CN202631606U - Current detection apparatus - Google Patents
Current detection apparatus Download PDFInfo
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- CN202631606U CN202631606U CN 201220109849 CN201220109849U CN202631606U CN 202631606 U CN202631606 U CN 202631606U CN 201220109849 CN201220109849 CN 201220109849 CN 201220109849 U CN201220109849 U CN 201220109849U CN 202631606 U CN202631606 U CN 202631606U
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Abstract
The utility model discloses a current detection apparatus applied in electric power electronic direct current transformation. The current detection apparatus mainly comprises an inductor (100), an RC network (110), an amplification circuit (210), a charge pump circuit (220), a first level differential circuit (310) and a second level differential circuit (320). The current flowing through the inductor (100) is conversed to a voltage signal to be output to the amplification circuit (210) the an RC network; the amplification circuit (210) amplifies the input voltage signal and outputs the amplified signal to the charge pump circuit (220); the amplification circuit (210) is isolated from the ground level through the charge pump circuit (220), and thereby the potential floating function is achieved; and the conduction voltage difference introduced by the charge pump circuit (220) is eliminated under the common effect of the first level differential circuit (310) and the second level differential circuit (320). According to the utility model, the current detection apparatus can be used for lossless detection of inductance current in a direct current transformation circuit under a high pressure condition.
Description
Technical field
The utility model electronic circuit technology, particularly current sensing means can be used for the detection of power electronic system to electric current.
Background technology
When technology such as enforcement current-mode control, overcurrent protection, system's parallel current-sharing, all must use the detection technique of inductive current in the power electronic system.
Common inductive current detection method has series connection inspection leakage resistance method, current transformer method, insulated gate transistor MOSFET cellular detection method and inductance equivalent series resistance detection method.
Series connection inspection leakage resistance method, as shown in Figure 1, it is that inspection leakage resistance 1 is connected with load 2, according to Ohm law, can confirm electric current to be detected as long as detect the voltage at inspection leakage resistance 1 two ends.The defective of this method is that loss is too big, and particularly in big current detecting, loss can not be ignored.
The current transformer method is according to electromagnetic induction principle, utilizes mutual inductor to carry out current detecting, and a winding string is measured in the circuit of electric current at needs, and Secondary Winding is serially connected in measurement instrument and protects in the loop.Current transformer can convert the bigger primary current of numerical value into numerical value less secondary current through certain no-load voltage ratio.The defective of this method is to detect DC current.
Insulated gate transistor MOSFET cellular detection method is the power MOSFET side in testing circuit and meet a detection MOSFET.The defective of this method is that the applicable frequency span of institute is too narrow, and and the detection MOSFET that connects can bring very big error to original power MOSFET in the circuit.
Inductance equivalent series resistance detection method, as shown in Figure 2, the electric current that this method will flow through inductance is converted into voltage signal, obtains current value through detectable voltage signals.Because the value of inductance equivalent series resistance ESR is very little, need detection signal be amplified with operational amplifier.Owing to receive the withstand voltage restriction of operational amplifier, cause this method can not be advantageously applied to the high pressure occasion.
The utility model content
The purpose of the utility model is the deficiency to above-mentioned prior art, proposes a kind of current sensing means, to reduce to detect loss and to the influence of detected circuit, is implemented under the high pressure occasion the accurate detection to dc signal and ac signal.
For realizing above-mentioned purpose, the current sensing means of the utility model comprises inductance, and RC network is characterized in that:
The output terminal of RC network is connected with the voltage detecting circuit that current potential floats, and is used for detecting the voltage difference that RC network detects the electric capacity two ends; The output terminal of the voltage detecting circuit that this current potential floats is connected with difference ratio computing circuit, is used for the output of amplifying voltage testing circuit, and the reference planes of output voltage values are revert to the ground level is benchmark;
The voltage detecting circuit that described current potential floats comprises: amplifying circuit and charge pump circuit; The input end of amplifying circuit is parallelly connected with the detection electric capacity in the RC network; The input end of charge pump circuit and the output of amplifying circuit are connected in series;
Described difference ratio computing circuit comprises: first order difference channel and second level difference channel; The input end of first order difference channel links to each other with the output terminal of charge pump circuit; The input end of the output terminal of first order difference channel and second level difference channel connects; The output terminal of second level difference channel is as the output of whole testing circuit.
The utility model has been owing to owing to adopted in the power electronic system original power inductance that electric current is measured, made full use of the equivalent series resistance of inductance, makes not add new loss in the testing circuit, thereby reaches the purpose of lossless measurement; Because the utility model has added charge pump circuit in the voltage detecting loop, the voltage in voltage detecting loop is floated, so this circuit can be applied in the high pressure occasion well simultaneously; Because the utility model has added difference ratio computing circuit, eliminated the voltage drop in the charge pump circuit in addition, and output voltage is got back to the ground level is benchmark to output voltage influence.
Description of drawings
Fig. 1 is the existing current detection circuit structured flowchart of using the inspection leakage resistance;
Fig. 2 is the current detection circuit structured flowchart of existing application inductance equivalent series resistance;
Fig. 3 is the structured flowchart of the utility model;
Fig. 4 is the circuit structure schematic diagram of the utility model.
Embodiment
For making the purpose of the utility model, technical scheme and advantage are clearer, below in conjunction with accompanying drawing, utilize specific embodiment, and the utility model is done further detailed explanation.
The utility model embodiment makes that through to detecting the coupling of electric capacity and build-out resistor in the RC network voltage difference at electric capacity two ends is linear with the electric current of the inductance of flowing through, and utilizes this characteristic to carry out current detecting.
With reference to Fig. 3, the current detection circuit of the utility model comprises voltage detecting circuit 200 and difference ratio computing circuit 300 that inductance 100, RC network 110, current potential float.Wherein voltage detecting circuit 200 comprises amplifying circuit 210 and charge pump circuit 220, and difference ratio computing circuit 300 comprises first order difference channel 310 and second level difference channel 320.The input end of this RC network 110 is connected in parallel on the two ends of inductance 100; Output terminal links to each other with the input end of amplifying circuit 210; The output terminal of this amplifying circuit 210 links to each other with the input end of charge pump circuit 220; The output terminal of this charge pump circuit 220 links to each other with the input end of first order difference channel 310, and the output terminal of this first order difference channel 310 links to each other with the input end of second level difference channel 320, and the output terminal of this second level difference channel 320 is as the output of whole testing circuit.To the flow through electric current of inductance of RC network 110 is converted into voltage signal, outputs to amplifying circuit 210; The voltage signal of 210 pairs of inputs of amplifying circuit amplifies, and the signal after will amplifying is exported to charge pump circuit 220; When the inductance floating voltage is noble potential, through charge pump circuit 220 amplifying circuit 210 and difference ratio computing circuit 300 are isolated, amplifying circuit 210 is reference planes with the floating voltage of inductance 100, guarantees that operational amplifier 211 is not breakdown; When the inductance floating voltage is electronegative potential, make the output of amplifying circuit 210 pass to difference ratio computing circuit 300 through charge pump circuit 220; By the acting in conjunction of first order difference channel 310 and second level difference channel 320, it is poor to eliminate the forward voltage of introducing in the charge pump circuit, and output voltage is returned to the ground level is reference planes.
With reference to Fig. 4, the syndeton of the entire circuit of the utility model is following:
Said RC network 110 comprises build-out resistor 111 and detects electric capacity 112; One end of build-out resistor 111 is connected with detection electric capacity 112, and the other end is connected with the power end of inductance 100, and the other end that detects electric capacity 112 links to each other with the load end of inductance 100; The two ends of detection electric capacity 112 link to each other with the input of amplifying circuit 210 as the output of RC network, and the terminal potential that detection electric capacity 112 links to each other with inductance floats, and the other end current potential that links to each other with build-out resistor does not float.
Said amplifying circuit 210 comprises operational amplifier 211, first resistance 212, second resistance 213 and charging capacitor 214; The in-phase input end of operational amplifier 211 links to each other with the non-floating end of current potential that detects electric capacity 112; Inverting input links to each other with the current potential floating end that detects electric capacity 112 through second resistance 213; Output terminal links to each other with charge pump circuit; Simultaneously the output signal of operational amplifier 211 feeds back to the inverting input of this operational amplifier 211 through first resistance 212, and this operational amplifier amplifies input signal with the form that homophase amplifies; Charging capacitor 214 is as the power supply of operational amplifier 211, is connected between the negative power end of positive power source terminal and this operational amplifier 211 of operational amplifier 211; Because the current potential of charging capacitor 214 floats with the floating voltage that detects electric capacity 112, guarantee that amplifying circuit 210 reference planes current potentials float.
Said charge pump circuit 220 comprises first diode 221, second diode 222 and the 3rd diode 223; The negative electrode of first diode 221 links to each other with the output terminal of operational amplifier 211, and the negative electrode of second diode 222 links to each other with the current potential floating end that detects electric capacity 112, and the negative electrode of the 3rd diode 223 links to each other with the positive power source terminal of operational amplifier 211; Because the characteristic of the single-phase conducting of diode; Make and have only when the anode voltage of diode is higher than negative electrode; The conducting of diode ability, promptly when the floating voltage that detects electric capacity 112 was noble potential, 3 diodes all ended; Have only when the floating voltage that detects electric capacity 112 is lower than the anode of diode, 3 diodes could said conducting.Through the effect of described 3 diodes 221,222,223, said voltage detecting circuit (200) and ground level are isolated, thereby reach the function that current potential floats.
Said first order difference channel 310 comprises first order operational amplifier 313, first divider resistance 311, second divider resistance 312, the 3rd resistance 314 and the 4th resistance 315; The in-phase input end of first order operational amplifier 313 links to each other with the anode of second diode 222, inverting input through the 3rd resistance 314 with link to each other publicly, output terminal links to each other with the input end of second level difference channel 320; The 4th resistance 315 is connected between the inverting input and output terminal of said first order operational amplifier 313; First divider resistance 311 is connected between the anode of in-phase input end and power supply 326 of first order operational amplifier 313; Second divider resistance 312 is connected between the in-phase input end and public ground of first order operational amplifier 313; Bleeder circuit through first divider resistance 311 and second divider resistance, 312 compositions; Make second diode 222 in the charge pump circuit 220 obtain to be higher than the voltage of charge pump circuit tube voltage drop; Make second diode 222 end conducting when the inductance floating voltage is electronegative potential during for noble potential at the inductance floating voltage.This first order operational amplifier 313, its in-phase input end links to each other with the anode of second diode 222, inverting input through the 3rd resistance 314 with link to each other publicly, output terminal links to each other with the input end of second level difference channel 320; The 4th resistance 315 is connected between the inverting input and output terminal of this first order operational amplifier 313.
Said second level difference channel 320 comprises second level operational amplifier 323, the 3rd divider resistance 321, the 4th divider resistance 322, the 5th resistance 324 and the 6th resistance 325; The in-phase input end of second level operational amplifier (323) links to each other with the anode of first diode (221); Inverting input links to each other with the output of first order operational amplifier (313) through the 5th resistance (324), and output terminal is as the output of whole testing circuit; The 6th resistance (325) is connected between the inverting input and output terminal of said second level operational amplifier (323); The 3rd divider resistance 321 is connected between the anode of in-phase input end and power supply 326 of second level operational amplifier 323; The 4th divider resistance 322 is connected between the in-phase input end and public ground of second level operational amplifier 323; Bleeder circuit through the 3rd divider resistance 321 and the 4th divider resistance 322 compositions; Make first diode 221 in the charge pump circuit 220 obtain to be higher than the voltage of charge pump circuit tube voltage drop; Make the diode 222 of winning end conducting when the inductance floating voltage is electronegative potential during for noble potential at the inductance floating voltage.The in-phase input end of this second level operational amplifier 323 links to each other with the anode of first diode 222, and inverting input links to each other with the output of first order operational amplifier 313 through the 5th resistance 324, and output terminal is as the output of whole testing circuit; The 6th resistance 325 is connected between the inverting input and output terminal of said second level operational amplifier 323.
By the acting in conjunction of first order difference channel 310 and second level difference channel 320, it is poor to eliminate the forward voltage of introducing in the charge pump circuit, and output voltage is returned to the ground level is reference planes.
Claims (6)
1. a current sensing means comprises inductance (100), and RC network (110) is characterized in that:
The output terminal of RC network (110) is connected with the voltage detecting circuit (200) that current potential floats, and is used for detecting the voltage difference that RC network (110) detects the electric capacity two ends; The output terminal of the voltage detecting circuit (200) that this current potential floats is connected with difference ratio computing circuit (300), is used for the output of amplifying voltage testing circuit (200), and the reference planes of output voltage values are returned to the ground level is benchmark;
The voltage detecting circuit (200) that described current potential floats comprising: amplifying circuit (210) and charge pump circuit (220); The input end of amplifying circuit (210) is parallelly connected with the detection electric capacity in the RC network; The output of the input end of charge pump circuit (220) and amplifying circuit (210) is connected in series;
Described difference ratio computing circuit (300) comprising: first order difference channel (310) and second level difference channel (320); The input end of first order difference channel (310) links to each other with the output terminal of charge pump circuit (220); The output terminal of first order difference channel (310) links to each other with the input end of second level difference channel (320); The output terminal of second level difference channel (320) is as the output of whole testing circuit.
2. current sensing means as claimed in claim 1; It is characterized in that; RC network (110) comprising: build-out resistor (111) is connected with detection electric capacity (112) with detection electric capacity (112) a, end of this build-out resistor (111), and the other end is connected with the power end of inductance (100); The other end that detects electric capacity (112) links to each other with the load end of inductance (100), detects the electric capacity two ends and links to each other with amplifying circuit (210) as the output terminal of RC network again.
3. current sensing means as claimed in claim 1 is characterized in that, amplifying circuit (210) comprising: operational amplifier (211), first resistance (212), second resistance (213) and charging capacitor (214); The in-phase input end of operational amplifier (211) links to each other with the non-floating end of current potential that detects electric capacity (112), and inverting input links to each other with the current potential floating end that detects electric capacity (112) through second resistance (213), and output terminal links to each other with charge pump circuit; First resistance (212) is connected between the output terminal and inverting input of operational amplifier (211); One end of charging capacitor (214) links to each other with the positive power source terminal of operational amplifier (211), and the other end links to each other with the negative power end of operational amplifier (211).
4. current sensing means as claimed in claim 1 is characterized in that, described charge pump circuit (220) comprising: first diode (221), second diode (222), the 3rd diode (223); The negative electrode of this first diode (221) links to each other with the output terminal of said operational amplifier (211); The negative electrode of second diode (222) links to each other with the current potential floating end of said detection electric capacity (112); The negative electrode of the 3rd diode (223) links to each other with the positive power source terminal of said operational amplifier (211); Effect through described 3 diodes (221), (222), (223); Said voltage detecting circuit (200) and ground level are isolated, thereby reach the function that current potential floats.
5. current sensing means as claimed in claim 1; It is characterized in that said first order difference channel (310) comprising: first order operational amplifier (313), first divider resistance (311), second divider resistance (312), the 3rd resistance (314) and the 4th resistance (315); The in-phase input end of first order operational amplifier (313) links to each other with the anode of second diode (222), inverting input through the 3rd resistance (314) with link to each other publicly, output terminal links to each other with the input end of second level difference channel (320); The 4th resistance (315) is connected between the inverting input and output terminal of said first order operational amplifier (313); First divider resistance (311) is connected between the anode of in-phase input end and power supply (326) of said first order operational amplifier (313); Second divider resistance (312) is connected between the in-phase input end and public ground of first order operational amplifier (313), through the effect of said divider resistance (311) and (312), makes the diode (222) in the charge pump circuit (220) obtain forward voltage.
6. current sensing means as claimed in claim 1; It is characterized in that said second level difference channel (320) comprising: second level operational amplifier (323), the 3rd divider resistance (321), the 4th divider resistance (322), the 5th resistance (324) and the 6th resistance (325); The in-phase input end of second level operational amplifier (323) links to each other with the anode of first diode (221), and inverting input links to each other with the output of first order operational amplifier (313) through the 5th resistance (324), and output terminal is as the output of whole testing circuit; The 6th resistance (325) is connected between the inverting input and output terminal of said second level operational amplifier (323); The 3rd divider resistance (321) is connected between the anode of in-phase input end and power supply (326) of said second level operational amplifier (323); The 4th divider resistance (322) is connected between the in-phase input end and public ground of second level operational amplifier (323), through the effect of said divider resistance (321) and (322), makes first diode (221) in the charge pump circuit (220) obtain forward voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220109849 CN202631606U (en) | 2012-03-22 | 2012-03-22 | Current detection apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220109849 CN202631606U (en) | 2012-03-22 | 2012-03-22 | Current detection apparatus |
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| CN202631606U true CN202631606U (en) | 2012-12-26 |
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| CN 201220109849 Expired - Fee Related CN202631606U (en) | 2012-03-22 | 2012-03-22 | Current detection apparatus |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102621369A (en) * | 2012-03-22 | 2012-08-01 | 西安电子科技大学 | Inductance ESR (equivalent series resistance) based electric current detection circuit with potential floating function |
| CN108315741A (en) * | 2018-02-08 | 2018-07-24 | 中国特种设备检测研究院 | A kind of pipe current detection device |
| CN108761284A (en) * | 2018-05-18 | 2018-11-06 | 北京华峰测控技术股份有限公司 | Drain leakage test circuit in field-effect tube breakdown voltage characteristics and method |
| CN109459600A (en) * | 2018-12-25 | 2019-03-12 | 北京华峰测控技术股份有限公司 | A kind of floating wide-range voltage measuring circuit |
| WO2019056299A1 (en) * | 2017-09-22 | 2019-03-28 | 深圳传音通讯有限公司 | Circuit for measuring zero-voltage-drop current |
-
2012
- 2012-03-22 CN CN 201220109849 patent/CN202631606U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102621369A (en) * | 2012-03-22 | 2012-08-01 | 西安电子科技大学 | Inductance ESR (equivalent series resistance) based electric current detection circuit with potential floating function |
| WO2019056299A1 (en) * | 2017-09-22 | 2019-03-28 | 深圳传音通讯有限公司 | Circuit for measuring zero-voltage-drop current |
| CN108315741A (en) * | 2018-02-08 | 2018-07-24 | 中国特种设备检测研究院 | A kind of pipe current detection device |
| CN108315741B (en) * | 2018-02-08 | 2020-04-03 | 中国特种设备检测研究院 | Pipeline current detection device |
| CN108761284A (en) * | 2018-05-18 | 2018-11-06 | 北京华峰测控技术股份有限公司 | Drain leakage test circuit in field-effect tube breakdown voltage characteristics and method |
| CN109459600A (en) * | 2018-12-25 | 2019-03-12 | 北京华峰测控技术股份有限公司 | A kind of floating wide-range voltage measuring circuit |
| CN109459600B (en) * | 2018-12-25 | 2024-04-30 | 北京华峰测控技术股份有限公司 | Floating wide-range voltage measurement circuit |
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Legal Events
| Date | Code | Title | Description |
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| 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: 20121226 Termination date: 20160322 |