CN202362349U - Lamp current sampling circuit of inverter - Google Patents
Lamp current sampling circuit of inverter Download PDFInfo
- Publication number
- CN202362349U CN202362349U CN 201120410169 CN201120410169U CN202362349U CN 202362349 U CN202362349 U CN 202362349U CN 201120410169 CN201120410169 CN 201120410169 CN 201120410169 U CN201120410169 U CN 201120410169U CN 202362349 U CN202362349 U CN 202362349U
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- inverter
- current
- current transformer
- bridge circuit
- current sample
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Abstract
The utility model discloses a lamp current sampling circuit of an inverter, comprising a half-bridge circuit, the inverter and a current transformer. One input end of the inverter is connected with the half-bridge circuit, the other input end is connected with one end of a primary winding of the current transformer, and the other end of the primary winding is connected with the half-bridge circuit; the two output ends of the inverter are high voltage ends respectively, one end of the secondary winding of the current transformer is grounded, and the other end is connected with the anode of a rectifier diode and one end of a sampling resistor separately; the cathode of the rectifier diode is connected with a current sampling end, and the other end of the sampling resistor is grounded. The primary winding of the current transformer of the utility model is connected between the input end of the inverter and the half-bridge circuit, so that the skeleton withstand voltage of the current transformer does not need to be high; moreover, the signal of the current sampling end can reflect the lamp current really, thereby improving the stability of the lamp current.
Description
[technical field]
The utility model relates to fluorescent tube, relates in particular to a kind of inverter lamp tube current sample circuit.
[background technology]
Inverter lamp tube current sample circuit of the prior art; Like Fig. 1; Comprise half-bridge circuit, inverter T1, current transformer T2, two input ends of inverter T1 6,7 are connected with half-bridge circuit, and the output terminal 3 of inverter T1 is high-pressure side+HV1; The output terminal 1 of inverter T1 is connected with an end 4 of the former limit winding of current transformer T2; The other end 3 of former limit winding is high-pressure side+HV2, an end 1 ground connection of the secondary winding of current transformer T2, and the other end 2 of secondary winding meets current sample end Isense through commutation diode D1; The negative electrode of commutation diode D1 meets current sample end Isense; Between the other end 2 of secondary winding and ground, be connected with sampling resistor R2, between an end 1 of end 4 of former limit winding and secondary winding, be connected to distributed capacitance C2, between an end 2 of end 3 of former limit winding and secondary winding, be connected to distributed capacitance C3; And between current sample end Isense and ground, being connected to filtering circuit, this filtering circuit comprises parallel resistor R1 and R3 and capacitor C 1.
Wherein, Half-bridge circuit comprises metal-oxide-semiconductor Q2 and Q1; The drain electrode 2 of metal-oxide-semiconductor Q2 connects the 400V power supply, and the source electrode 3 of metal-oxide-semiconductor Q2 is connected with the drain electrode 2 of metal-oxide-semiconductor Q1, and the grid 1 of metal-oxide-semiconductor Q2 meets drive signal Gate1 and Gate2 respectively with the grid 1 of metal-oxide-semiconductor Q1; The source ground of metal-oxide-semiconductor Q1, and between the source electrode 3 of the drain electrode 2 of metal-oxide-semiconductor Q2 and metal-oxide-semiconductor Q1, be in series with capacitor C 4 and C5; The input end 6 of inverter T1 is connected between the drain electrode 2 of source electrode 3 and metal-oxide-semiconductor Q1 of metal-oxide-semiconductor Q2, and the input end 7 of inverter T1 is connected between capacitor C 4 and the C5.
Because current transformer T2 is connected the high-pressure side and detects lamp current, require the withstand voltage height of wanting of skeleton of current transformer T2, need withstand voltage high framework material (such as LCP) to process; The WV of high-pressure side+HV2 is about 1000Vrms in addition; Frequency of operation is between 50-80KHz; This moment, capacitor C 2 had leakage current with C3; On sampling resistor R2, produce voltage, the signal of current sample end Isense will comprise two signals: 1. lamp current is through the current signal of current transformer T2 induction; 2. pass through the leakage current signal of capacitor C 3; When capacitor C 2, C3, high-pressure side+HV1 changes, all can cause the signal transformation of current sample end Isense like this, this signal just can not truly reflect lamp tube current, can not satisfy needed lamp current requirement.
[summary of the invention]
The utility model provides a kind of inverter lamp tube current sample circuit, and it does not require the withstand voltage height of skeleton of current transformer, and the signal of current sample end can truly reflect lamp tube current, the stability of raising lamp current.
The technical scheme of the utility model is:
A kind of inverter lamp tube current sample circuit; Comprise half-bridge circuit, inverter summation current transformer; It is characterized in that: an input end of inverter is connected with half-bridge circuit; Another input end is connected with an end of the former limit winding of current transformer, and the other end of former limit winding is connected with half-bridge circuit;
Two output terminals of inverter are respectively high-pressure side; One end ground connection of the secondary winding of current transformer; The other end of secondary winding is connected with the anode of commutation diode and an end of sampling resistor respectively, and the negative electrode of commutation diode connects the current sample end, the other end ground connection of sampling resistor.
The inverter lamp tube current sample circuit of the utility model, the former limit winding of current transformer is connected between the input end and half-bridge circuit of inverter, does not need the withstand voltage height of skeleton of current transformer; And can reduce the former limit winding of current transformer and the voltage between the secondary winding; Improve the stability of operation of current transformers; And can reduce the leakage current that is connected the distributed capacitance between former limit winding and the secondary winding; Make the signal of current sample end can truly reflect lamp tube current, improve the stability of lamp current.
[description of drawings]
Fig. 1 is the circuit theory diagrams of inverter lamp tube current sample circuit of the prior art;
Fig. 2 is the circuit theory diagrams of the inverter lamp tube current sample circuit of the utility model.
[embodiment]
Below in conjunction with accompanying drawing the specific embodiment of the utility model is done a detailed elaboration.
Like Fig. 2; The inverter lamp tube current sample circuit of the utility model; Comprise half-bridge circuit, inverter T1 summation current transformer T2; The input end 6 of inverter T1 is connected with half-bridge circuit, and another input end 7 is connected with an end 3 of the former limit winding of current transformer T2, and the other end 4 of former limit winding is connected with half-bridge circuit;
Two output terminals 1,3 of inverter T1 be respectively high-pressure side+HV2 ,+HV1; One end, 1 ground connection of the secondary winding of current transformer T2; The other end 2 of secondary winding is connected with the anode of commutation diode D1 and the end of sampling resistor R2 respectively; The negative electrode of commutation diode D1 meets current sample end Isense, the other end ground connection of sampling resistor R2; Between an end 1 of end 4 of former limit winding and secondary winding, be connected to distributed capacitance C2, between an end 2 of end 3 of former limit winding and secondary winding, be connected to distributed capacitance C3.
During practical implementation; Half-bridge circuit comprises metal-oxide-semiconductor Q1 and Q2; The drain electrode 2 of metal-oxide-semiconductor Q2 connects the 400V power supply, and the source electrode 3 of metal-oxide-semiconductor Q2 is connected with the drain electrode 2 of metal-oxide-semiconductor Q1, and the grid 1 of metal-oxide-semiconductor Q2 meets drive signal Gate1 and Gate2 respectively with the grid 1 of metal-oxide-semiconductor Q1; The source ground of metal-oxide-semiconductor Q1, and between the source electrode 3 of the drain electrode 2 of metal-oxide-semiconductor Q2 and metal-oxide-semiconductor Q1, be in series with capacitor C 4 and C5; The input end 6 of inverter T1 is connected between the drain electrode 2 of source electrode 3 and metal-oxide-semiconductor Q1 of metal-oxide-semiconductor Q2, and an end 4 of the former limit winding of current transformer T2 is connected between capacitor C 4 and the C5.
In addition, the stability for the signal that improves current sample end Isense further also is connected to filtering circuit between current sample end Isense and ground, and like Fig. 2, this filtering circuit can comprise parallel resistor R1, R3 and capacitor C 1.
This shows, the inverter lamp tube current sample circuit of the utility model, the former limit winding of current transformer T2 is connected between the input end and half-bridge circuit of inverter T1, does not need the withstand voltage height of skeleton of current transformer T2; And can reduce the former limit winding of current transformer T2 and the voltage between the secondary winding; Improve the stability of current transformer T2 work; And can reduce the leakage current that is connected the distributed capacitance between former limit winding and the secondary winding; Make the signal of current sample end Isense can truly reflect lamp tube current, improve the stability of lamp current.
Above-described the utility model embodiment does not constitute the qualification to the utility model protection domain.The modification of being done within any spirit and principle at the utility model, be equal to replacement and improvement etc., all should be included within the claim protection domain of the utility model.
Claims (3)
1. inverter lamp tube current sample circuit; Comprise half-bridge circuit, inverter summation current transformer; It is characterized in that: an input end of inverter is connected with half-bridge circuit; Another input end is connected with an end of the former limit winding of current transformer, and the other end of former limit winding is connected with half-bridge circuit;
Two output terminals of inverter are respectively high-pressure side; One end ground connection of the secondary winding of current transformer; The other end of secondary winding is connected with the anode of commutation diode and an end of sampling resistor respectively, and the negative electrode of commutation diode connects the current sample end, the other end ground connection of sampling resistor.
2. inverter lamp tube current sample circuit according to claim 1 is characterized in that: between current sample end and ground, also be connected with filtering circuit.
3. inverter lamp tube current sample circuit according to claim 2 is characterized in that: said filtering circuit comprises two resistance and the electric capacity of parallel connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120410169 CN202362349U (en) | 2011-10-25 | 2011-10-25 | Lamp current sampling circuit of inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201120410169 CN202362349U (en) | 2011-10-25 | 2011-10-25 | Lamp current sampling circuit of inverter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202362349U true CN202362349U (en) | 2012-08-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201120410169 Expired - Fee Related CN202362349U (en) | 2011-10-25 | 2011-10-25 | Lamp current sampling circuit of inverter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202362349U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426288A (en) * | 2011-10-25 | 2012-04-25 | 深圳麦格米特电气股份有限公司 | Inverter tube current sampling circuit |
| CN103353546A (en) * | 2013-05-31 | 2013-10-16 | 宁波高新区日新科技有限公司 | Overload detection circuit of inverter by using on-resistance of MOSFET |
-
2011
- 2011-10-25 CN CN 201120410169 patent/CN202362349U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102426288A (en) * | 2011-10-25 | 2012-04-25 | 深圳麦格米特电气股份有限公司 | Inverter tube current sampling circuit |
| CN103353546A (en) * | 2013-05-31 | 2013-10-16 | 宁波高新区日新科技有限公司 | Overload detection circuit of inverter by using on-resistance of MOSFET |
| CN103353546B (en) * | 2013-05-31 | 2015-07-08 | 宁波高新区日新科技有限公司 | Overload detection circuit of inverter by using on-resistance of MOSFET |
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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: 20120801 Termination date: 20201025 |