CN204858531U - Excess temperature protection circuit of high accuracy - Google Patents
Excess temperature protection circuit of high accuracy Download PDFInfo
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- CN204858531U CN204858531U CN201520499320.6U CN201520499320U CN204858531U CN 204858531 U CN204858531 U CN 204858531U CN 201520499320 U CN201520499320 U CN 201520499320U CN 204858531 U CN204858531 U CN 204858531U
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Abstract
The utility model provides an excess temperature protection circuit of high accuracy, including alternating current input end, alternating current input end and fuse, transformer T1's primary is parallelly connected, transformer T1's secondary coil and rectifier element dc's input are connected, rectifier element dc's positive output end and triode Q1's collecting electrode, electric capacity C1's one end and resistance R1's one end are connected, triode Q1's base and electric capacity C2's one end, resistance R1's the other end and triode Q2's collecting electrode are connected, triode Q1's projecting pole and resistance R2's one end, resistance R3's one end, adjustable resistance rp's one end and resistance R5's one end are connected, resistance R5's the other end and resistance R6's one end, U1's power supply anode is put to fortune, diode D1's negative pole, an input of relay is connected. The utility model discloses the voltage chip is need not and steady voltage and excess temperature protection can be realized, it is with low costs.
Description
Technical field
The utility model relates to overheat protector field, particularly relates to a kind of high-precision thermal-shutdown circuit.
Background technology
Existing thermal-shutdown circuit needs voltage stabilizing, and what generally adopt is direct voltage conversion chip, and circuit is complicated, and cost is high.
Summary of the invention
The technical problems to be solved in the utility model, is to provide a kind of high-precision thermal-shutdown circuit, solves and bothers about the high problem of protective circuit cost.
The utility model is achieved in that a kind of high-precision thermal-shutdown circuit, comprise alternating current input, alternating current input and fuse, the parallel connection of primary windings of transformer T1, the secondary coil of transformer T1 is connected with the input of rectifier cell Dc, the cathode output end of rectifier cell Dc and the collector electrode of triode Q1, one end of electric capacity C1 is connected with one end of resistance R1, the base stage of triode Q1 and one end of electric capacity C2, the other end of resistance R1 is connected with the collector electrode of triode Q2, the emitter of triode Q1 and one end of resistance R2, one end of resistance R3, one end of variable resistor Rp is connected with one end of resistance R5, the other end of resistance R5 and one end of resistance R6, the power supply anode of amplifier U1, the negative pole of diode D1, one input of relay connects, the cathode output end of rectifier cell Dc and the positive pole of voltage-stabiliser tube Ds, the other end of diode C1, the other end of diode C2, one end of resistance R4, the emitter of triode Q3, one end of thermistor Rt, one end of resistance R7 is connected with the power supply negative terminal of amplifier U1, the base stage of triode Q2 is connected with the other end of the other end of resistance R3 and resistance R4, the emitter of triode Q2 is connected with the other end of the negative pole of voltage-stabiliser tube Ds and resistance R2, the other end of variable resistor Rp is connected with the other end of thermistor Rt and the in-phase input end of amplifier U1, the other end of resistance R6 is connected with the other end of resistance R7 and the inverting input of amplifier U1, the output of amplifier U1 is connected with one end of resistance R8, the other end of resistance R8 is connected with the base stage of triode Q3, the collector electrode of triode Q3 is connected with another input of the positive pole of diode D1 and relay.
The utility model tool has the following advantages: can realize voltage stabilizing and overheat protector without the need to voltage chips, cost is low.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present utility model.
Embodiment
By describing technology contents of the present utility model, structural feature in detail, realized object and effect, accompanying drawing is coordinated to be explained in detail below in conjunction with execution mode.
Refer to Fig. 1, the utility model provides a kind of high-precision thermal-shutdown circuit, comprise alternating current input, alternating current input and fuse, the parallel connection of primary windings of transformer T1, the secondary coil of transformer T1 is connected with the input of rectifier cell Dc, the cathode output end of rectifier cell Dc and the collector electrode of triode Q1, one end of electric capacity C1 is connected with one end of resistance R1, the base stage of triode Q1 and one end of electric capacity C2, the other end of resistance R1 is connected with the collector electrode of triode Q2, the emitter of triode Q1 and one end of resistance R2, one end of resistance R3, one end of variable resistor Rp is connected with one end of resistance R5, the other end of resistance R5 and one end of resistance R6, the power supply anode of amplifier U1, the negative pole of diode D1, one input of relay connects, the cathode output end of rectifier cell Dc and the positive pole of voltage-stabiliser tube Ds, the other end of diode C1, the other end of diode C2, one end of resistance R4, the emitter of triode Q3, one end of thermistor Rt, one end of resistance R7 is connected with the power supply negative terminal of amplifier U1, the base stage of triode Q2 is connected with the other end of the other end of resistance R3 and resistance R4, the emitter of triode Q2 is connected with the other end of the negative pole of voltage-stabiliser tube Ds and resistance R2, the other end of variable resistor Rp is connected with the other end of thermistor Rt and the in-phase input end of amplifier U1, the other end of resistance R6 is connected with the other end of resistance R7 and the inverting input of amplifier U1, the output of amplifier U1 is connected with one end of resistance R8, the other end of resistance R8 is connected with the base stage of triode Q3, the collector electrode of triode Q3 is connected with another input of the positive pole of diode D1 and relay.
Wherein, this circuit is divided into a voltage stabilizing circuit and a control unit circuit.The overheat protector Temperature numerical of circuit can utilize adjustable resistance Rp to adjust.
(1) obtain after the filter action that the direct-current working volts voltage (measurement point 1) of voltage stabilizing circuit is provided by bridge rectifier and the electric capacity C1 of Dc by alternating current.In circuit, Q1 forms the effect of emitter follower.Resistance R3, R4 play dividing potential drop effect to the voltage of 2 of test.Resistance R2 plays the effect of Limited Current.Triode Q2 forms an amplifier circuit.The collector voltage of Q2 outputs to the ground level of Q1.If it is that the induced voltage after T1 also declines that alternating voltage declines, the voltage so through Dc also declines.Electric current now through Q1 increases, and the voltage of measurement point 2 is reduced, and then causes the base voltage of Q2 to reduce.Because the emitter voltage of Q2 is clamped down on by voltage stabilizing didoe Ds, so its emitter voltage is constant.So the voltage difference of the base-emitter of Q2 reduces, electric current subtracts thereupon, and collector voltage is increased.So the base current of Q1 increases, collector voltage increases, and reaches the effect of voltage stabilizing.If alternating voltage raises, the pressure stabilization function of this circuit so in like manner can be derived.
(2) U1 is a discharge circuit.When ambient temperature is lower than the temperature preset, the resistance of thermistor Rt becomes large, makes the positive input voltage of U1 higher than its reverse inter-input-ing voltage.So the output voltage of U1 is high, drive triode Q3 conducting, and then relay adhesive, whole circuit runs well.If when external voltage has exceeded the temperature preset, the resistance value of Rt has reduced, and then the reverse inter-input-ing voltage of U1 is higher than its positive input voltage, and now the output voltage of U1 is low.The output voltage of U1 is low, causes Q3 to enter cut-off state.Now relay not adhesive, circuit shuts down, and prevents temperature overheating, plays temperature protection effect.
The foregoing is only embodiment of the present utility model; not thereby scope of patent protection of the present utility model is limited; every utilize the utility model specification and accompanying drawing content to do equivalent structure or equivalent flow process conversion; or be directly or indirectly used in other relevant technical fields, be all in like manner included in scope of patent protection of the present utility model.
Claims (1)
1. a high-precision thermal-shutdown circuit, it is characterized in that: comprise alternating current input, alternating current input and fuse, the parallel connection of primary windings of transformer T1, the secondary coil of transformer T1 is connected with the input of rectifier cell Dc, the cathode output end of rectifier cell Dc and the collector electrode of triode Q1, one end of electric capacity C1 is connected with one end of resistance R1, the base stage of triode Q1 and one end of electric capacity C2, the other end of resistance R1 is connected with the collector electrode of triode Q2, the emitter of triode Q1 and one end of resistance R2, one end of resistance R3, one end of variable resistor Rp is connected with one end of resistance R5, the other end of resistance R5 and one end of resistance R6, the power supply anode of amplifier U1, the negative pole of diode D1, one input of relay connects, the cathode output end of rectifier cell Dc and the positive pole of voltage-stabiliser tube Ds, the other end of diode C1, the other end of diode C2, one end of resistance R4, the emitter of triode Q3, one end of thermistor Rt, one end of resistance R7 is connected with the power supply negative terminal of amplifier U1, the base stage of triode Q2 is connected with the other end of the other end of resistance R3 and resistance R4, the emitter of triode Q2 is connected with the other end of the negative pole of voltage-stabiliser tube Ds and resistance R2, the other end of variable resistor Rp is connected with the other end of thermistor Rt and the in-phase input end of amplifier U1, the other end of resistance R6 is connected with the other end of resistance R7 and the inverting input of amplifier U1, the output of amplifier U1 is connected with one end of resistance R8, the other end of resistance R8 is connected with the base stage of triode Q3, the collector electrode of triode Q3 is connected with another input of the positive pole of diode D1 and relay.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520499320.6U CN204858531U (en) | 2015-07-11 | 2015-07-11 | Excess temperature protection circuit of high accuracy |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520499320.6U CN204858531U (en) | 2015-07-11 | 2015-07-11 | Excess temperature protection circuit of high accuracy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204858531U true CN204858531U (en) | 2015-12-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520499320.6U Expired - Fee Related CN204858531U (en) | 2015-07-11 | 2015-07-11 | Excess temperature protection circuit of high accuracy |
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| Country | Link |
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| CN (1) | CN204858531U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111562806A (en) * | 2020-05-18 | 2020-08-21 | 西安拓尔微电子有限责任公司 | Reference source circuit for realizing low temperature coefficient voltage and current on CMOS (complementary metal oxide semiconductor) process |
-
2015
- 2015-07-11 CN CN201520499320.6U patent/CN204858531U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111562806A (en) * | 2020-05-18 | 2020-08-21 | 西安拓尔微电子有限责任公司 | Reference source circuit for realizing low temperature coefficient voltage and current on CMOS (complementary metal oxide semiconductor) process |
| CN111562806B (en) * | 2020-05-18 | 2024-06-04 | 拓尔微电子股份有限公司 | Reference source circuit for realizing low temperature coefficient voltage and current in CMOS process |
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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: 20151209 Termination date: 20160711 |