CN204145283U - A kind of derate temperature protection circuit - Google Patents
A kind of derate temperature protection circuit Download PDFInfo
- Publication number
- CN204145283U CN204145283U CN201420448341.0U CN201420448341U CN204145283U CN 204145283 U CN204145283 U CN 204145283U CN 201420448341 U CN201420448341 U CN 201420448341U CN 204145283 U CN204145283 U CN 204145283U
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- resistor
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- operational amplifier
- power supply
- thermistor
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- 238000005070 sampling Methods 0.000 claims abstract description 4
- 239000003990 capacitor Substances 0.000 claims description 4
- 230000000087 stabilizing effect Effects 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 abstract description 2
- 239000003381 stabilizer Substances 0.000 abstract 3
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
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- Emergency Protection Circuit Devices (AREA)
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Abstract
The utility model discloses a kind of derate temperature protection circuit, comprise operational amplifier, voltage-stabiliser tube, thermistor, diode and resistance; Wherein, power supply is by thermistor and the first electric resistance partial pressure ground connection; The tie point of thermistor and resistance is connected the negative pole of voltage-stabiliser tube by the second resistance; The end of oppisite phase of operational amplifier connects positive pole and the sampling resistor of voltage-stabiliser tube respectively, and in-phase end connects reference circuit, and output connects reverse diode.The utility model can make power supply reduce power output gradually with the rising of ambient temperature, realizes derate and exports, and ensures the work that power supply is reliable and stable in hot environment for a long time.
Description
Technical Field
The utility model relates to a derating temperature protection circuit belongs to switching power supply technical field.
Background
With the rapid development of the LED driving power supply, product performance parameters, product reliability design, protection of key devices and the like are highly emphasized by a plurality of manufacturers, more research and development efforts are put into, and the LED driving power supply is developed greatly. Due to the continuous emergence of new technologies, market competition is increasingly developed towards specialization, high reliability and high standard.
The over-temperature protection circuit is mainly used for judging whether the temperature is too high by detecting a switching power supply, a power device or a radiator and the like. When the switching power supply normally works, the temperature of the switching power supply generally does not exceed the critical temperature; when the switching power supply is abnormal, the temperature can rise rapidly, if the over-temperature protection circuit is not arranged, the temperature of the switching power supply can continue to rise, the switching power supply and the circuit board can be burnt when a certain temperature is reached, and fire disasters are caused when the temperature is serious. Therefore, it is desirable to provide a temperature protection circuit for a switching power supply.
In chinese utility model patent No. 201120228308.3, an overheat protection circuit for a switching power supply is disclosed. When the temperature exceeds the set critical temperature, the circuit can monitor the temperature signal, a low level signal is sent to the control chip by triggering the output end of the latch circuit, and then the control chip controls the switching power supply to stop working, so that the switching power supply is protected from over-temperature. In the actual high-temperature environment, the output power of the switching power supply is constant all the time, and the switching power supply stops working only by exceeding the critical temperature, so that the reliability of the power supply cannot be guaranteed.
Disclosure of Invention
Not enough to prior art, the utility model aims to solve the technical problem that a derating temperature protection circuit is provided. The circuit can enable the power supply to gradually reduce the output power along with the rise of the ambient temperature, and the derated output is realized.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a derating temperature protection circuit comprises an operational amplifier, a voltage regulator tube, a thermistor, a diode, a resistor and a reference circuit; wherein,
the power supply is grounded through the thermistor and the first resistor in a voltage division manner; the connecting point of the thermistor and the resistor is connected with the negative electrode of the voltage stabilizing tube through a second resistor;
the inverting terminal of the operational amplifier is respectively connected with the anode of the voltage-stabilizing tube and the sampling resistor, the non-inverting terminal of the operational amplifier is connected with the reference circuit, and the output terminal of the operational amplifier is connected with the diode in the reverse direction.
Preferably, the reference circuit is a voltage dividing circuit of a resistor; one end of the third resistor is connected with the reference voltage, and the other end of the third resistor is grounded through a parallel path of the two resistors; and the connection point of the third resistor and the parallel path is connected with the non-inverting terminal of the operational amplifier.
Preferably, the non-inverting terminal of the operational amplifier is grounded through a capacitor.
The utility model provides a derating temperature protection circuit can make the power reduce output gradually along with ambient temperature's rising, realizes derating the output, guarantees that the power is reliable and stable work in high temperature environment for a long time.
Drawings
Fig. 1 is a schematic circuit diagram of the derating temperature protection circuit provided by the present invention.
Detailed Description
The technical content of the present invention will be further explained with reference to the accompanying drawings and specific embodiments.
Referring to fig. 1, the derating temperature protection circuit provided by the present invention includes a thermistor RT1, a resistor R1, R2, R3, R4, R5, R6, R7, a capacitor C1, a voltage regulator V1, a diode V2, and an operational amplifier N1. One end of the thermistor RT1 is connected to an auxiliary power supply VDD, and the other end is grounded through a series path of the resistor R1 and the resistor R2. The connection point of the thermistor RT1 and the resistor R1 is connected with the inverting terminal of the operational amplifier N1 through the resistor R3 and the voltage regulator V1. The anode of the voltage-stabilizing tube V1 is connected with the inverting terminal, and the cathode is connected with the resistor R3. The inverting terminal of the operational amplifier is also connected with a sampling resistor R4, and the resistor is used for collecting the current signal of the load and converting the current signal into a voltage signal. The non-inverting terminal of the operational amplifier N1 is connected to the reference circuit, and to ground via the capacitor C1. The reference circuit includes resistors R5, R6, R7. The reference voltage Vref is divided by the resistor R7 and the parallel path of the resistors R5 and R6 and then grounded. The connection point of the resistor R7 and the parallel path of the resistors R5 and R6 is used as the reference voltage of the non-inverting terminal of the operational amplifier. The output end of the operational amplifier is connected with a diode V2 in the reverse direction. The diode V2 controls the switching of the current IC.
When the LED driving power supply works normally, VDD starts to be electrified. The negative temperature coefficient thermistor RT1 detects the temperature. The resistance of the thermistor RT1 gradually decreases with increasing temperature, so that the voltage division across the resistors R1 and R2 gradually increases. With the increase of the voltage division of the resistors R1 and R2, reverse voltage starts to be arranged at two ends of the voltage regulator tube. When the reverse voltage reaches a certain degree, the voltage-stabilizing tube breaks down. At this time, current starts to flow through the branch of the resistor R3, so that the voltage rise is detected at the inverting terminal of the operational amplifier N1. While the voltage at the non-inverting terminal of the reference circuit is stable. After the reference voltage of the same-phase end of the operational amplifier is compared with the voltage of the opposite-phase end of the operational amplifier and amplified, the level of the output end of the operational amplifier N1 is reduced in proportion according to the difference of the input ends, and the diode V2 is conducted in a forward bias mode. After the diode V2 is conducted, the current of the output end is controlled to change, so that the purpose of reducing the rated output is achieved. And when the temperature is relatively low and the change is not large, the voltage at the connecting point of the thermistor and the resistor R1 is low, so that the voltage stabilizing tube is conducted in the positive direction. The voltage of the inverting terminal and the non-inverting terminal of the operational amplifier has a difference, the diode V2 is cut off in the reverse direction, and the power output is maintained in a stable state.
The derating temperature protection circuit provided by the present invention has been described in detail above. Any obvious modifications to the above would be obvious to those skilled in the art, without departing from the essential spirit of the present invention, and it is intended to constitute a violation of the patent rights of the present invention and to bear the corresponding legal responsibility.
Claims (3)
1. A derating temperature protection circuit is characterized by comprising an operational amplifier, a voltage regulator tube, a thermistor, a diode, a resistor and a reference circuit; wherein,
the power supply is grounded through the thermistor and the first resistor in a voltage division manner; the connecting point of the thermistor and the resistor is connected with the negative electrode of the voltage stabilizing tube through a second resistor;
the inverting terminal of the operational amplifier is respectively connected with the anode of the voltage-stabilizing tube and the sampling resistor, the non-inverting terminal of the operational amplifier is connected with the reference circuit, and the output terminal of the operational amplifier is connected with the diode in the reverse direction.
2. The de-rated temperature protection circuit of claim 1, wherein:
the reference circuit is a voltage division circuit of a resistor; one end of the third resistor is connected with the reference voltage, and the other end of the third resistor is grounded through a parallel path of the two resistors; and the connection point of the third resistor and the parallel path is connected with the non-inverting terminal of the operational amplifier.
3. The de-rated temperature protection circuit of claim 1, wherein:
and the non-inverting end of the operational amplifier is grounded through a capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420448341.0U CN204145283U (en) | 2014-08-08 | 2014-08-08 | A kind of derate temperature protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420448341.0U CN204145283U (en) | 2014-08-08 | 2014-08-08 | A kind of derate temperature protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204145283U true CN204145283U (en) | 2015-02-04 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420448341.0U Expired - Fee Related CN204145283U (en) | 2014-08-08 | 2014-08-08 | A kind of derate temperature protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN204145283U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108092498A (en) * | 2018-02-05 | 2018-05-29 | 珠海格力电器股份有限公司 | Over-temperature protection device and method and switching power supply |
| CN109936117A (en) * | 2017-12-19 | 2019-06-25 | 海能达通信股份有限公司 | Temperature protection circuit and electronic equipment |
-
2014
- 2014-08-08 CN CN201420448341.0U patent/CN204145283U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109936117A (en) * | 2017-12-19 | 2019-06-25 | 海能达通信股份有限公司 | Temperature protection circuit and electronic equipment |
| CN108092498A (en) * | 2018-02-05 | 2018-05-29 | 珠海格力电器股份有限公司 | Over-temperature protection device and method and switching power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: Derating temperature protection circuit Effective date of registration: 20150618 Granted publication date: 20150204 Pledgee: Beijing technology business factoring Ltd. Pledgor: Beijing Tonlier Energy-saving LLC. Registration number: 2015990000483 |
|
| PLDC | Enforcement, change and cancellation of contracts on pledge of patent right or utility model | ||
| 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: 20150204 Termination date: 20170808 |