CN203660874U - Overheat protection circuit - Google Patents
Overheat protection circuit Download PDFInfo
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- CN203660874U CN203660874U CN201320664621.0U CN201320664621U CN203660874U CN 203660874 U CN203660874 U CN 203660874U CN 201320664621 U CN201320664621 U CN 201320664621U CN 203660874 U CN203660874 U CN 203660874U
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- divider resistance
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Abstract
An embodiment of the utility model discloses an overheat protection circuit comprising a temperature detection circuit, a comparison circuit and a control circuit, wherein the temperature detection circuit is used for obtaining temperature information voltage according to a surrounding environment temperature, the comparison circuit is connected with the temperature detection circuit and is used for comparing the temperature information voltage obtained through the temperature detection circuit with preset reference voltage, and a first comparison result is acquired. The control circuit is respectively connected with the comparison circuit and a power supply output end and is used for controlling an output current of the power supply output end according to a first comparison result obtained through the comparison circuit. By adopting the overheat protection circuit, when an electronic product is high in temperature, power consumption can be reduced and therefore the electronic product can be lowered in temperature through reduction of a power supply current of the electronic product, and overheat protection effects are realized. The overheat protection circuit is characterized by strong reusability, small quantity of electronic components and low cost.
Description
Technical field
The present invention relates to electronic technology field, relate in particular to a kind of overheating protection circuit.
Background technology
Along with the development of electronic technology, electronic product miscellaneous arises at the historic moment, also different to the requirement of its electric power system according to its different purposes.The desired electric power systems of electronic product such as such as LED illuminator, LED backlit display and LED-backlit TV are constant-current supply system, while use under environment after long work or out of doors, can produce serious heating.High temperature, high heat will make this electronic product produce the consequences such as colour cast, light efficiency reduction and life-span minimizing.
Now current solution is, in use procedure, in the time of this series products excessive heating, closes its power supply, stops its consumption heating.But this will cause product temporarily cannot use, user is experienced and causes bad impact.
Utility model content
The utility model embodiment technical problem to be solved is; a kind of overheating protection circuit is provided; at electronic product during in high temperature; by reducing its supply current; realize the function that reduces power consumption and reduce electronic product temperature; play the effect of overtemperature protection, there is the feature that durability is strong, electronic devices and components are few and cost is low simultaneously.
In order to solve the problems of the technologies described above, the utility model embodiment provides a kind of overheating protection circuit, comprises temperature sensing circuit, comparison circuit and control circuit, wherein:
Described temperature sensing circuit is for obtaining temperature information voltage according to ambient temperature;
Described comparison circuit is connected with described temperature sensing circuit, compares, and obtain the first comparative result for temperature information voltage and preset reference voltage that described temperature sensing circuit is got;
Described control circuit is connected with power supply output with described comparison circuit respectively, for the first comparative result getting according to described comparison circuit, controls the output current of power supply output.
Implement the utility model embodiment; there is following beneficial effect: temperature information voltage and preset reference voltage that the utility model embodiment gets according to temperature sensing circuit by comparison circuit compare; if temperature information voltage is higher; output control module will reduce supply current; realize the function that reduces power consumption and reduce electronic product temperature; play the effect of overtemperature protection, there is the feature that durability is strong, electronic devices and components are few and cost is low simultaneously.
Brief description of the drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is the structural representation of a kind of overheating protection circuit of providing of the utility model embodiment;
Fig. 2 is the circuit theory diagrams of a kind of overheating protection circuit application that provides of the utility model embodiment;
Fig. 3 is the circuit theory diagrams of the another kind of overheating protection circuit application that provides of the utility model embodiment.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtaining under creative work prerequisite, all belong to the scope of the utility model protection.
What the utility model embodiment provided supplies electrical input; be applied to electronic product power source end; can power to electronic product, a kind of overheating protection circuit that the utility model embodiment provides can be controlled the output current of power supply input, thereby reaches the effect of overtemperature protection.
Fig. 1 is the structural representation of a kind of overheating protection circuit in the utility model embodiment.Overheating protection circuit in the utility model embodiment at least can comprise temperature sensing circuit 110, comparison circuit 120, control circuit 130 as shown in the figure, wherein:
Temperature sensing circuit 110, for obtaining temperature information voltage according to ambient temperature.
Concrete, temperature sensing circuit comprises thermistor and the 3rd divider resistance, after thermistor and the series connection of the 3rd divider resistance, at the default pressure drop voltage of two ends access, thermistor is connected with comparison circuit with one end of the 3rd divider resistance series connection.
Further, overheating protection circuit also comprises reference voltage source, reference voltage source anodal and publicly between pressure drop voltage be default pressure drop voltage, in addition, thermistor comprises semistor and negative tempperature coefficient thermistor, wherein:
If thermistor is semistor, one end of semistor is connected with comparison circuit with one end of the 3rd divider resistance simultaneously, the other end of semistor connects publicly, and the other end of the 3rd divider resistance connects the positive pole of reference voltage source;
If thermistor is negative tempperature coefficient thermistor, one end of negative tempperature coefficient thermistor is connected with comparison circuit with one end of the 3rd divider resistance simultaneously, the other end of negative tempperature coefficient thermistor connects the positive pole of reference voltage source, and the other end of the 3rd divider resistance connects publicly.
Concrete, comparison circuit comprises voltage comparator, and the reference input of voltage comparator accesses described preset reference voltage, and the second input of voltage comparator is connected with temperature sensing circuit.
Further, comparison circuit also wraps the first divider resistance and the second divider resistance, wherein, the reference input of described voltage comparator is connected with one end of the second divider resistance with the first divider resistance simultaneously, the other end of the first divider resistance be connected publicly, the other end of the second divider resistance and reference voltage source are anodal to be connected.The voltage that it is pointed out that the first divider resistance and the second divider resistance connecting place is preset reference voltage.
Concrete, control circuit comprises photoelectrical coupler and switch chip, wherein, the transmitting terminal of photoelectrical coupler is connected with comparison circuit, the receiving terminal of photoelectrical coupler is connected with the input of switch chip, the output of switch chip is connected with power supply output, for controlling the output current of described power supply output.
Refer to Fig. 1, the overheating protection circuit in the utility model embodiment can also comprise current detection circuit 140 as shown in the figure, and current detection circuit 140 is for obtaining feedback voltage according to the output current of power supply output.
Especially, comparison circuit 120 is connected with current detection circuit 140, feedback voltage and the preset reference voltage that current detection circuit 140 can be got compare, and obtain the second comparative result, the second comparative result that control circuit 130 can get according to comparison circuit 120, the output current of control power supply output.
Concrete, current detection circuit comprises current sampling resistor, and one end of current sampling resistor is connected with power supply output, and the other end of current sampling resistor is connected with voltage comparator circuit.
For specific implementation process of the present utility model, will, by following circuit theory, at length set forth:
Fig. 2 is the circuit theory diagrams of a kind of overheating protection circuit application that provides of the utility model embodiment, wherein, circuit outside black surround is the circuit diagram of a kind of power supply unit in prior art, circuit in black surround is a kind of overheating protection circuit that the utility model provides, power supply output is V-, semistor is R31, the first divider resistance is R32, the second divider resistance is R2, the 3rd divider resistance is R29, voltage comparator is U2B, the reference input of voltage comparator is 5 pin of U2B, 6 pin that the second input of voltage comparator is U2B, the output of voltage comparator is 7 pin of U2B, photoelectrical coupler is U3, switch chip is U1, current sampling resistor is R25, reference voltage source is U4.It is pointed out that diode D4, diode D8 and capacitor C 18 are auxiliary element.
Concrete, temperature overheating protection process is as follows:
Because the semistor R31 in temperature sensing circuit 110 and the 3rd divider resistance R29 are connected on publicly between reference voltage source U4, therefore two ends keep constant voltage, for default pressure drop voltage, can default pressure drop voltage be set by changing the parameter of reference voltage source U4.In the time that the ambient temperature of electronic product raises, semistor R31 resistance increases gradually, it is large that thereby the dividing potential drop at semistor R31 two ends becomes, it is large that the voltage of Ua becomes, if when voltage increases to certain value, diode D4 forward conduction, the voltage of Ua is added to 6 pin of the voltage comparator U2B in comparison circuit 120 by diode D4.
In comparison circuit 120, the first divider resistance R32 and the second divider resistance R2 are connected on publicly between reference voltage source U4, therefore it is constant that the voltage of two resistance joints keeps, for preset reference voltage, 5 pin of access U2B, can arrange reference voltage by the resistance that changes the first divider resistance R32 and the second divider resistance R2.In the time that the 6 pin voltages (being the voltage of above-mentioned Ua) of voltage comparator U2B are greater than 5 pin voltage, pin 7 output low levels of voltage comparator U2B, now diode D8 conducting, makes the interior light emitting diodes of the photoelectrical coupler U3 in control circuit 130 luminous.
After the lumination of light emitting diode of the photoelectrical coupler U3 inside in control circuit 130, the phototriode of photoelectrical coupler U3 inside will be according to the light signal receiving, change frequency or the duty ratio of the switch chip U1 in control circuit 130, thereby make switch chip U1 control power supply output V-(or V+) output current reduce.Output current reduces to make power output to reduce, and after power reduces, electronic product heating will reduce, thereby reaches temperature overheating protection and be not related to the object of the end electronic product of having no progeny.
Concrete, constant current control procedure is as follows:
In the time that the electric current in power supply output V-increases, the voltage on the current sampling resistor R25 in current detection circuit 140 also can increase, and this voltage is added to 6 pin of the voltage comparator U2B in comparison circuit 120 by circuit.
In the time that the 6 pin voltages of the voltage comparator U2B in comparison circuit 120 are greater than 5 pin voltage, pin 7 output low levels of voltage comparator U2B, now diode D8 conducting, makes the interior light emitting diodes of the photoelectrical coupler U3 in control circuit 130 luminous.
After the lumination of light emitting diode of the photoelectrical coupler U3 inside in control circuit 130, the phototriode of photoelectrical coupler U3 inside will be according to the light signal receiving, change frequency or the duty ratio of the switch chip U1 in control circuit 130, thereby make switch chip U1 control power supply output V-(or V+) output current reduce, reach constant current output, thereby avoid the output of high electric current and make the object of rear end electronic product heating.
Fig. 3 is the circuit theory diagrams of the another kind of overheating protection circuit application that provides of the utility model embodiment; be with Fig. 2 difference; the thermistor using is negative tempperature coefficient thermistor, and the connection of negative tempperature coefficient thermistor R31 and the 3rd divider resistance R29 as shown in Figure 3.
Concrete, in the time that the ambient temperature of electronic product raises, negative tempperature coefficient thermistor R31 resistance reduces gradually, thus the dividing potential drop at negative tempperature coefficient thermistor R31 two ends diminishes, and it is large that the voltage of Ua becomes.Other operation principle is identical with above-mentioned principle, repeats no more here.
Temperature information voltage and preset reference voltage that the utility model embodiment gets according to temperature sensing circuit by comparison circuit compare; if temperature information voltage is higher; output control module will reduce supply current; realize the function that reduces power consumption and reduce electronic product temperature; play the effect of overtemperature protection, there is the feature that durability is strong, electronic devices and components are few and cost is low simultaneously.
Above disclosed is only the utility model preferred embodiment, certainly can not limit with this interest field of the utility model, and the equivalent variations of therefore doing according to the utility model claim, still belongs to the scope that the utility model is contained.
Claims (6)
1. an overheating protection circuit; it is characterized in that; described overheating protection circuit comprises temperature sensing circuit, comparison circuit and control circuit; described comparison circuit gets described temperature sensing circuit temperature information voltage and preset reference voltage according to ambient temperature compare; and obtain the first comparative result; described control circuit is according to the output current of described the first comparative result control power supply output, wherein:
Described comparison circuit comprises voltage comparator, and the reference input of described voltage comparator accesses described preset reference voltage, and the second input of described voltage comparator is connected with described temperature sensing circuit;
Described control circuit comprises photoelectrical coupler and switch chip, wherein, the transmitting terminal of described photoelectrical coupler is connected with the output of described voltage comparator, the receiving terminal of described photoelectrical coupler is connected with the input of described switch chip, the output of described switch chip is connected with power supply output, and described switch chip is for controlling the output current of described power supply output.
2. overheating protection circuit as claimed in claim 1; it is characterized in that; described temperature sensing circuit comprises thermistor and the 3rd divider resistance; after described thermistor and described the 3rd divider resistance series connection, at the default pressure drop voltage of two ends access, described thermistor is connected with described comparison circuit with one end of described the 3rd divider resistance series connection.
3. overheating protection circuit as claimed in claim 1, is characterized in that, described overheating protection circuit also comprises current detection circuit, and described current detection circuit is for obtaining feedback voltage according to the output current of described power supply output;
Described comparison circuit is connected with described current detection circuit, compares, and obtain the second comparative result for feedback voltage and described preset reference voltage that described current detection circuit is got;
Described control circuit is connected with described power supply output with described comparison circuit respectively, for the second comparative result getting according to described comparison circuit, controls the output current of described power supply output.
4. overheating protection circuit as claimed in claim 3; it is characterized in that; described current detection circuit comprises current sampling resistor, and one end of described current sampling resistor is connected with described power supply output, and the other end of described current sampling resistor is connected with described voltage comparator circuit.
5. overheating protection circuit as claimed in claim 2, is characterized in that, described overheating protection circuit also comprises reference voltage source, described reference voltage source anodal and publicly between pressure drop voltage be described default pressure drop voltage;
Described thermistor comprises semistor and negative tempperature coefficient thermistor, wherein:
If described thermistor is semistor, one end of described semistor is connected with described comparison circuit with one end of described the 3rd divider resistance simultaneously, described in the other end of described semistor connects, publicly, the other end of described the 3rd divider resistance connects the positive pole of described reference voltage source;
If described thermistor is negative tempperature coefficient thermistor, one end of described negative tempperature coefficient thermistor is connected with described comparison circuit with one end of described the 3rd divider resistance simultaneously, the other end of described negative tempperature coefficient thermistor connects the positive pole of described reference voltage source, described in the other end of described the 3rd divider resistance connects publicly.
6. overheating protection circuit as claimed in claim 1, is characterized in that, described overheating protection circuit also comprises reference voltage source;
Described comparison circuit also wraps the first divider resistance and the second divider resistance, wherein, the reference input of described voltage comparator is connected with one end of described the second divider resistance with described the first divider resistance simultaneously, the other end of described the first divider resistance be connected publicly, the other end of described the second divider resistance is connected with described reference voltage source is anodal;
The voltage of described the first divider resistance and described the second divider resistance connecting place is described preset reference voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320664621.0U CN203660874U (en) | 2013-10-25 | 2013-10-25 | Overheat protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320664621.0U CN203660874U (en) | 2013-10-25 | 2013-10-25 | Overheat protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203660874U true CN203660874U (en) | 2014-06-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320664621.0U Expired - Fee Related CN203660874U (en) | 2013-10-25 | 2013-10-25 | Overheat protection circuit |
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| Country | Link |
|---|---|
| CN (1) | CN203660874U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109377956A (en) * | 2018-12-03 | 2019-02-22 | 惠科股份有限公司 | Protect circuit and power supply circuit |
| CN112859965A (en) * | 2021-01-18 | 2021-05-28 | 深圳市道通智能航空技术股份有限公司 | Temperature control circuit and electronic equipment |
-
2013
- 2013-10-25 CN CN201320664621.0U patent/CN203660874U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109377956A (en) * | 2018-12-03 | 2019-02-22 | 惠科股份有限公司 | Protect circuit and power supply circuit |
| US11222610B2 (en) | 2018-12-03 | 2022-01-11 | HKC Corporation Limited | Protection circuit, power supply circuit, and display panel |
| CN112859965A (en) * | 2021-01-18 | 2021-05-28 | 深圳市道通智能航空技术股份有限公司 | Temperature control circuit and electronic equipment |
| CN112859965B (en) * | 2021-01-18 | 2022-08-26 | 深圳市道通智能航空技术股份有限公司 | Temperature control circuit and electronic equipment |
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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 |
Granted publication date: 20140618 Termination date: 20151025 |
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| EXPY | Termination of patent right or utility model |