CN203707767U - Interface protection circuit, control circuit and electrical apparatus of current sensor - Google Patents
Interface protection circuit, control circuit and electrical apparatus of current sensor Download PDFInfo
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- CN203707767U CN203707767U CN201420062550.1U CN201420062550U CN203707767U CN 203707767 U CN203707767 U CN 203707767U CN 201420062550 U CN201420062550 U CN 201420062550U CN 203707767 U CN203707767 U CN 203707767U
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- 238000005070 sampling Methods 0.000 claims abstract description 44
- 230000001681 protective effect Effects 0.000 claims description 40
- 230000000694 effects Effects 0.000 abstract description 3
- 230000006641 stabilisation Effects 0.000 abstract 1
- 238000011105 stabilization Methods 0.000 abstract 1
- 239000000523 sample Substances 0.000 description 30
- 238000010586 diagram Methods 0.000 description 6
- 238000009833 condensation Methods 0.000 description 4
- 230000005494 condensation Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000005856 abnormality Effects 0.000 description 3
- 230000003750 conditioning effect Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000002706 hydrostatic effect Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
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Abstract
The utility model discloses a current sensor's interface protection circuit, control circuit and electrical apparatus. Wherein, the interface protection circuit of current sensor includes: the sampling end of the sampling circuit is connected with the current sensor, and the output end of the sampling circuit is connected with the controller; the current limiting circuit is connected between the current sensor and the sampling end of the sampling circuit; and the clamping circuit is connected with the sampling circuit and is used for controlling the sampling circuit to be below a preset voltage value. Through the utility model discloses, solved among the prior art problem that current sensor arouses the trouble easily, and then reached and improved current sensor job stabilization nature, carried out the effect protected to connecting current sensor's controller interface circuit.
Description
Technical field
The utility model relates to circuit field, in particular to a kind of interface protective circuit, control circuit and electrical equipment of current sensor.
Background technology
In existing household electrical appliance and commercial appliance, the number of sensors using is many, with business air conditioner circuit for instance, there is temperature sensor, fluid temperature sensor before condensation/heating, fluid temperature sensor after condensation/heating, hydrostatic sensor before condensation/heating, hydrostatic sensor after condensation/heating, air pressure probe etc.In these transducers, a conventional class transducer is 4-20mA electric current output transducer.Because number of sensors is many, controller mainboard limited space, sensor circuit is relatively simple.The simple voltage-regulator diode protection of some uses, what have does not even have a protective circuit.In the time that transducer breaks down, the transducer of normally exporting 4-20mA even can cause transducer two terminal shortcircuits more than may exporting 100mA.While thering is no protective circuit, current output sensor increase can burn out sampling resistor; While adopting voltage-regulator diode protection, short circuit sensor can cause power source loads to strengthen and damage power supply.
Easily cause the problem of fault for current sensor in correlation technique, not yet propose at present effective solution.
Utility model content
Main purpose of the present utility model is to provide a kind of interface protective circuit, control circuit and electrical equipment of current sensor, easily causes the problem of fault to solve current sensor in prior art.
According to an aspect of the present utility model, provide a kind of interface protective circuit of current sensor.
Comprise according to the interface protective circuit of current sensor of the present utility model: sample circuit, sampling end is connected with current sensor, and output is connected with controller; Current-limiting circuit, is connected between current sensor and the sampling end of sample circuit; And clamp circuit, be connected with sample circuit, for controlling sample circuit below predeterminated voltage value.
Further, interface protective circuit also comprises: filter circuit, is connected with sample circuit.
Further, sample circuit comprises: connector, is connected with current sensor; Sampling resistor, is connected between first output and first node of connector, wherein, and the node between the second output and signal ground that first node is connector; And analog to digital converter, be connected between Section Point and controller, wherein, Section Point is the node between the first output of sampling resistor and connector.
Further, the resistance value of sampling resistor meets
wherein, VCC is predeterminated voltage value, I
maxfor the maximum output current value of current sensor.
Further, clamp circuit comprises: DC power supply, and the output voltage size of DC power supply is predeterminated voltage value; The first diode, anode is connected with the first output of connector, and negative electrode is connected with DC power supply; And second diode, anode is connected with the first output of connector, and negative electrode is connected with sampling resistor.
Further, current-limiting circuit comprises the first current-limiting resistance, is connected between the first output of connector and the anode of the second diode.
Further, the resistance value of the first current-limiting resistance meets
wherein, V
sfor the supply voltage of current sensor, V
maxfor the maximum functional pressure drop of current sensor, V
d2it is the forward operating voltage of the second diode.
Further, sample circuit also comprises: the second current-limiting resistance, is connected between Section Point and analog to digital converter.
According on the other hand of the present utility model, provide a kind of control circuit.
Comprise according to control circuit of the present utility model: current sensor; Controller; And interface protective circuit, be connected between current sensor and controller, wherein, any interface protective circuit that interface protective circuit provides for the utility model foregoing.
According on the other hand of the present utility model, provide a kind of electrical equipment.
Comprise according to electrical equipment of the present utility model the control circuit that the utility model foregoing provides.
The utility model adopts the interface protective circuit of the current sensor with following structure: sample circuit, and sampling end is connected with current sensor, and output is connected with controller; Current-limiting circuit, is connected between current sensor and the sampling end of sample circuit; And clamp circuit, be connected with sample circuit, for controlling sample circuit below predeterminated voltage value.By current-limiting circuit is set, the current value in sampling circuit is limited, realized the in the situation that of current sensor output abnormality, avoid output current excessive and burn out sample circuit.By clamp circuit is set, the magnitude of voltage of sample circuit is limited, realized the in the situation that of current sensor short circuit, avoid sampled voltage to exceed the operating voltage of subsequent conditioning circuit.With this, solve current sensor in prior art and easily caused the problem of fault, and then reached raising current sensor job stability, the effect of protecting connecting the controller interface circuit of current sensor.
Accompanying drawing explanation
The accompanying drawing that forms the application's a part is used to provide further understanding of the present utility model, and schematic description and description of the present utility model is used for explaining the utility model, does not form improper restriction of the present utility model.In the accompanying drawings:
Fig. 1 is according to the schematic diagram of the interface protective circuit of the current sensor of the utility model embodiment;
Fig. 2 is according to the schematic diagram of the interface protective circuit of the current sensor of the utility model embodiment; And
Fig. 3 is according to the circuit diagram of the interface protective circuit of the current sensor of the utility model embodiment.
Embodiment
It should be noted that, in the situation that not conflicting, the feature in embodiment and embodiment in the application can combine mutually.Describe below with reference to the accompanying drawings and in conjunction with the embodiments the utility model in detail.
The utility model provides a kind of interface protective circuit of current sensor, below the interface protective circuit of current sensor that the utility model embodiment is provided do concrete introduction:
Fig. 1 is according to the schematic diagram of the interface protective circuit of the current sensor of the utility model embodiment, and as shown in Figure 1, this interface protective circuit mainly comprises sample circuit 10, current-limiting circuit 20, clamp circuit 30, wherein:
The sampling end of sample circuit 10 is connected with current sensor S, output and controller are (, CPU) be connected, mainly that the current signal that current sensor S is sent converts voltage signal to, and voltage signal is converted to after digital signal to controller, and then be converted into the value of the measuring-signal that transducer is corresponding.
Current-limiting circuit 20 is connected between current sensor S and the sampling end of sample circuit 10, for the protection of sample circuit 10, avoids the excessive sample circuit 10 that burns out of output current because of current sensor S.
Clamp circuit 30 is connected with sample circuit 10, for controlling sample circuit 10 below predeterminated voltage value, avoids the both end voltage of sample circuit 10 to exceed the operating voltage of subsequent control device, causes sample error.
The interface protective circuit of the current sensor that the utility model embodiment provides; by current-limiting circuit is set, the current value in sampling circuit is limited; realize the in the situation that of current sensor output abnormality, avoided output current excessive and burn out sample circuit.By clamp circuit is set, the magnitude of voltage of sample circuit is limited, realized the in the situation that of current sensor short circuit, avoid sampled voltage to exceed the operating voltage of subsequent conditioning circuit.With this, solve current sensor in prior art and easily caused the problem of fault, and then reached raising current sensor job stability, the effect of protecting connecting the controller interface circuit of current sensor.
Preferably; the interface protective circuit of the utility model embodiment also comprises filter circuit 40; this filter circuit 40 is connected with sample circuit 10, is mainly that the AC signal in transmission line is carried out to filtering, and this AC signal is mainly low frequency or the high-frequency ac clutter producing in transmission line.
By filter circuit being set in the interface protective circuit of current sensor, carry out filtering, realize the accuracy of the signal transmission that guarantees that transducer detects.
Particularly, in the utility model embodiment, filter circuit 40 can adopt the form of several Capacitance parallel connections to realize, and its physical circuit illustrates in following content again.
Fig. 2 is according to the schematic diagram of the interface protective circuit of the current sensor of the utility model embodiment; Fig. 3 is according to the circuit diagram of the interface circuit electric current of the current sensor of the utility model embodiment; as shown in Figures 2 and 3; (sample circuit 10 mainly comprises connector CN1, sampling resistor R3 and analog to digital converter; A/D converter) 11, wherein:
Connector CN1 is connected with current sensor S, that is, connector CN1 is for being connected to interface protective circuit by current sensor S.
Sampling resistor R3 is connected between the first output and first node of connector CN1, wherein, first node is the node between the second output and the signal ground of connector CN1, under current sensor S normal operation, current sensor S is output as the constant current output of 4-20mA, the sampling resistor R3 i.e. current signal of the 4-20mA to current sensor S output samples, and current signal is converted to voltage signal.
Analog to digital converter 11 is connected between Section Point and controller, and wherein, Section Point is the node between sampling resistor R3 and the first output of connector CN1, samples for the voltage signal that sampling resistor R3 is transmitted, and transfers to controller.
In the utility model embodiment, the resistance value size of sampling resistor R3 meets
wherein, VCC is predeterminated voltage value, I
maxfor the maximum output current value of current sensor S, the resistance value size of sampling resistor R3 is set to meet
be by the maximum working voltage of sampling resistor R3, be set to the maximum input voltage of the signal receiving end permission of controller, reach the object that as far as possible improves sampling precision.
Clamp circuit 30 mainly comprises DC power supply VCC, the first diode D1 and the second diode D2, wherein:
The output voltage size of DC power supply VCC is predeterminated voltage value VCC.
The anode of the first diode D1 is connected with the first output of connector CN1, and the negative electrode of the first diode D1 is connected with DC power supply VCC.
The anode of the second diode D2 is connected with the first output of connector CN1, and the negative electrode of the second diode D2 is connected with sampling resistor R3.
In the time of current sensor S operation irregularity, such as current sensor S short circuit, the voltage at the two ends of sampling resistor R3 may exceed the operating voltage of follow-up A/D circuit.Cause A/D sample error, affect sometimes the sampling on other road, even can burn A/D device.Adopt D1, the clamped circuit of double diode of D2 composition, by clamped sample circuit output voltage below VCC.
In the utility model embodiment, the first diode D1 is the diode that specification is identical with the second diode D2, and the rated current of each diode is greater than the maximum operating currenbt I of current sensor S
max.
When normal operation of sensor, the voltage at sampling resistor R3 two ends is less than VCC, D1 cut-off, and D2 conducting, the electric current that flows through sampling resistor R3 is the output current of current sensor S; The voltage that A is ordered equals the forward conduction voltage sum of voltage and the D2 of sampling resistor R3.In the time that current sensor S breaks down, the voltage that A is ordered is higher, D1 conducting, and the voltage clamping that A is ordered is in the forward conduction voltage sum of VCC and D1.Therefore, as long as D1 is identical with the model of D2, just can guarantee that the output voltage at sampling resistor R3 two ends is no more than VCC, A/D circuit can normally be worked.
Current-limiting circuit 20 comprises the first current-limiting resistance R1, is connected between the first output of connector CN1 and the anode of the second diode D2.The resistance value of the first current-limiting resistance R1 meets
wherein, V
sfor the supply voltage of current sensor, V
maxfor the maximum functional pressure drop of current sensor, V
d2it is the forward operating voltage of the second diode D2.
Current sensor, in when work, may, due to device failure or other reason, make current sensor output abnormality, and the electric current that causes flowing through sampling resistor R3 is excessive and burn R3.For this reason, at a current-limiting resistance R1 of output serial connection of current sensor, be used for protecting sampling resistor R3.
Further, sample circuit 10 also comprises the second current-limiting resistance, this second current-limiting resistance R4 is connected between Section Point and analog to digital converter 11, for the voltage signal that transfers to analog to digital converter 11 is carried out to step-down, avoid sampled voltage to exceed the operating voltage of subsequent conditioning circuit, further improve the job stability of current sensor.
The utility model embodiment also provides a kind of control circuit; control circuit comprises current sensor and controller; and be connected to the interface protective circuit between current sensor and controller, the interface protective circuit of any current sensor that this interface protective circuit provides for the utility model foregoing.
By interface protective circuit is set in control circuit, to realize for number of sensors morely, the control circuit of operational environment complexity is protected, and this kind of control circuit has advantages of that job stability is high.
In addition, the utility model embodiment also provides a kind of electrical equipment, and this electrical equipment comprises the control circuit that the utility model foregoing provides.
As can be seen from the above description, the utility model has been realized the job stability that improves current sensor, and the controller interface circuit that connects current sensor is protected.
The foregoing is only preferred embodiment of the present utility model, be not limited to the utility model, for a person skilled in the art, the utility model can have various modifications and variations.All within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection range of the present utility model.
Claims (10)
1. an interface protective circuit for current sensor, is characterized in that, comprising:
Sample circuit (10), sampling end is connected with described current sensor, and output is connected with controller;
Current-limiting circuit (20), is connected between described current sensor and the sampling end of described sample circuit (10); And
Clamp circuit (30), is connected with described sample circuit (10), for controlling described sample circuit (10) below predeterminated voltage value.
2. interface protective circuit according to claim 1, is characterized in that, described interface protective circuit also comprises:
Filter circuit (40), is connected with described sample circuit (10).
3. interface protective circuit according to claim 1, is characterized in that, described sample circuit (10) comprising:
Connector (CN1), is connected with described current sensor;
Sampling resistor (R3), is connected between first output and first node of described connector (CN1), and wherein, described first node is the node between the second output and the signal ground of described connector (CN1); And
Analog to digital converter (11), is connected between Section Point and described controller, and wherein, described Section Point is the node between described sampling resistor (R3) and the first output of described connector (CN1).
4. interface protective circuit according to claim 3, is characterized in that, the resistance value of described sampling resistor (R3) meets
wherein, VCC is described predeterminated voltage value, I
maxfor the maximum output current value of described current sensor.
5. interface protective circuit according to claim 3, is characterized in that, described clamp circuit (30) comprising:
DC power supply (VCC), the output voltage size of described DC power supply (VCC) is described predeterminated voltage value;
The first diode (D1), anode is connected with the first output of described connector (CN1), and negative electrode is connected with described DC power supply (VCC); And
The second diode (D2), anode is connected with the first output of described connector (CN1), and negative electrode is connected with described sampling resistor (R3).
6. interface protective circuit according to claim 5, is characterized in that, described current-limiting circuit (20) comprises the first current-limiting resistance (R1), is connected between the first output of described connector (CN1) and the anode of described the second diode (D2).
7. interface protective circuit according to claim 6, is characterized in that, the resistance value of described the first current-limiting resistance (R1) meets
wherein, V
sfor the supply voltage of described current sensor, V
maxfor the maximum functional pressure drop of described current sensor, V
d2for the forward operating voltage of described the second diode (D2).
8. interface protective circuit according to claim 3, is characterized in that, described sample circuit (10) also comprises:
The second current-limiting resistance (R4), is connected between described Section Point and described analog to digital converter (11).
9. a control circuit, is characterized in that, comprising:
Current sensor;
Controller; And
Interface protective circuit, is connected between described current sensor and described controller, and wherein, described interface protective circuit is the interface protective circuit described in any one in claim 1 to 8.
10. an electrical equipment, is characterized in that, comprises control circuit claimed in claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420062550.1U CN203707767U (en) | 2014-02-11 | 2014-02-11 | Interface protection circuit, control circuit and electrical apparatus of current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420062550.1U CN203707767U (en) | 2014-02-11 | 2014-02-11 | Interface protection circuit, control circuit and electrical apparatus of current sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203707767U true CN203707767U (en) | 2014-07-09 |
Family
ID=51058149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420062550.1U Expired - Lifetime CN203707767U (en) | 2014-02-11 | 2014-02-11 | Interface protection circuit, control circuit and electrical apparatus of current sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203707767U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104617570A (en) * | 2015-01-08 | 2015-05-13 | 武汉电信器件有限公司 | Large-light input type A/D (Analog to Digital) sampling overvoltage protection circuit |
| CN107820530A (en) * | 2015-05-22 | 2018-03-20 | 海德里尔美国配送有限责任公司 | System and method for sensing the engagement in dangerous grading environment |
-
2014
- 2014-02-11 CN CN201420062550.1U patent/CN203707767U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104617570A (en) * | 2015-01-08 | 2015-05-13 | 武汉电信器件有限公司 | Large-light input type A/D (Analog to Digital) sampling overvoltage protection circuit |
| CN107820530A (en) * | 2015-05-22 | 2018-03-20 | 海德里尔美国配送有限责任公司 | System and method for sensing the engagement in dangerous grading environment |
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| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140709 |