with return difference, the control of the control voltage on the controlled circuit is not influenced by the small fluctuation of the control voltage, the phenomenon of malfunction does not happen to the controlled circuit, under-voltage protection on the control voltage can be realized, the protection precision is high, and the return difference voltage can be accurately adjusted and easily controlled.
Description
Technical field
The utility model relates to a kind of under-voltage protecting circuit, espespecially a kind of under-voltage protecting circuit with return difference.
Background technology
Existing input and output over under-voltage protection circuit (namely inputing or outputing overvoltage or under-voltage protecting circuit) the relatively more commonly used operational amplifiers that adopt cooperate a reference source to realize more at present; its advantage is that the protection precision is high; return difference is controlled easily; but it is complicated that shortcoming is circuit; cost is high, must come to operational amplifier and a reference source power supply with special accessory power supply.
Fairly simple protective circuit such as using voltage-stabiliser tube or triode etc. to realize then precision is high and return difference is non-adjustable, can only be applied in some and require in the relatively loose environment.
The utility model content
The purpose of this utility model is to provide a kind of under-voltage protecting circuit with return difference; control is after voltage carries out under-voltage protection via the utility model, on the control of controlled circuit can controlled voltage self fuctuation within a narrow range impact, the protection precision is high; and hysteresis voltage can accurately be regulated, and is easy to control.
To achieve these goals, the utility model has adopted following technical scheme:
A kind of under-voltage protecting circuit with return difference; it is characterized in that: it comprises the first divider resistance; one end of this first divider resistance is as the input of control voltage; the other end of this first divider resistance divides two-way; one the tunnel is connected with the control utmost point of a reference source; another road is via the second divider resistance ground connection; the anode of this a reference source; negative electrode respectively with ground; the negative input end of optocoupler connects; the positive input terminal of this optocoupler is connected with second source; this optocoupler just; negative output terminal is connected with the corresponding controling end of controlled circuit respectively, is connected with the return difference circuit between the negative electrode of this a reference source and the control utmost point.
Described return difference circuit comprises the positive-negative-positive triode, the base stage of this positive-negative-positive triode is connected with the negative electrode of described a reference source via the second resistance, the first diode, the emitter of this positive-negative-positive triode connects the first power supply, be connected with the first resistance between the emitter of this positive-negative-positive triode and the base stage, the collector electrode of this positive-negative-positive triode is connected with the control utmost point of described a reference source via the 3rd resistance, the second diode.
The two ends of described the second divider resistance are parallel with filtering delay-time electric capacity.
Be connected with negative feedback electric capacity between the control utmost point of described a reference source and the negative electrode.
Be connected with leakage current protection resistance between the positive input terminal of described optocoupler and the negative input end.
Described the first diode is made of a diode, and perhaps described the first diode is made of a plurality of diodes in parallels; Described the second diode is made of a diode, and perhaps described the second diode is made of a plurality of diodes in parallels.
Described a reference source is the TL431 chip.
The utility model has the advantages that:
Compare with existing input and output over under-voltage protection circuit; the utility model has dispensed operational amplifier and has been the special-purpose accessory power supply of operational amplifier power supply; and can also bring into play the function of operational amplifier; a reference source also need not special-purpose accessory power supply power supply; control voltage via the utility model after on the control of controlled circuit can controlled voltage self fuctuation within a narrow range impact; can not make controlled circuit produce the misoperation phenomenon; realized the under-voltage protection for control voltage; the protection precision is high; hysteresis voltage can accurately be regulated, and is easy to control, and the utility model circuit is simple; cost is low, stable and reliable operation.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model preferred embodiment.
Embodiment
As shown in Figure 1; the under-voltage protecting circuit of the utility model band return difference comprises the first divider resistance R6; the end of this first divider resistance R6 is as the input VIN+ of control voltage; the other end of this first divider resistance R6 divides two-way; one the tunnel is connected with the control utmost point of a reference source U2; another road is via the second divider resistance R7 ground connection; the anode of this a reference source U2; negative electrode respectively with ground; the negative input end of optocoupler U1 connects; the positive input terminal of this optocoupler U1 is connected with second source VCC2 via the 4th resistance R 5; this optocoupler U1 just; negative output terminal VOUT+; VOUT-is connected with the corresponding controling end of controlled circuit (not shown) respectively, is connected with the return difference circuit between the negative electrode of this a reference source U2 and the control utmost point.
Such as Fig. 1, the return difference circuit comprises positive-negative-positive triode Q1, the base stage of this positive-negative-positive triode Q1 is connected with the negative electrode of a reference source U2 via the second resistance R 3, the first diode D1, the emitter of this positive-negative-positive triode Q1 connects the first power supply VCC1, be connected with the first resistance R 2 between the emitter of this positive-negative-positive triode Q1 and the base stage, the collector electrode of this positive-negative-positive triode Q1 is connected with the control utmost point of a reference source U2 via the 3rd resistance R 1, the second diode D2.
In actual design, the first diode D1 can be made of a diode, and perhaps the first diode D1 is made of a plurality of diodes in parallels, and the first diode D1 shown in Fig. 1 is made of two diodes in parallels.Similarly, the second diode D2 is made of a diode, and perhaps the second diode D2 is made of a plurality of diodes in parallels, and the second diode D2 shown in Fig. 1 is made of two diodes in parallels.
In actual design, using NPN type triode to substitute positive-negative-positive triode Q1 in the return difference circuit shown in Fig. 1 also is fine, the return difference circuit that uses NPN type triode to consist of is similar to the return difference circuit shown in Fig. 1, belongs to well known technology, does not here describe in detail.
In actual design, such as Fig. 1, the two ends of the second divider resistance R7 can be parallel with filtering delay-time electric capacity C1, can be connected with negative feedback electric capacity C2 between the control utmost point of a reference source U2 and the negative electrode, can be connected with leakage current protection resistance R4 between the positive input terminal of optocoupler U1 and the negative input end, a reference source U2 can adopt the TL431 chip, in addition, the first power supply VCC1 is generally different from the voltage of second source VCC2 output, the first power supply VCC1 is generally the power supply of 5V, and second source VCC2 is generally the power supply about 12V.
The course of work of the present utility model is:
As shown in Figure 1, when the forward control voltage of the input VIN+ of control voltage input is elevated to certain numerical value, reached the conducting voltage of a reference source U2 via the voltage of the control utmost point of the first divider resistance R6 and the second divider resistance R7 dividing potential drop backward reference source U2 input, so a reference source U2 conducting, its conduction voltage drop is about 1.9V, the interior light-emitting diode normally of optocoupler U1 this moment, so that the triode among the optocoupler U1 is realized saturation conduction, the controlled action of controlled circuit that positive and negative output VOUT+, the VOUT-of optocoupler U1 connects.
After realizing a reference source U2 conducting, the fuctuation within a narrow range of forward control voltage can not impact the control of controlled circuit, and the utility model has designed the return difference circuit.Such as Fig. 1; after a reference source U2 conducting; the first power supply VCC1 is by the first resistance R 2; the second resistance R 3; the first diode D1 and a reference source U2 form current circuit over the ground; make the positive-negative-positive triode Q1 conducting state that reaches capacity; thereby; the voltage of the first power supply VCC1 output is by the emitter of positive-negative-positive triode Q1; collector electrode; the 3rd resistance R 1; the second diode D2 is loaded into the control of a reference source U2 and extremely goes up; form hysteresis voltage; this hysteresis voltage is controlled the conducting of a reference source U2 jointly with the dividing potential drop stack of control voltage on the second divider resistance R7 is rear; therefore; when control voltage slightly descends because of fluctuation; existence because of hysteresis voltage; a reference source U2 can not produce because of the small size decline of control voltage and turn-off action; ensured that the phenomenon of misoperation can not occur because of the jitter (fuctuation within a narrow range) of control voltage controlled circuit, has realized the under-voltage protection for control voltage.
In actual use, can change by the resistance that changes the 3rd resistance R 1 numerical values recited of hysteresis voltage, thereby return difference is control effectively.
The utility model has the advantages that:
Compare with existing input and output over under-voltage protection circuit; the utility model has dispensed operational amplifier and has been the special-purpose accessory power supply of operational amplifier power supply; and can also bring into play the function of operational amplifier; a reference source also need not special-purpose accessory power supply power supply; control voltage via the utility model after on the control of controlled circuit can controlled voltage self fuctuation within a narrow range impact; can not make controlled circuit produce the misoperation phenomenon; realized the under-voltage protection for control voltage; the protection precision is high; hysteresis voltage can accurately be regulated, and is easy to control, and the utility model circuit is simple; cost is low, stable and reliable operation.
The above is preferred embodiment of the present utility model and the know-why used thereof; for a person skilled in the art; in the situation that does not deviate from spirit and scope of the present utility model; any based on apparent changes such as the equivalent transformation on the technical solutions of the utility model basis, simple replacements, all belong within the utility model protection range.
Claims (7)
1. under-voltage protecting circuit with return difference; it is characterized in that: it comprises the first divider resistance; one end of this first divider resistance is as the input of control voltage; the other end of this first divider resistance divides two-way; one the tunnel is connected with the control utmost point of a reference source; another road is via the second divider resistance ground connection; the anode of this a reference source; negative electrode respectively with ground; the negative input end of optocoupler connects; the positive input terminal of this optocoupler is connected with second source; this optocoupler just; negative output terminal is connected with the corresponding controling end of controlled circuit respectively, is connected with the return difference circuit between the negative electrode of this a reference source and the control utmost point.
2. the under-voltage protecting circuit with return difference as claimed in claim 1 is characterized in that:
Described return difference circuit comprises the positive-negative-positive triode, the base stage of this positive-negative-positive triode is connected with the negative electrode of described a reference source via the second resistance, the first diode, the emitter of this positive-negative-positive triode connects the first power supply, be connected with the first resistance between the emitter of this positive-negative-positive triode and the base stage, the collector electrode of this positive-negative-positive triode is connected with the control utmost point of described a reference source via the 3rd resistance, the second diode.
3. the under-voltage protecting circuit with return difference as claimed in claim 1 is characterized in that:
The two ends of described the second divider resistance are parallel with filtering delay-time electric capacity.
4. the under-voltage protecting circuit with return difference as claimed in claim 1 is characterized in that:
Be connected with negative feedback electric capacity between the control utmost point of described a reference source and the negative electrode.
5. the under-voltage protecting circuit with return difference as claimed in claim 1 is characterized in that:
Be connected with leakage current protection resistance between the positive input terminal of described optocoupler and the negative input end.
6. the under-voltage protecting circuit with return difference as claimed in claim 2 is characterized in that:
Described the first diode is made of a diode, and perhaps described the first diode is made of a plurality of diodes in parallels;
Described the second diode is made of a diode, and perhaps described the second diode is made of a plurality of diodes in parallels.
7. such as each described under-voltage protecting circuit with return difference in the claim 1 to 6, it is characterized in that:
Described a reference source is the TL431 chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220540141 CN202917946U (en) | 2012-10-19 | 2012-10-19 | Under-voltage protection circuit with return difference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220540141 CN202917946U (en) | 2012-10-19 | 2012-10-19 | Under-voltage protection circuit with return difference |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202917946U true CN202917946U (en) | 2013-05-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220540141 Expired - Fee Related CN202917946U (en) | 2012-10-19 | 2012-10-19 | Under-voltage protection circuit with return difference |
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| CN (1) | CN202917946U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103997199A (en) * | 2014-05-28 | 2014-08-20 | 合肥华耀电子工业有限公司 | Active power factor correction circuit with fault detection function |
| CN107395136A (en) * | 2017-08-31 | 2017-11-24 | 成都四威功率电子科技有限公司 | A kind of protection circuit applied to gallium nitride and GaAs Power amplifier |
| RU226931U1 (en) * | 2024-06-04 | 2024-06-28 | Общество с ограниченной ответственностью "ИГплюс" | Microphone with protection against electrical damage |
-
2012
- 2012-10-19 CN CN 201220540141 patent/CN202917946U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103997199A (en) * | 2014-05-28 | 2014-08-20 | 合肥华耀电子工业有限公司 | Active power factor correction circuit with fault detection function |
| CN107395136A (en) * | 2017-08-31 | 2017-11-24 | 成都四威功率电子科技有限公司 | A kind of protection circuit applied to gallium nitride and GaAs Power amplifier |
| RU226931U1 (en) * | 2024-06-04 | 2024-06-28 | Общество с ограниченной ответственностью "ИГплюс" | Microphone with protection against electrical damage |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130501 Termination date: 20181019 |