CN203719790U - NTC identification circuit with high return difference - Google Patents
NTC identification circuit with high return difference Download PDFInfo
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- CN203719790U CN203719790U CN201320807101.0U CN201320807101U CN203719790U CN 203719790 U CN203719790 U CN 203719790U CN 201320807101 U CN201320807101 U CN 201320807101U CN 203719790 U CN203719790 U CN 203719790U
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- resistance
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- electronic switch
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Abstract
The utility model provides an NTC identification circuit with high return difference. A positive input end of a comparator is respectively connected with one end of a temperature sensor with negative temperature coefficients and one end of a first resistor. The other end of the first resistor is connected with one end of a second resistor. The other end of the second resistor is connected with the negative input end of the comparator. One end of the second resistor is connected with a reference voltage. The positive input end of the comparator is respectively connected with one end of a ninth resistor and one end of a tenth resistor. The other end of the tenth resistor is connected with a drain electrode of a second electronic switch. The grid electrode of the electronic switch is respectively connected with one end of an eleventh resistor and one end of a twelfth resistor. The other end of the eleventh resistor and the source electrode of the electronic switch are connected with the ground. The other end of the twelfth resistor is connected with a negative electrode of an optical coupler. The positive electrode of the optical coupler is respectively connected with one end of a working voltage and one end of a third resistor. The NTC identification circuit is reliable, cheap and convenient to adjust, has a wide system return difference range, and can ensure safety of a low-voltage control circuit.
Description
Technical field
The utility model relates to electronic technology field, particularly a kind of high return difference NTC identification circuit.
Background technology
NTC(thermistor) protection for power device especially high-power IGBT (insulated gate bipolar transistor) is thing in recent years; it is compared with traditional mechanical temperature-control; there is reaction velocity fast; and the advantages such as temperature survey precision; but the data-switching of the NTC of continuous temperature measurement to be become can be used for the input parameter of control system protection; must be through bridge type comparison, amplification, then by the method for analog or digital, processing could be for system monitoring.
The shortcoming of existing technology is that signal processing cost is high, and is easily interfered in high power welding power supply, and cost is relatively high; Mimic channel is realized complicated, and regulates inconvenience, and especially realizing high return difference does not have ready-made available solutions, and implemented in digital is expensive, is easily interfered again.
Summary of the invention
The utility model provides a kind of high return difference NTC identification circuit, and it is reliable, cheap, easy to adjust, and can guarantee the safety of low-voltage control circuit.
To achieve these goals, the utility model provides following technical scheme:
A kind of high return difference NTC identification circuit, it comprises: comparer U1 and optocoupler U2, the electrode input end of described comparer U1 connects respectively one end of temperature sensor RT1 and one end of the first resistance R 1 of negative temperature coefficient, the other end ground connection of described temperature sensor RT1, the other end of described the first resistance R 1 connects one end of the second resistance R 2, the other end of described the second resistance R 2 connects the negative input of comparer U1, and one end of described the second resistance R 2 also connects reference voltage Vref;
The electrode input end of described comparer U1 connects respectively one end of the 9th resistance R 9 and one end of the tenth resistance R 10, the other end ground connection of described the 9th resistance R 9, the other end of described the tenth resistance R 10 connects the drain electrode of the second electronic switch Q2, the grid of described electronic switch Q2 connects respectively the 11 one end of resistance R 11 and one end of the 12 resistance R 12, the source ground of the other end of described the 11 resistance R 11 and described electronic switch Q2, the other end of described the 12 resistance R 12 connects the negative pole of optocoupler U2;
The anode of described optocoupler U2 connects respectively one end of operating voltage Vc and the 3rd resistance R 3, and the other end of described the 3rd resistance R 3 connects respectively the signal output part of described comparer U1 and one end of the 9th resistance R 9;
The power end of described comparer U1 connects operating voltage Vc, the earth terminal ground connection of described comparer U1;
The negative pole of described optocoupler U2 also connects the drain electrode of the first electronic switch Q1, the source ground of described the first electronic switch Q1, the grid of described electronic switch Q1 connects one end of the 6th resistance R 6 and one end of the 7th resistance R 7, the other end of described the 6th resistance R 6 connects the signal output part of described comparer U1, the other end ground connection of described the 7th resistance R 7, described optocoupler U2 has signal output part OUT.
Preferably, between the anode of described optocoupler U2 and one end of the 3rd resistance R 3, be also serially connected with the 4th resistance R 4.
Preferably, between the other end of described the 3rd resistance R 3 and one end of the 9th resistance R 9, be serially connected with the 8th resistance R 8.
By implementing above technical scheme, there is following technique effect: the high return difference NTC identification circuit that the utility model provides, it is reliable, cheap, easy to adjust, system return difference wide ranges, realize switching value access control system simultaneously and isolate with testing circuit, guaranteeing the safety of low-voltage control circuit.
Accompanying drawing explanation
The high return difference NTC identification circuit schematic diagram that Fig. 1 provides for the utility model embodiment.
Embodiment
In order better to understand the technical solution of the utility model, below in conjunction with accompanying drawing, describe the embodiment that the utility model provides in detail.
The utility model embodiment provides a kind of high return difference NTC identification circuit, as shown in Figure 1, it comprises: comparer U1 and optocoupler U2, the electrode input end of described comparer U1 connects respectively one end of temperature sensor RT1 and one end of the first resistance R 1 of negative temperature coefficient, the other end ground connection of described temperature sensor RT1, the other end of described the first resistance R 1 connects one end of the second resistance R 2, the other end of described the second resistance R 2 connects the negative input of comparer U1, and one end of described the second resistance R 2 also connects reference voltage Vref;
The electrode input end of described comparer U1 connects respectively one end of the 9th resistance R 9 and one end of the tenth resistance R 10, the other end ground connection of described the 9th resistance R 9, the other end of described the tenth resistance R 10 connects the drain electrode of the second electronic switch Q2, the grid of described electronic switch Q2 connects respectively the 11 one end of resistance R 11 and one end of the 12 resistance R 12, the source ground of the other end of described the 11 resistance R 11 and described electronic switch Q2, the other end of described the 12 resistance R 12 connects the negative pole of optocoupler U2;
The anode of described optocoupler U2 connects respectively one end of operating voltage Vc and the 3rd resistance R 3, and the other end of described the 3rd resistance R 3 connects respectively the signal output part of described comparer U1 and one end of the 9th resistance R 9;
The power end of described comparer U1 connects operating voltage Vc, the earth terminal ground connection of described comparer U1;
The negative pole of described optocoupler U2 also connects the drain electrode of the first electronic switch Q1, the source ground of described the first electronic switch Q1, the grid of described electronic switch Q1 connects one end of the 6th resistance R 6 and one end of the 7th resistance R 7, the other end of described the 6th resistance R 6 connects the signal output part of described comparer U1, the other end ground connection of described the 7th resistance R 7, described optocoupler U2 has signal output part OUT.
In other embodiments, on above-described embodiment basis, further, between the anode of described optocoupler U2 and one end of the 3rd resistance R 3, be also serially connected with the 4th resistance R 4.
In other embodiments, on above-described embodiment basis, further, between the other end of described the 3rd resistance R 3 and one end of the 9th resistance R 9, be serially connected with the 8th resistance R 8.
The temperature sensor RT1 of negative temperature coefficient and the first resistance R 1 form the negative pole input circuit of comparer U1, the second resistance R 2, the 9th resistance R 9, the tenth resistance R 10 of being controlled by electronic switch Q2 forms the anodal input circuit of comparer U1, the 8th resistance R 8 is positive feedback, when temperature is lower, the current potential of the negative input of comparer U1 is higher than electrode input end current potential, the signal output part output electronegative potential of comparer U1, the first electronic switch Q1 cut-off, the second electronic switch Q2 opens, the 9th resistance R 9 and the tenth resistance R 10 parallel connections, positive electrode potential is lower, when the temperature sensor of respective temperature sensor RT1 must be higher, comparer U1 could overturn, once temperature reaches design temperature, comparer U1 upset changes noble potential into by electronegative potential, the first electronic switch Q1 conducting, optocoupler U2 activates and has its output terminal OUT send guard signal to control circuit and realize the electrical isolation of signal, the first electronic switch Q1 cut-off simultaneously, the positive pole of comparer U1 becomes by the second resistance R 2 and the 9th resistance R 9 dividing potential drops, and just electrode potential is corresponding raises, and respective temperature sensor must be returned to lower temperature and could overturn.With a simple circuit, be so the highly reliable large return difference protection action that has realized temperature sensing circuit; because once the specification of temperature sensor RT1 is determined; the calculating that just can pass through the first resistance R 1, the second resistance R 2, the 9th resistance R 9, the tenth resistance R 10 realizes operating temperature and the protection temperature of setting, and circuit is precisely reliable.
A kind of high return difference NTC identification circuit above the utility model embodiment being provided is described in detail, for one of ordinary skill in the art, thought according to the utility model embodiment, all will change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model.
Claims (3)
1. one kind high return difference NTC identification circuit, it is characterized in that, comprise: comparer U1 and optocoupler U2, the electrode input end of described comparer U1 connects respectively one end of temperature sensor RT1 and one end of the first resistance R 1 of negative temperature coefficient, the other end ground connection of described temperature sensor RT1, the other end of described the first resistance R 1 connects one end of the second resistance R 2, the other end of described the second resistance R 2 connects the negative input of comparer U1, and one end of described the second resistance R 2 also connects reference voltage Vref;
The electrode input end of described comparer U1 connects respectively one end of the 9th resistance R 9 and one end of the tenth resistance R 10, the other end ground connection of described the 9th resistance R 9, the other end of described the tenth resistance R 10 connects the drain electrode of the second electronic switch Q2, the grid of described electronic switch Q2 connects respectively the 11 one end of resistance R 11 and one end of the 12 resistance R 12, the source ground of the other end of described the 11 resistance R 11 and described electronic switch Q2, the other end of described the 12 resistance R 12 connects the negative pole of optocoupler U2;
The anode of described optocoupler U2 connects respectively one end of operating voltage Vc and the 3rd resistance R 3, and the other end of described the 3rd resistance R 3 connects respectively the signal output part of described comparer U1 and one end of the 9th resistance R 9;
The power end of described comparer U1 connects operating voltage Vc, the earth terminal ground connection of described comparer U1;
The negative pole of described optocoupler U2 also connects the drain electrode of the first electronic switch Q1, the source ground of described the first electronic switch Q1, the grid of described electronic switch Q1 connects one end of the 6th resistance R 6 and one end of the 7th resistance R 7, the other end of described the 6th resistance R 6 connects the signal output part of described comparer U1, the other end ground connection of described the 7th resistance R 7, described optocoupler U2 has signal output part OUT.
2. high return difference NTC identification circuit as claimed in claim 1, is characterized in that, between the anode of described optocoupler U2 and one end of the 3rd resistance R 3, is also serially connected with the 4th resistance R 4.
3. high return difference NTC identification circuit as claimed in claim 1, is characterized in that, between the other end of described the 3rd resistance R 3 and one end of the 9th resistance R 9, is serially connected with the 8th resistance R 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320807101.0U CN203719790U (en) | 2013-12-11 | 2013-12-11 | NTC identification circuit with high return difference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320807101.0U CN203719790U (en) | 2013-12-11 | 2013-12-11 | NTC identification circuit with high return difference |
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| Publication Number | Publication Date |
|---|---|
| CN203719790U true CN203719790U (en) | 2014-07-16 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320807101.0U Expired - Fee Related CN203719790U (en) | 2013-12-11 | 2013-12-11 | NTC identification circuit with high return difference |
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| Country | Link |
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| CN (1) | CN203719790U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104600660A (en) * | 2015-01-09 | 2015-05-06 | 广东瑞德智能科技股份有限公司 | Low-power-consumption short circuit protection circuit |
| CN107180527A (en) * | 2016-03-11 | 2017-09-19 | 包米勒公司 | Method and circuit arrangement for safe transmission of sensor signals |
| CN110044510A (en) * | 2019-05-17 | 2019-07-23 | 上海希形科技有限公司 | IGBT module temperature measurement circuit, temp measuring method and computer readable storage medium |
-
2013
- 2013-12-11 CN CN201320807101.0U patent/CN203719790U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104600660A (en) * | 2015-01-09 | 2015-05-06 | 广东瑞德智能科技股份有限公司 | Low-power-consumption short circuit protection circuit |
| CN107180527A (en) * | 2016-03-11 | 2017-09-19 | 包米勒公司 | Method and circuit arrangement for safe transmission of sensor signals |
| CN110044510A (en) * | 2019-05-17 | 2019-07-23 | 上海希形科技有限公司 | IGBT module temperature measurement circuit, temp measuring method and computer readable storage medium |
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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: 20140716 Termination date: 20171211 |