CN207067837U - A kind of thermal-shutdown circuit based on a reference source - Google Patents
A kind of thermal-shutdown circuit based on a reference source Download PDFInfo
- Publication number
- CN207067837U CN207067837U CN201721006298.2U CN201721006298U CN207067837U CN 207067837 U CN207067837 U CN 207067837U CN 201721006298 U CN201721006298 U CN 201721006298U CN 207067837 U CN207067837 U CN 207067837U
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- CN
- China
- Prior art keywords
- shunt regulator
- adjustable accurate
- triode
- accurate shunt
- thermal
- Prior art date
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Abstract
The utility model belongs to technical field of electronic control.The purpose of this utility model is to provide a kind of thermal-shutdown circuit based on a reference source, the protection circuit includes end driving triode, the break-make of end driving triode is controlled by adjustable accurate shunt regulator, voltage-stabiliser tube is provided between the base stage of end driving triode and the backward end of adjustable accurate shunt regulator, the thermistor in parallel between the controlled stage of adjustable accurate shunt regulator and positive pole, the controlled stage of adjustable accurate shunt regulator is connected by the first divider resistance with+5V voltages, the backward end of adjustable accurate shunt regulator is connected by the second divider resistance with power supply.The beneficial effects of the utility model are：This can be applied in some control circuits for not needing amplifier using the thermal-shutdown circuit of benchmark, can effectively reduce cloth plate suqare, return difference value can be adjusted flexibly for the return difference circuit of design, to adapt to different overheat protector conditions.
Description
Technical field
The utility model belongs to technical field of electronic control, and in particular to a kind of thermal-shutdown circuit based on a reference source.
Background technology
OTP circuits are usually used in power electronics and drive control field, the method that commonly used thermistor, amplifier compare.
But in some specific circuit designs, due to being limited by plate face area, it is desirable to reduce the use of power amplifier module as far as possible, therefore
It is necessary to provide a kind of replacement circuit to adapt to specific actual design.
The content of the invention
The purpose of this utility model is to provide one kind can carry out excess temperature guarantor in real time on the premise of inapplicable power amplifier module
The circuit of shield.
To realize above-mentioned technical purpose, the technical solution adopted in the utility model is：A kind of excess temperature based on a reference source is protected
Protection circuit, it is characterised in that：The protection circuit includes being used for the NPN type end driving triode for realizing the output of OTP function signals,
The break-make of end driving triode is controlled by adjustable accurate shunt regulator, when adjustable accurate shunt regulator is connected,
End driving triode is closed, and when adjustable accurate shunt regulator disconnects, end driving triode is connected, and is driven in end
Voltage-stabiliser tube is provided between the base stage of triode and the backward end of adjustable accurate shunt regulator, in adjustable accurate parallel voltage-stabilizing
Thermistor in parallel between the controlled stage of device and positive pole, the controlled stage of adjustable accurate shunt regulator pass through the first divider resistance
It is connected with supply voltage, the backward end of adjustable accurate shunt regulator is connected by the second divider resistance with power supply.
Further, in addition to return difference circuit, described return difference circuit are described including controlling triode and drawing high resistance
Control the base stage Continuity signal of triode to be exported by the positive pole of voltage-stabiliser tube, control the colelctor electrode of triode by drawing high resistance and electricity
Source voltage connection.
Further, in addition to RC filter circuits, described RC filter circuits include filter resistance and the filter being serially connected
Ripple electric capacity, be grounded after the radiation of the negative pole of filter capacitor and end driving triode is extremely in parallel, the other end of filter resistance with surely
The positive pole connection of pressure pipe.
The beneficial effects of the utility model are：The thermal-shutdown circuit based on a reference source can be applied need not at some
In the control circuit of amplifier, cloth plate suqare can be effectively reduced, return difference value can be adjusted flexibly for the return difference circuit of design,
To adapt to different overheat protector conditions.
Brief description of the drawings
Accompanying drawing 1 is a kind of physical circuit figure of the thermal-shutdown circuit based on a reference source.
Embodiment
Below in conjunction with the accompanying drawings and embodiment is described in detail to the thermal-shutdown circuit based on a reference source.
As shown in Figure 1, a kind of thermal-shutdown circuit based on a reference source, Vcc are system power source voltage, and REF is 5V's
Chip reference voltage, U6 are the adjustable accurate shunt regulator of 2.5V benchmark, and its model may be selected to be：HA17431H、
TL431, TL432, ZTL431AH6TA, ZTL431BE5TA, UTCTL431L, ZTL431BFFTA etc., in this example, select
TL431, RT are negative tempperature coefficient thermistor.When module temperature is relatively low, because RT resistance is far above R9, U6 3 pin electricity
Pressure is higher than its reference voltage 2.5V, and U6 conductings, close to zero, voltage-stabiliser tube U5 ends 2 pin current potentials.With the rise of module temperature,
RT resistances can reduce rapidly, and when resistance is less than target resistance, U6 3 pin voltages are less than reference voltage 2.5V, U6 cut-offs, 2 pin
Current potential is high level, voltage-stabiliser tube U5 conductings, Q6 conductings, exports low level by SS pins, realizes OTP functions.
As shown in Figure 1, it have also been devised return difference circuit in the present embodiment simultaneously.The design of return difference circuit by Q5 and
R13 is realized.After overheat protector action, module temperature gradually reduces, and RT resistances gradually rise, but due to Q5 after overheat protector
Open-minded, R13 is in parallel with RT, so U6 3 pin voltages will not be higher than 2.5V reference voltages at once.By the big I for adjusting R13
With the size of adjusting return difference.U5 is 5.1V voltage-stabiliser tubes, can prevent Q6 from misleading, R11, C10 combine to form RC filter circuits.
The resistance value for being set by adjusting R9 that the circuit crosses warm spot is achieved.It is specific as follows：
As temperature raises, resistance RT resistance decrease, the excess temperature when its both end voltage is equal to U6 reference voltage 2.5V
Protection, design RT0For thermistor overheat protector when resistance.Now：
Resistance R9 can be increased and improved warm spot, reducing resistance R9 reduced warm spot.
The resistance value for being set by adjusting R13 of the circuit return difference value is achieved.It is specific as follows：
When circuit carries out overheat protector, Q5 conductings are in parallel with RT equivalent to resistance R13, when its both end voltage reaches
Protection circuit is recovered during 2.5V, designs RT1The resistance of thermistor during to recover, now：
Can be by changing resistance R13 resistance adjusting return difference, increase R13 then reduces return difference, reduces R13 and then increases back
Difference.
Claims (3)
- A kind of 1. thermal-shutdown circuit based on a reference source, it is characterised in that：The protection circuit includes being used to realize that OTP functions are believed Number output NPN type end driving triode, end driving triode break-make by adjustable accurate shunt regulator control, when When adjustable accurate shunt regulator is connected, end driving triode is closed, when adjustable accurate shunt regulator disconnects, end End driving triode is connected, and is provided between the base stage of end driving triode and the backward end of adjustable accurate shunt regulator Voltage-stabiliser tube, the thermistor in parallel between the controlled stage of adjustable accurate shunt regulator and positive pole, adjustable accurate are in parallel steady The controlled stage of depressor is connected by the first divider resistance with+5V voltages, and the backward end of adjustable accurate shunt regulator passes through Two divider resistances are connected with power supply.
- A kind of 2. thermal-shutdown circuit based on a reference source according to claim 1, it is characterised in that：Also include return difference electricity Road, described return difference circuit include control triode and draw high resistance, and the base stage Continuity signal of described control triode is by steady The positive pole output of pressure pipe, the colelctor electrode of control triode pair are connected by drawing high resistance with+5V voltages.
- A kind of 3. thermal-shutdown circuit based on a reference source according to claim 1, it is characterised in that：Also include RC to filter Circuit, described RC filter circuits include the filter resistance and filter capacitor being serially connected, and negative pole and the end of filter capacitor are driven It is connected after the radiation of dynamic triode extremely parallel connection with earth terminal, the other end of filter resistance and the positive pole of voltage-stabiliser tube connect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721006298.2U CN207067837U (en) | 2017-08-13 | 2017-08-13 | A kind of thermal-shutdown circuit based on a reference source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721006298.2U CN207067837U (en) | 2017-08-13 | 2017-08-13 | A kind of thermal-shutdown circuit based on a reference source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207067837U true CN207067837U (en) | 2018-03-02 |
Family
ID=61514844
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721006298.2U Expired - Fee Related CN207067837U (en) | 2017-08-13 | 2017-08-13 | A kind of thermal-shutdown circuit based on a reference source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN207067837U (en) |
-
2017
- 2017-08-13 CN CN201721006298.2U patent/CN207067837U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| 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: 20180302 Termination date: 20180813 |