CN204214569U - Based on the temperature sensing circuit of transformer isolation - Google Patents
Based on the temperature sensing circuit of transformer isolation Download PDFInfo
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- CN204214569U CN204214569U CN201420625391.1U CN201420625391U CN204214569U CN 204214569 U CN204214569 U CN 204214569U CN 201420625391 U CN201420625391 U CN 201420625391U CN 204214569 U CN204214569 U CN 204214569U
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- resistance
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Abstract
The utility model relates to a kind of temperature sensing circuit based on transformer isolation, its technical characterstic is: comprise control chip, current-limiting resistance R1, capacitance C1, isolation sampling unit and voltage signal generation unit, described control chip output switch parameter mouth connects current-limiting resistance R1, after this resistance R1 connects with capacitance C1, receive respectively on isolation sampling unit and voltage signal generation unit, the output signal of voltage signal generation unit is connected to the analog input port of control chip.Thermistor and control circuit can be isolated by transformer by the utility model, and achieve needing the object temperature of electrical isolation to measure, improve the safety and reliability of measurement, circuit structure is simple.
Description
Technical field
The utility model belongs to temperature detection technical field, especially a kind of temperature sensing circuit based on transformer isolation.
Background technology
Thermistor is a kind of thermally sensitive electronic component, shows different resistance values at different temperatures.Different according to temperature coefficient, thermistor is divided into posistor (PTC) and negative tempperature coefficient thermistor (NTC) two class, and the former resistance value when temperature is higher is larger, and the latter's resistance value when temperature is higher is less.The temperature of thermistor i.e. testee can be determined by the resistance value of Measurement accuracy thermistor.
At present, adopt the basic circuit of thermistor detected temperatures as shown in Figure 1, this temperature sensing circuit adopts a reference voltage source U1 to power, by resistance R1 and the thermistor RT dividing potential drop of a known resistance, then by the voltage U 2 on analog input Port detecting thermistor, formula is: U2=U1*RT/ (R1+RT), testee temperature is calculated finally by respective algorithms, or the resistance value of RT is derived by the voltage U 2 recorded, then being tabled look-up by the corresponding relation of RT resistance value and temperature draws the temperature of testee.Above-mentioned detection method is simple, accurate, but this temperature sensing circuit does not consider the isolating problem measured when needing the object temperature of electrical isolation.
Summary of the invention
The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of temperature sensing circuit based on transformer isolation, solves the isolating problem measured when needing the object temperature of electrical isolation.
The utility model solves existing technical matters and takes to be achieved through the following technical solutions:
A kind of temperature sensing circuit based on transformer isolation, comprise control chip, current-limiting resistance R1, capacitance C1, isolation sampling unit and voltage signal generation unit, the output switch parameter mouth of described control chip connects current-limiting resistance R1, after resistance R1 connects with capacitance C1, receive respectively on isolation sampling unit and voltage signal generation unit, the output signal of this voltage signal generation unit is connected to the analog input port of control chip.
And, described isolation sampling unit comprises transformer and thermistor RT, one end of transformer primary side is connected on the common point of capacitance C1 and voltage signal generation unit, the other end of transformer primary side is connected on the power supply ground of control chip, and the two ends of transformer secondary are connected with thermistor RT respectively.
And, described voltage signal generation unit comprises diode D2, electric capacity C2, sustained diode 1 and resistance R2, described diode D2, electric capacity C2 and diode D1 connect successively, resistance R2 is connected in parallel on electric capacity C2, the common point of diode D1, electric capacity C2 and resistance R2 is connected on the power supply of control chip on the ground, and the common point of diode D2, electric capacity C2 and resistance R2 receives the analog input port of control chip as output signal.
And described control chip is the integrating control chip with at least one output switch parameter port and at least one analog input port.
Advantage of the present utility model and good effect are:
1, thermistor and control circuit are isolated by transformer by this temperature sensing circuit, achieve the temperature measurement function to the object needing electrical isolation, improve the safety and reliability of measurement.
2, this temperature sensing circuit sends the square-wave signal of certain frequency and dutycycle by the output switch parameter mouth of control chip, does not need additionally to provide power supply; Meanwhile, utilize the analog input port of control chip to detect magnitude of voltage in real time, by tabling look-up or calculating the real time temperature of testee, circuit structure is simple.
Accompanying drawing explanation
Fig. 1 is the basic circuit diagram of existing employing thermistor detected temperatures;
Fig. 2 is circuit theory diagrams of the present utility model;
In figure, 1-isolates sampling unit, 2-voltage signal generation unit.
Embodiment
Below in conjunction with accompanying drawing, the utility model embodiment is further described.
A kind of temperature sensing circuit based on transformer isolation, as shown in Figure 2, comprise control chip, resistance R1, electric capacity C1, isolation sampling unit 1 and voltage signal generation unit 2, described control chip is the integrating control chip with at least one output switch parameter port and at least one analog input port, the output switch parameter mouth of this control chip sends frequency and the certain square-wave signal of dutycycle, after the series circuit of resistance R1 and electric capacity C1, be connected respectively to isolation sampling unit and voltage signal generation unit, the output signal of this voltage signal generation unit is connected to the analog input port of control chip, control chip is by tabling look-up or calculating the real time temperature of testee.
The physical circuit of isolation sampling unit is: comprise transformer and thermistor RT, one end of described transformer primary side is connected on the common point of electric capacity C1 and voltage signal generation unit, the other end of transformer primary side is connected on the power supply ground of control chip, and the two ends of transformer secondary are connected with the two ends of thermistor RT respectively; Thermistor RT resistance variation with temperature and changing, the voltage at transformer primary side two ends also can change thereupon.
The physical circuit of voltage signal generation unit is: comprise diode D2, electric capacity C2, diode D1 and resistance R2, described diode D2, electric capacity C2 and diode D1 connects successively, this resistance R2 is connected in parallel on electric capacity C2, last diode D1, the common point of electric capacity C2 and resistance R2 is connected on the power supply of control chip on the ground, diode D2, the common point of electric capacity C2 and resistance R2 receives the analog input port of control chip as output signal, control chip detects magnitude of voltage in real time by analog input port, by tabling look-up or calculating the real time temperature of testee.
It is emphasized that; embodiment described in the utility model is illustrative; instead of it is determinate; therefore the utility model comprises the embodiment be not limited to described in embodiment; every other embodiments drawn according to the technical solution of the utility model by those skilled in the art, belong to the scope of the utility model protection equally.
Claims (4)
1. the temperature sensing circuit based on transformer isolation, it is characterized in that: comprise control chip, current-limiting resistance R1, capacitance C1, isolation sampling unit and voltage signal generation unit, the output switch parameter mouth of described control chip connects current-limiting resistance R1, after resistance R1 connects with capacitance C1, receive respectively on isolation sampling unit and voltage signal generation unit, the output signal of this voltage signal generation unit is connected to the analog input port of control chip.
2. the temperature sensing circuit road based on transformer isolation according to claim 1, it is characterized in that: described isolation sampling unit comprises transformer and thermistor RT, one end of transformer primary side is connected on the common point of capacitance C1 and voltage signal generation unit, the other end of transformer primary side is connected on the power supply ground of control chip, and the two ends of transformer secondary are connected with thermistor RT respectively.
3. the temperature sensing circuit road based on transformer isolation according to claim 1, it is characterized in that: described voltage signal generation unit comprises diode D2, electric capacity C2, sustained diode 1 and resistance R2, described diode D2, electric capacity C2 and diode D1 connect successively, resistance R2 is connected in parallel on electric capacity C2, the common point of diode D1, electric capacity C2 and resistance R2 is connected on the power supply of control chip on the ground, and the common point of diode D2, electric capacity C2 and resistance R2 receives the analog input port of control chip as output signal.
4. the temperature sensing circuit road based on transformer isolation according to any one of claims 1 to 3, is characterized in that: described control chip is the integrating control chip with at least one output switch parameter port and at least one analog input port.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420625391.1U CN204214569U (en) | 2014-10-27 | 2014-10-27 | Based on the temperature sensing circuit of transformer isolation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420625391.1U CN204214569U (en) | 2014-10-27 | 2014-10-27 | Based on the temperature sensing circuit of transformer isolation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204214569U true CN204214569U (en) | 2015-03-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420625391.1U Expired - Fee Related CN204214569U (en) | 2014-10-27 | 2014-10-27 | Based on the temperature sensing circuit of transformer isolation |
Country Status (1)
| Country | Link |
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| CN (1) | CN204214569U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104330186A (en) * | 2014-10-27 | 2015-02-04 | 天津电气科学研究院有限公司 | Temperature detection circuit based on transformer isolation |
| CN105786048A (en) * | 2016-03-25 | 2016-07-20 | 广州美易来智能电器有限公司 | Device and method for controlling cooling temperature rapidly accurately |
-
2014
- 2014-10-27 CN CN201420625391.1U patent/CN204214569U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104330186A (en) * | 2014-10-27 | 2015-02-04 | 天津电气科学研究院有限公司 | Temperature detection circuit based on transformer isolation |
| CN104330186B (en) * | 2014-10-27 | 2017-02-15 | 天津电气科学研究院有限公司 | Temperature detection circuit based on transformer isolation |
| CN105786048A (en) * | 2016-03-25 | 2016-07-20 | 广州美易来智能电器有限公司 | Device and method for controlling cooling temperature rapidly accurately |
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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 | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150318 Termination date: 20171027 |