CN105490247B - A kind of thermal-shutdown circuit - Google Patents
A kind of thermal-shutdown circuit Download PDFInfo
- Publication number
- CN105490247B CN105490247B CN201510849472.9A CN201510849472A CN105490247B CN 105490247 B CN105490247 B CN 105490247B CN 201510849472 A CN201510849472 A CN 201510849472A CN 105490247 B CN105490247 B CN 105490247B
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- Prior art keywords
- temperature detecting
- resistance
- branch road
- detecting unit
- partial pressure
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- 230000005611 electricity Effects 0.000 claims description 5
- 238000001514 detection method Methods 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 description 2
- 230000001012 protector Effects 0.000 description 2
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Classifications
-
- 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
- H02H5/042—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 temperature dependent resistors
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Control Of Temperature (AREA)
Abstract
The present invention relates to a kind of thermal-shutdown circuit; including at least two temperature detecting units; and the protection circuit that the output voltage source by connecting, a divider resistance and partial pressure branch road in parallel with temperature detecting unit same number are formed; it is equipped with a switching tube on each partial pressure branch road, the tie point of the divider resistance and each partial pressure branch road is used to connect voltage output end；Each temperature detecting unit corresponds to the switching tube described in drive connection one by isolation element；Temperature threshold corresponding to each temperature detecting unit is different, and the resistance of partial pressure branch road corresponding to each temperature detecting unit is different.The circuit of the present invention, it is divided into two-stage or multi-step temperature threshold value, the protection of implementation phase formula, protects more perfect.
Description
Technical field
The present invention relates to a kind of thermal-shutdown circuit.
Background technology
Precision voltage regulator TL431, TL432, i.e. three end adjustable reference shunting sources, are frequently used for measurement and control of temperature protection circuit.
Chinese patent application such as Application No. 201020503923.6 discloses a kind of overheat protector electricity based on TL431
Road, as shown in figure 1, Rt is thermistor, resistance on the basis of Rf, Rf value is designed, when temperature changes, Rt resistance, which changes, leads
Rt and Rf partial pressure is caused to change；So as to which in design temperature, TL431 reaches reference voltage, anode cathode switched-on light emitting diodes enter
Row alarm；Or light emitting diode triggering late-class circuit is alarmed.
The circuit of such scheme can produce alarm but directly late-class circuit can not be implemented to protect, even if being protected
Shield is also directly to cut off the electricity supply, and protected mode is more rough, it is impossible to meets the needs of different levels.
The content of the invention
It is an object of the invention to provide a kind of thermal-shutdown circuit, to solve the problems, such as that existing protection is not soft enough.
To achieve the above object, the solution of the present invention includes：
A kind of thermal-shutdown circuit, including at least two temperature detecting units, and the output voltage source by connecting
(VCC2), the protection circuit that a divider resistance (R4) and partial pressure branch road in parallel with temperature detecting unit same number are formed,
A switching tube is equipped with each partial pressure branch road, the tie point of the divider resistance and each partial pressure branch road is defeated for connecting voltage
Go out end；Each temperature detecting unit corresponds to the switching tube described in drive connection one by isolation element；Each temperature inspection
Temperature threshold difference corresponding to unit is surveyed, the resistance of partial pressure branch road corresponding to each temperature detecting unit is different.
The temperature detecting unit is the temperature sensing circuit formed by precision voltage regulator, and the temperature sensing circuit includes base
Quasi- power supply (VCC1) and precision voltage regulator (U1), the reference edge connection thermistor (R1) and reference resistance of precision voltage regulator (U1)
(R10) series connection point, the output driving connecting triode (Q1) of precision voltage regulator (U1), for the moon in precision voltage regulator (U1)
Pole to anode open when, drive the triode (Q1)；The triode (Q1) string is used in the primary circuit of the isolation element
In being opened or closed the isolation element；The resistance of the reference resistance of each temperature detecting unit is different.
The isolation element is optic coupling element (U3), switching tube (Q3) corresponding to the secondary drive connection of optic coupling element.
The primary circuit of the optic coupling element and a branch circuit parallel connection, the reference resistance is in series with the branch road.
The branch road is to include a diode (D1), a current-limiting resistance (R11) and the reference resistance (R10), limit
Leakage resistance (R11) connects the thermistor (R1) and the series connection point of reference resistance (R10).
The precision voltage regulator is TL432 or TL431.
The circuit of the present invention, is divided into two-stage or multi-step temperature threshold value, each temperature detecting unit (every grade of temperature in other words
Detection unit) different temperature thresholds is corresponded to, by making each temperature detecting unit drive the conducting of a partial pressure branch road to obtain
Realize；When the temperature detecting unit of certain one-level acts because temperature exceedes own temperature threshold value, corresponding partial pressure branch will be turned on
Road, so as to drag down output voltage, the output voltage for making late-class circuit is reduced and arrives corresponding degree.Such as first order temperature detection
Unit acts, and its corresponding partial pressure branch road conducting ground connection, reduces output voltage, when second level temperature detecting unit acts, its
Corresponding partial pressure branch road is also switched on being grounded, and output is further reduced.Can set makes the precision voltage regulator of afterbody dynamic
When making, output is reduced zero, that is, realizes and shut down.
Brief description of the drawings
Fig. 1 is the thermal-shutdown circuit of prior art；
Fig. 2 is a kind of thermal-shutdown circuit of the embodiment of the present invention.
Embodiment
The present invention will be further described in detail below in conjunction with the accompanying drawings.
A kind of thermal-shutdown circuit as shown in Figure 2, including two temperature detecting units, and a protection circuit, should
Protection circuit is by the voltage source VCC2, the divider resistance R4 that are sequentially connected in series, two partial pressure branch roads compositions in parallel；First
Individual partial pressure branch road is grounded for the Q3 and R8, R8 of series connection, and second partial pressure branch road is Q4, and Q4 is directly grounded.TEMP_CTRL is partial pressure
The series connection point of branch road and divider resistance R4, it is the output end of protection circuit.
Two temperature detecting units, first temperature detecting unit, it is the temperature sensing circuit formed by precision voltage regulator,
The temperature sensing circuit includes reference power supply VCC1 and U3, U3 use TL432 (can also use TL431), and U3 reference edge connects
Thermistor R1 and reference resistance R10 series connection point are connect, U3 output driving connecting triode Q1 connects Q1 base stages, Q1 is penetrated
Pole connects VCC1, colelctor electrode connection optic coupling element U3 secondary circuit.The secondary drive connection Q3 of optic coupling element, that is, connect Q3 bases
Pole.
Second temperature detecting unit, identical with first temperature detecting unit structure, its corresponding optocoupler U4 secondary drives
Dynamic connection Q4.
Circuit operation principle is as follows：
With the rise of temperature, R1 and R2 resistance decrease, U1, U2 reference edge partial pressure rise, and setting R10 resistances are more than
R9, therefore U1 benchmark terminal voltage first reaches 2.495V (TL432 reference voltage), U1 negative electrode is open-minded to anode, Q1 base stage
Voltage is less than colelctor electrode, therefore Q1 C-E is turned on, and VCC1 flows to D1, R11 branch road and U3, R6 branch road by Q1.Q1, D1, R11 with
Connected after R1 parallel connections with R10 (it is also assumed that U3 primary side+R6 is in parallel with D1+R11+R10), it is voltage liter to make U1 reference edges
Height, a hysteresis circuit is formed, can prevent from shaking.After optocoupler U3 primary side is opened, VCC2 is by its secondary by NPN triode
Q3 is open-minded, and the R8 and R4 of first partial pressure branch road form branch pressure voltage, the voltage at TEMP_CTRL ends is changed into VCC2/2 from VCC2
(R8 is identical with R4 resistances here).When temperature continues to raise, and U2 benchmark terminal voltage is reached 2.495V, similarly, Q4 C-E
Conducting, the resistance of second partial pressure branch road is zero, so TEMP_CTRL voltages are 0.
TEMP_CTRL signals are sent to main control unit and handled, so as to control power model output par, c power or
Person shuts down.That is, in the present embodiment, there is provided two temperature thresholds, and when temperature is less than two threshold values, output is high
Level, when temperature reaches threshold value 1, intermediate level is exported, when temperature reaches threshold value 2, export low level.The level letter of output
Number main control unit is sent to, the basis for estimation as main control unit:High level is that temperature is normal, the normal work of power model
Make；Intermediate level is overheats, power model output par, c power；Low level is overheat protector, closes power model.
In above example, R8 is identical with R4 resistances, as other embodiment, can also unrestricted choice R8 and R4 pass
System, it is setting value to make TEMP_CTRL output voltages.
The temperature detecting unit of three or more than three can also be set, and each temperature detecting unit corresponds to different temperature
Threshold value (i.e. settable by reference resistance R10, R9 resistance difference), the partial pressure branch road of driving three or more than three.With
Temperature raises, and during more partial pressure branch circuit parallel connections, parallel resistance is smaller, TEMP_CTRL output voltages is further reduced.
As other embodiment, optic coupling element U3, U4 can also use other isolation elements, such as transformer.
As other embodiment, temperature detecting unit can also use other analog circuits, such as temperature-sensitive element+amplifier
The temperature detecting unit of formation, it is desirable to can in specified temp output drive signal.
Embodiment of the present invention is presented above, but the present invention is not limited to described embodiment.
Under the thinking that provides of the present invention, using by the way of being readily apparent that to those skilled in the art to the skill in above-described embodiment
Art means enter line translation, replacement, modification, and play a part of with the present invention in relevant art means it is essentially identical, realize
Goal of the invention it is also essentially identical, the technical scheme so formed is finely adjusted to be formed to above-described embodiment, this technology
Scheme is still fallen within protection scope of the present invention.
Claims (6)
- A kind of 1. thermal-shutdown circuit, it is characterised in that including at least two temperature detecting units, and the electricity of the output by connecting The protection electricity that potential source (VCC2), a divider resistance (R4) and partial pressure branch road in parallel with temperature detecting unit same number are formed Road, is equipped with a switching tube on each partial pressure branch road, and the tie point of the divider resistance and each partial pressure branch road is used to connect electricity Press output end；Each temperature detecting unit corresponds to the switching tube described in drive connection one by isolation element；Each temperature Temperature threshold difference corresponding to detection unit is spent, the resistance of partial pressure branch road corresponding to each temperature detecting unit is different.
- 2. a kind of thermal-shutdown circuit according to claim 1, it is characterised in that the temperature detecting unit is by precision The temperature sensing circuit that source of stable pressure is formed, the temperature sensing circuit include reference power supply (VCC1) and precision voltage regulator (U1), essence The series connection point of the reference edge connection thermistor (R1) and reference resistance (R10) of close source of stable pressure (U1), precision voltage regulator (U1) Output driving connecting triode (Q1), for when the negative electrode of precision voltage regulator (U1) is opened to anode, driving the triode (Q1)；The triode (Q1) string is in the primary circuit of the isolation element, for being opened or closed the isolation element；Respectively The resistance of the reference resistance of temperature detecting unit is different.
- 3. a kind of thermal-shutdown circuit according to claim 2, it is characterised in that the isolation element is optic coupling element (U3), switching tube (Q3) corresponding to the secondary drive connection of optic coupling element.
- A kind of 4. thermal-shutdown circuit according to claim 3, it is characterised in that the primary circuit of the optic coupling element with One branch circuit parallel connection, the reference resistance is in series with the branch road.
- 5. a kind of thermal-shutdown circuit according to claim 4, it is characterised in that the branch road is to include a diode (D1), a current-limiting resistance (R11) and the reference resistance (R10), current-limiting resistance (R11) connect the thermistor (R1) with The series connection point of reference resistance (R10).
- A kind of 6. thermal-shutdown circuit according to claim 2, it is characterised in that the precision voltage regulator be TL432 or TL431。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510849472.9A CN105490247B (en) | 2015-11-27 | 2015-11-27 | A kind of thermal-shutdown circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510849472.9A CN105490247B (en) | 2015-11-27 | 2015-11-27 | A kind of thermal-shutdown circuit |
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| Publication Number | Publication Date |
|---|---|
| CN105490247A CN105490247A (en) | 2016-04-13 |
| CN105490247B true CN105490247B (en) | 2018-01-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510849472.9A Active CN105490247B (en) | 2015-11-27 | 2015-11-27 | A kind of thermal-shutdown circuit |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109387296B (en) * | 2018-10-29 | 2021-05-18 | 许继集团有限公司 | Temperature detection circuit |
| CN117782340B (en) * | 2024-02-26 | 2024-05-03 | 深圳安森德半导体有限公司 | Over-temperature detection circuit |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101707350A (en) * | 2009-10-21 | 2010-05-12 | 海洋王照明科技股份有限公司 | Overheat protection circuit and switch power supply circuit |
| CN104184117A (en) * | 2013-05-27 | 2014-12-03 | 深圳市海洋王照明工程有限公司 | Over-temperature protection device and electronic equipment |
| CN204144923U (en) * | 2014-09-01 | 2015-02-04 | 江苏方程电力科技有限公司 | A kind of high-power IGBT temperature sampling protective circuit |
-
2015
- 2015-11-27 CN CN201510849472.9A patent/CN105490247B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101707350A (en) * | 2009-10-21 | 2010-05-12 | 海洋王照明科技股份有限公司 | Overheat protection circuit and switch power supply circuit |
| CN104184117A (en) * | 2013-05-27 | 2014-12-03 | 深圳市海洋王照明工程有限公司 | Over-temperature protection device and electronic equipment |
| CN204144923U (en) * | 2014-09-01 | 2015-02-04 | 江苏方程电力科技有限公司 | A kind of high-power IGBT temperature sampling protective circuit |
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| CN105490247A (en) | 2016-04-13 |
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