CN205103305U - Hourglass current detection circuit of difference filtering - Google Patents
Hourglass current detection circuit of difference filtering Download PDFInfo
- Publication number
- CN205103305U CN205103305U CN201520815213.XU CN201520815213U CN205103305U CN 205103305 U CN205103305 U CN 205103305U CN 201520815213 U CN201520815213 U CN 201520815213U CN 205103305 U CN205103305 U CN 205103305U
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- resistance
- operational amplifier
- electrically connected
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- side winding
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Abstract
The utility model discloses a hourglass current detection circuit of difference filtering, power supply is coupled to the high frequency ripple in the leakage current signal among its filtering current transformer detection circuitry. Including current transformer detection circuitry, it is used for exporting differential voltage signal, with the difference filter circuit that the current transformer detection circuitry electricity is connected, the different name end of two windings of current transformer is connected respectively to two terminals of difference filter circuit, can carry out effective filtering to the high frequency ripple that power supply was coupled to in the leakage current signal.
Description
Technical field
The utility model belongs to the technical field of leakage current detection circuit, specifically relates to a kind of leakage current detection circuit of differential filtering.
Background technology
At present, existing a kind of leakage current detection circuit, its output voltage signal is used for, for ADC sampling, comprising current transformer testing circuit, difference scaling circuit, wave filter and absolute value circuit.Wherein, current transformer testing circuit, it is for output difference divided voltage signal.Differential voltage signal exports the voltage signal being suitable for ADC sampling through difference scaling circuit, wave filter and absolute value circuit.In current transformer testing circuit, it adopts+5V power supply will power to current transformer secondary, and this undesired signal can be coupled in leakage current test signal, if do not carry out effective filtering, can reduce the accuracy of detection of whole system.
Summary of the invention
The purpose of this utility model is to provide a kind of leakage current detection circuit of differential filtering, and in its filtering current transformer testing circuit, power supply is coupled to the high frequency ripple in leakage current signal.
For solving the problems of the technologies described above, the purpose of this utility model is achieved in that a kind of leakage current detection circuit of differential filtering, comprises current transformer testing circuit, and it is for output difference divided voltage signal, the differential filtering circuit be electrically connected with described current transformer testing circuit, described differential filtering circuit comprises the 3rd resistance and the 4th resistance, power supply is electrically connected with the in-phase input end of the first operational amplifier through described 3rd resistance and the 4th resistance, the inverting input of the first operational amplifier is electrically connected with one end of the 8th resistance, common port between the inverting input of the first operational amplifier and the 8th resistance is through the 9th resistance eutral grounding, the output terminal of the first operational amplifier is through the second capacity earth, the in-phase input end of the first operational amplifier is electrically connected through the output terminal of the first electric capacity with the first operational amplifier, the output terminal of the first operational amplifier is electrically connected with the inverting input of the second operational amplifier through the 6th resistance, common port between the inverting input of the second operational amplifier and the 6th resistance is through the 7th resistance eutral grounding, common port between 3rd resistance and the 4th resistance is electrically connected with the in-phase input end of the second operational amplifier through the 5th resistance, one end of 3rd electric capacity is electrically connected with the in-phase input end of the second operational amplifier, the other end of the 3rd electric capacity is electrically connected with the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is through the 4th capacity earth, the output terminal of the second operational amplifier is electrically connected with the other end of the 8th resistance.
On the basis of such scheme and as the preferred version of such scheme: described first operational amplifier, the second operational amplifier all adopt single power supply mode.
On the basis of such scheme and as the preferred version of such scheme: described current transformer testing circuit comprises current transformer, described current transformer comprises magnetic core, magnetic core is wound with former limit winding, the first vice-side winding and the second vice-side winding, first vice-side winding is electrically connected with the second vice-side winding through the first resistance, the second resistance, and the common port between the first resistance and the second resistance connects power supply.
The leakage current detection circuit of differential filtering according to claim 3, it is characterized in that: described former limit winding only has a circle, described first vice-side winding and the second vice-side winding all have 100 circles, and the first vice-side winding and the second vice-side winding all adopt enameled wire coiling to form.
On the basis of such scheme and as the preferred version of such scheme: described power supply is+5V.
The utility model gives prominence to compared to existing technology and useful technique effect is:
The leakage current detection circuit of differential filtering of the present utility model, have employed the structure of differential filtering circuit, is coupled to the high frequency ripple in leakage current signal with power supply in filtering current transformer testing circuit.This leakage current detection circuit is used for, in the leak current detection device for ADC sampling, its accuracy of detection can be ensured.
Accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model.
Embodiment
The utility model is further described with specific embodiment below in conjunction with accompanying drawing, see Fig. 1;
It should be noted that, " first ", " second ", " the 3rd ", " the 4th ", " the 5th ", " the 6th ", " the 7th ", " the 8th ", " the 9th " etc. alleged in the present embodiment are not to the restriction quantitatively of correlation technique feature, but in order to distinguish the name that generic technical characteristic is made.
The present embodiment provides a kind of leakage current detection circuit of differential filtering, comprises current transformer testing circuit and differential filtering circuit.Wherein, current transformer testing circuit is used for output difference divided voltage signal; The differential filtering circuit be electrically connected with described current transformer, it is coupled to the high frequency ripple in leakage current signal for power supply in filtering current transformer testing circuit.
Above-mentioned differential filtering circuit comprises the 3rd resistance R3 and the 4th resistance R4, power supply is electrically connected with the in-phase input end of the first operational amplifier through described 3rd resistance R3 and the 4th resistance R4, the inverting input of the first operational amplifier is electrically connected with one end of the 8th resistance R8, common port between the inverting input of the first operational amplifier and the 8th resistance R8 is through the 9th resistance R9 ground connection, the output terminal of the first operational amplifier is through the second electric capacity C2 ground connection, the in-phase input end of the first operational amplifier is electrically connected with the output terminal of the first operational amplifier through the first electric capacity C1, the output terminal of the first operational amplifier is electrically connected with the inverting input of the second operational amplifier through the 6th resistance R6, common port between the inverting input of the second operational amplifier and the 6th resistance R6 is through the 7th resistance R7 ground connection, common port between 3rd resistance R3 and the 4th resistance R4 is electrically connected with the in-phase input end of the second operational amplifier through the 5th resistance R5, one end of 3rd electric capacity C3 is electrically connected with the in-phase input end of the second operational amplifier, the other end of the 3rd electric capacity C3 is electrically connected with the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is through the 4th electric capacity C4 ground connection.The output terminal of the second operational amplifier is electrically connected with the other end of the 8th resistance R8.In the present embodiment, described first operational amplifier, the second operational amplifier all adopt single power supply mode.In this differential filtering circuit, common port between the output terminal of the second operational amplifier and the 8th resistance and the common port between the output terminal of the first operational amplifier and the 6th resistance, as output terminal, are respectively used to the different name end electrical connection with the first vice-side winding and the second vice-side winding.In high-power system application, power supply+5V can be disturbed by power circuit, comprises high frequency ripple, because+5V power supply powers to current transformer secondary, this undesired signal can be coupled in leakage current test signal, if do not carry out effective filtering, can reduce the accuracy of detection of whole system.Two terminals of differential filtering circuit connect the different name end of current transformer two windings respectively, can carry out effective filtering to the high frequency ripple that power supply is coupled in leakage current signal.
In the present embodiment, as shown in fig. 1, described current transformer testing circuit comprises current transformer, and described current transformer comprises magnetic core, and magnetic core is wound with former limit winding, the first vice-side winding and the second vice-side winding.Usually, former limit winding is 1 circle, and it is formed by the magnetic core of former limit winding through current transformer, and the first vice-side winding and the second vice-side winding adopt 100 circle enameled wire coilings to form respectively.First vice-side winding is electrically connected with the second vice-side winding through the first resistance R1, the second resistance R2, and the common port between the first resistance and the second resistance connects power supply.In the present embodiment, power supply is+5V.In this current transformer testing circuit, the common port between the first vice-side winding and the first resistance and the common port between the second vice-side winding and the second resistance as output terminal, with output difference divided voltage signal.During work, secondary current is former limit 1/100, and the 200 Ω resistance that this electric current flows through vice-side winding series connection produce pressure drop, and current signal is converted to voltage signal.
Above-described embodiment is only preferred embodiment of the present utility model, not limits protection domain of the present utility model according to this, therefore: all equivalence changes done according to structure of the present utility model, shape, principle, all should be covered by within protection domain of the present utility model.
Claims (5)
1. a leakage current detection circuit for differential filtering, is characterized in that: comprise current transformer testing circuit, and it is for output difference divided voltage signal;
The differential filtering circuit be electrically connected with described current transformer testing circuit, described differential filtering circuit comprises the 3rd resistance and the 4th resistance, power supply is electrically connected with the in-phase input end of the first operational amplifier through described 3rd resistance and the 4th resistance, the inverting input of the first operational amplifier is electrically connected with one end of the 8th resistance, common port between the inverting input of the first operational amplifier and the 8th resistance is through the 9th resistance eutral grounding, the output terminal of the first operational amplifier is through the second capacity earth, the in-phase input end of the first operational amplifier is electrically connected through the output terminal of the first electric capacity with the first operational amplifier, the output terminal of the first operational amplifier is electrically connected with the inverting input of the second operational amplifier through the 6th resistance, common port between the inverting input of the second operational amplifier and the 6th resistance is through the 7th resistance eutral grounding, common port between 3rd resistance and the 4th resistance is electrically connected with the in-phase input end of the second operational amplifier through the 5th resistance, one end of 3rd electric capacity is electrically connected with the in-phase input end of the second operational amplifier, the other end of the 3rd electric capacity is electrically connected with the output terminal of the second operational amplifier, the output terminal of the second operational amplifier is through the 4th capacity earth, the output terminal of the second operational amplifier is electrically connected with the other end of the 8th resistance.
2. the leakage current detection circuit of differential filtering according to claim 1, is characterized in that: described first operational amplifier, the second operational amplifier all adopt single power supply mode.
3. the leakage current detection circuit of differential filtering according to claim 1, it is characterized in that: described current transformer testing circuit comprises current transformer, described current transformer comprises magnetic core, magnetic core is wound with former limit winding, the first vice-side winding and the second vice-side winding, first vice-side winding is electrically connected with the second vice-side winding through the first resistance, the second resistance, and the common port between the first resistance and the second resistance connects power supply.
4. the leakage current detection circuit of differential filtering according to claim 3, it is characterized in that: described former limit winding only has a circle, described first vice-side winding and the second vice-side winding all have 100 circles, and the first vice-side winding and the second vice-side winding all adopt enameled wire coiling to form.
5. the leakage current detection circuit of differential filtering according to claim 3, is characterized in that: described power supply is+5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520815213.XU CN205103305U (en) | 2015-10-14 | 2015-10-14 | Hourglass current detection circuit of difference filtering |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520815213.XU CN205103305U (en) | 2015-10-14 | 2015-10-14 | Hourglass current detection circuit of difference filtering |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205103305U true CN205103305U (en) | 2016-03-23 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520815213.XU Expired - Fee Related CN205103305U (en) | 2015-10-14 | 2015-10-14 | Hourglass current detection circuit of difference filtering |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205103305U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244257A (en) * | 2019-07-26 | 2019-09-17 | 华立科技股份有限公司 | The earth detector and method of electric energy meter |
-
2015
- 2015-10-14 CN CN201520815213.XU patent/CN205103305U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110244257A (en) * | 2019-07-26 | 2019-09-17 | 华立科技股份有限公司 | The earth detector and method of electric energy meter |
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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: 20160323 Termination date: 20181014 |