CN106602512A - Overheating protection circuit based on p-n junction forward voltage drop temperature characteristic - Google Patents
Overheating protection circuit based on p-n junction forward voltage drop temperature characteristic Download PDFInfo
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- CN106602512A CN106602512A CN201611261403.7A CN201611261403A CN106602512A CN 106602512 A CN106602512 A CN 106602512A CN 201611261403 A CN201611261403 A CN 201611261403A CN 106602512 A CN106602512 A CN 106602512A
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- Prior art keywords
- resistance
- electric capacity
- voltage
- pnp triode
- junction
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/047—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using a temperature responsive switch
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
- H02H7/222—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for switches
Abstract
An overheating protection circuit based on a p-n junction forward voltage drop temperature characteristic comprises a voltage conversion circuit and an overheating control signal conversion circuit. The heating sensing element of the overheating control signal conversion circuit is a PNP triode, when the temperature detected by the PNP triode does not exceed a setting value, the emitter junction voltage set by the circuit for the emitter of the PNP triode in advance does not reach the minimum voltage of the conduction, the emitter of the PNP triode is located at a closing state, and a comparator outputs high level to control the normal work of the module required being protected; when the temperature detected by the PNP triode exceeds the setting value, because the emitter junction p-n junction forward voltage has the negative temperature characteristic, the emitter junction conduction voltage of the thermal detection triode is dropped to the circuit preset voltage to allow the emitter to be conducted, and the comparator overturns the output low level to control the closing of the module required being protected to play a thermal protection effect. The voltage conversion circuit employs a high-precision and low-temperature drift reference circuit which is taken as the power supply of the overheating control signal conversion circuit so as to improve the accuracy of the overheating protection.
Description
Technical field
The invention belongs to overheating protection circuit technical field, and in particular to a kind of based on PN junction forward voltage drop temperature characterisitic
Overheating protection circuit.
Background technology
In Switching Power Supply and power drive electronic module, because dissipated power is often than larger, when ambient temperature it is too high
Or in the case of there is internal short-circuit, power consumption can be increased dramatically, and cause internal components to damage because temperature is too high.On preventing
The occurrence of stating, typically both increases overheating protection circuit in inside modules.Conventional overtemperature protection circuit mainly passes through
Critesistor, temperature switch and temperature fuse etc. are realizing.In existing excess temperature protection method, critesistor and temperature switch
Non-linear serious, the element concordance of relation that detection method all has resistance and temperature is poor with interchangeability, element is easy to be aging, stably
Property difference the shortcomings of.And temperature fuse exists after excess temperature disappearance in addition to the disadvantages mentioned above with critesistor and temperature switch, also
Expendable shortcoming.
The content of the invention
The technical problem to be solved is to provide a kind of positive based on PN junction for shortcoming of the prior art
The overheating protection circuit based on PN junction forward voltage drop temperature characterisitic that pressure drop has a principle of negative temperature characteristic and designs, the present invention
The voltage conversion circuit of circuit adopts high accuracy, the reference circuit of Low Drift Temperature, used as the power supply of excess temperature control signal change-over circuit
Power supply, it is ensured that the stability of temperature detection PNP triode emitter stage institute preset voltage, so as to improve the accurate of overtemperature protection
Property.
Technical problem to solve the present invention is adopted the following technical scheme that：
A kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic, is turned by voltage conversion circuit, excess temperature control signal
Circuit composition is changed, the heat sensor in excess temperature control signal change-over circuit is a PNP triode, when PNP triode is detected
Temperature not less than setting value when, circuit is the minimum voltage that its preset transmitting junction voltage is not up to its conducting, and it is in pass
Disconnected state, comparator exports high level to control required protection module normal work；When the temperature that PNP triode is detected exceedes
During setting value, the characteristics of have negative temperature characteristic due to PNP triode emitter junction PN junction forward voltage, hot detection transistor is sent out
Penetrate knot conducting voltage and drop to circuit presets voltage so as to turn on, comparator upset exports low level to control to turn off required guarantor
The module of shield, plays heat protective effect.
The voltage conversion circuit is made up of the first IC 1, the first electric capacity C1, the second electric capacity C2, and first is electric
Hold 1 foot of first IC 1 of termination of C1 to power voltage input terminal, it is electric that 2 feet of the first IC 1 connect second
Hold one end of C2, the 3 feet ground connection of the first electric capacity C1, the other end of the second electric capacity C2 and the first IC 1.
The excess temperature control signal change-over circuit is by PNP triode T1, first resistor R1, second resistance R2, the 3rd electric
Resistance R3*, the 4th resistance R4, the 5th resistance R5, the 3rd electric capacity C3, the 4th electric capacity C4, the second IC 2, the 6th resistance R6
Composition；The emitter stage of PNP triode T1 and one end of 3rd resistor R3*, 8 feet of the second IC 2, the 6th resistance R6
One end is connected and is connected to 2 feet of the first IC 1, and another 1 foot for being connected to the first IC 1 of the 6th resistance R6 is extremely
Control signal output, the colelctor electrode of PNP triode T1 connects one end of first resistor R1, the other end of first resistor R1 and second
One end of resistance R2, one end of the 4th electric capacity C4 are mutually connected to 2 feet of the second IC 2, and the base stage of PNP triode T1 connects
The other end and one end of the 4th resistance R4 in 3rd resistor R3*, the other end of the 4th resistance R4 and one end of the 5th resistance R5,
One end of 3rd electric capacity C3 is mutually connected to 3 feet of the second IC 2, and the other end of second resistance R2 is another with the 5th resistance R5's
One end, the other end of the 3rd electric capacity C3, the other end of the 4th electric capacity C4 are connected and are connected to ground.
The PNP triode temperature often rises 1 DEG C, and PN junction conducting voltage declines 2mV.
Circuit on the basis of first IC 1, its model AD581, the first IC 2 is comparator,
Its model LM193.
In the excess temperature control signal change-over circuit of circuit of the present invention, excess temperature detecting element is from the high PNP of technology stability
Audion semiconductor device, using its emitter stage（PN junction）Conducting voltage has the principle of negative temperature characteristic to realize the inspection of excess temperature
Survey, the overtemperature protection for being applied to module using this scheme makes it have that protection sensitive, high precision, concordance be good, good stability
The features such as.Heat sensor is a PNP triode in the present invention, when the temperature that it is detected is not less than setting value, because of circuit
For the minimum voltage that its preset transmitting junction voltage is not up to its conducting, so it is off state, comparator output is high electric
Put down with protection module normal work needed for controlling, when the temperature that audion is detected exceedes setting value, because PNP triode is sent out
Penetrate knot（PN junction）The characteristics of forward voltage has negative temperature characteristic（Temperature often rises 1 DEG C, and PN junction conducting voltage declines 2mV）, heat
The emitter junction conducting voltage of detection transistor drops to circuit presets voltage so as to turn on, comparator upset output low level with
The module of protection, plays heat protective effect needed for control shut-off.While in order to ensure hot detection transistor emitter junction preset voltage
Stability, we employ output voltage high precision, the reference circuit of Low Drift Temperature is powered for circuit, so as to improve temperature excess temperature
The accuracy of protection.The voltage conversion circuit of circuit of the present invention adopts high accuracy, the reference circuit of Low Drift Temperature, used as excess temperature control
The power supply of signaling conversion circuit, this solution ensures stablizing for temperature detection PNP triode emitter stage institute's preset voltage
Property, so as to improve the accuracy of overtemperature protection.
Description of the drawings
Fig. 1 is principle of the invention block diagram.
Specific embodiment
Below in conjunction with the accompanying drawings and embodiment is described in detail to the technical scheme of patent of the present invention.
As shown in figure 1, a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic, by voltage conversion circuit,
Excess temperature control signal change-over circuit is constituted.The voltage conversion circuit be by the first IC 1, the first electric capacity C1, second
Electric capacity C2 is constituted:The one of first electric capacity C1 terminates 1 foot of the first IC 1 to power voltage input terminal, the first integrated electricity
2 feet of road IC1 connect one end of the second electric capacity C2, the first electric capacity C1, the other end of the second electric capacity C2 and the first IC 1
3 feet are grounded.The excess temperature control signal change-over circuit is by the first audion T1, first resistor R1, second resistance R2, the 3rd electric
Resistance R3*, the 4th resistance R4, the 5th resistance R5, the 3rd electric capacity C3, the 4th electric capacity C4, the second IC 2, the 6th resistance R6
Composition：The emitter stage of the first audion T1 and one end of 3rd resistor R3*, 8 feet of the second IC 2, the 6th resistance R6
One end be connected and be connected to 2 feet of the first IC 1, another 1 foot for being connected to the first IC 1 of the 6th resistance R6
To control signal output, the colelctor electrode of the first audion T1 connects one end of first resistor R1, the other end of first resistor R1 with
One end of second resistance R2, one end of the 4th electric capacity C4 are mutually connected to 2 feet of the second IC 2, the base of the first audion T1
Pole is connected on one end of the other end of 3rd resistor R3* and the 4th resistance R4, the other end of the 4th resistance and the 5th resistance R5's
One end, one end of the 3rd electric capacity C3 are mutually connected to 3 feet of the second IC 2, the other end of second resistance R2 and the 5th resistance
The other end of R5, the other end of the 3rd electric capacity C3, the other end of the 4th electric capacity are connected and are connected to ground.
The operation principle of patent of invention：The DC voltage Jing high precision reference circuits of power input 15V-30V first are changed into
Accurately 10V voltages with to rear class excess temperature control signal change-over circuit provide power supply.It is first in excess temperature control signal change-over circuit
First Jing R3*, R4, R5 are respectively to emitter stage, the preset electricity of the foot of inverting input 2 of comparator IC2 of temperature detection PNP triode T1
Pressure, gives the emitter junction of PNP triode T1 preset voltage（That is the voltage at resistance R3* two ends）As set overtemperature protection
Required minimum voltage when PNP triode T1 emitter junction is turned on during temperature spot, and give 2 feet of IC2 preset voltage（That is R5
On voltage）To there is threshold voltage when comparator overturns during overtemperature protection.In not up to set overtemperature protection
During temperature spot, because the circuit emitter voltage preset for temperature detection PNP triode T1 emitter stage is not up to its conducting most
Low-voltage, so it is off state, comparator exports high level to control required protection module normal work, when temperature inspection
When the temperature that survey PNP triode T1 is gathered exceedes the overtemperature protection temperature spot of setting, because PN junction forward voltage has subzero temperature
The characteristics of degree characteristic（Temperature often rises 1 DEG C, and PN junction conducting voltage declines 2mV）, heat detection PNP triode T1 emitter stage electric conduction
Pressure drops to the preset voltage of circuit so as to turn on, so that the voltage obtained on 3 feet of comparator IC2 is more than comparator
There is upset output low level with the module of protection needed for controlling to turn off in the preset threshold voltage of 2 feet of IC2, comparator, play
Heat protective effect.
The selection of patent component devices of the present invention：Circuit on the basis of first IC 1, its model AD581, second
IC 2 is comparator, and its model LM193, audion T1, model 3CG200E, electric capacity C1, C2, C3, C4 are
Patch capacitor, the capacitance of C1 is 1 μ F, and the capacitance of C2 is 0.1 μ F, and the capacitance of C3, C4 is 0.001 μ F, the precision of all electric capacity
≤15%；Resistance R1=5.6k Ω, R2=150 Ω, R3*=260 Ω, R4=10.2k Ω, R5=105 Ω, R6=10k Ω, own
Resistance is printed resistor, precision≤5%.
Claims (5)
1. a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic, it is characterised in that：By voltage conversion circuit, mistake
Temperature control signaling conversion circuit is constituted, and the heat sensor in excess temperature control signal change-over circuit is a PNP triode, works as PNP
When the temperature that audion is detected is not less than setting value, circuit is the minimum electricity that its preset transmitting junction voltage is not up to its conducting
Pressure, it is off state, and comparator exports high level to control required protection module normal work；When PNP triode is examined
When the temperature of survey exceedes setting value, the characteristics of there is negative temperature characteristic due to PNP triode emitter junction PN junction forward voltage, heat inspection
The emitter junction conducting voltage for surveying audion drops to circuit presets voltage so as to turn on, and comparator upset exports low level to control
The module of protection, plays heat protective effect needed for system shut-off.
2. a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic according to claim 1, its feature exists
In：The voltage conversion circuit is made up of the first IC 1, the first electric capacity C1, the second electric capacity C2, the first electric capacity C1's
To power voltage input terminal, 2 feet of the first IC 1 connect the second electric capacity C2's to 1 foot of one the first IC 1 of termination
One end, the 3 feet ground connection of the first electric capacity C1, the other end of the second electric capacity C2 and the first IC 1.
3. a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic according to claim 1 and 2, its feature
It is：The excess temperature control signal change-over circuit is by PNP triode T1, first resistor R1, second resistance R2,3rd resistor
R3*, the 4th resistance R4, the 5th resistance R5, the 3rd electric capacity C3, the 4th electric capacity C4, the second IC 2, the 6th resistance R6 groups
Into；The emitter stage of PNP triode T1 and one end of 3rd resistor R3*, 8 feet of the second IC 2, the one of the 6th resistance R6
End is connected and is connected to 2 feet of the first IC 1, and another 1 foot for being connected to the first IC 1 of the 6th resistance R6 is to control
Signal output part processed, the colelctor electrode of PNP triode T1 connects one end of first resistor R1, and the other end of first resistor R1 is electric with second
One end of resistance R2, one end of the 4th electric capacity C4 are mutually connected to 2 feet of the second IC 2, and the base stage of PNP triode T1 is connected on
One end of one end of the other end of 3rd resistor R3* and the 4th resistance R4, the other end of the 4th resistance R4 and the 5th resistance R5,
One end of three electric capacity C3 is mutually connected to 3 feet of the second IC 2, and the other end of second resistance R2 is another with the 5th resistance R5's
End, the other end of the other end of the 3rd electric capacity C3, the 4th electric capacity C4 are connected and are connected to ground.
4. a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic according to claim 1, its feature exists
In：The PNP triode temperature often rises 1 DEG C, and PN junction conducting voltage declines 2mV.
5. a kind of overheating protection circuit based on PN junction forward voltage drop temperature characterisitic according to claim 1 or 4, its feature
It is：Circuit on the basis of first IC 1, its model AD581, the first IC 2 is comparator, its
Model LM193.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611261403.7A CN106602512A (en) | 2016-12-30 | 2016-12-30 | Overheating protection circuit based on p-n junction forward voltage drop temperature characteristic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611261403.7A CN106602512A (en) | 2016-12-30 | 2016-12-30 | Overheating protection circuit based on p-n junction forward voltage drop temperature characteristic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106602512A true CN106602512A (en) | 2017-04-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611261403.7A Pending CN106602512A (en) | 2016-12-30 | 2016-12-30 | Overheating protection circuit based on p-n junction forward voltage drop temperature characteristic |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106602512A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107577261A (en) * | 2017-09-25 | 2018-01-12 | 深圳市中孚能电气设备有限公司 | A kind of temp control switch circuit |
| CN112886802A (en) * | 2021-01-15 | 2021-06-01 | 深圳市群芯科创电子有限公司 | Secondary side synchronous rectification circuit with thermal protection function and electronic equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2446186A (en) * | 2007-01-30 | 2008-08-06 | Jonathan Champion | Electrical safety device |
| CN102055169A (en) * | 2009-10-28 | 2011-05-11 | 中国科学院微电子研究所 | Over-temperature protection circuit |
| CN104967095A (en) * | 2015-07-29 | 2015-10-07 | 电子科技大学 | Over-temperature protection circuit |
| CN204835506U (en) * | 2015-04-20 | 2015-12-02 | 中国计量学院 | Lithium cell charging protection circuit |
| US20160336309A1 (en) * | 2015-05-11 | 2016-11-17 | Rohm Co., Ltd. | Overheat protection circuit, and semiconductor integrated circuit device and vehicle therewith |
-
2016
- 2016-12-30 CN CN201611261403.7A patent/CN106602512A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2446186A (en) * | 2007-01-30 | 2008-08-06 | Jonathan Champion | Electrical safety device |
| CN102055169A (en) * | 2009-10-28 | 2011-05-11 | 中国科学院微电子研究所 | Over-temperature protection circuit |
| CN204835506U (en) * | 2015-04-20 | 2015-12-02 | 中国计量学院 | Lithium cell charging protection circuit |
| US20160336309A1 (en) * | 2015-05-11 | 2016-11-17 | Rohm Co., Ltd. | Overheat protection circuit, and semiconductor integrated circuit device and vehicle therewith |
| CN104967095A (en) * | 2015-07-29 | 2015-10-07 | 电子科技大学 | Over-temperature protection circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107577261A (en) * | 2017-09-25 | 2018-01-12 | 深圳市中孚能电气设备有限公司 | A kind of temp control switch circuit |
| CN112886802A (en) * | 2021-01-15 | 2021-06-01 | 深圳市群芯科创电子有限公司 | Secondary side synchronous rectification circuit with thermal protection function and electronic equipment |
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| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
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| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170426 |
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| RJ01 | Rejection of invention patent application after publication |