CN201639500U - Constant output current control circuit for flyback switching power supply - Google Patents
Constant output current control circuit for flyback switching power supply Download PDFInfo
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- CN201639500U CN201639500U CN2010201610346U CN201020161034U CN201639500U CN 201639500 U CN201639500 U CN 201639500U CN 2010201610346 U CN2010201610346 U CN 2010201610346U CN 201020161034 U CN201020161034 U CN 201020161034U CN 201639500 U CN201639500 U CN 201639500U
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- control circuit
- output current
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Abstract
The utility model discloses a constant output current control circuit for a flyback switching power supply and a control method. The constant output current control circuit comprises a primary coil, a secondary coil, an auxiliary coil, a control circuit, a signal processing circuit connected with the control circuit, a switching tube and a current sampling resistor. The control end of the switching tube receives the signal of the control circuit, one end of the switching tube is connected with the primary coil, the other end thereof is connected with the current sampling resistor in series and is connected to the ground and the switching tube outputs a current signal to the control circuit. The auxiliary coil outputs a signal to the signal processing circuit and the control circuit. The utility model has the advantages that the output control is completed through the primary circuit of the transformer without requiring the participation of the secondary circuit, the output current is controlled to be constant or is limited through the signal of the primary circuit when the switching power supply system works, the structure is simpler, the cost is low and the efficiency is high.
Description
Technical field
The utility model relates to the switch power technology field in the power electronics, relates in particular to a kind of constant control circuit of output current that is used for inverse-excitation type switch power-supply.
Background technology
Our general said Switching Power Supply is meant the converter (AC-DCADAPTOR) from the high-voltage alternating to the low-voltage direct; the work of switch power supply system is controlled by control section; the content of control comprises the switch control of switching tube, the voltage of output and Current Control, various protection controls etc.Wherein the control of output is comprised the control of output voltage and output current, wherein the control to output current generally has constant current output control, use as LED, current limliting output control mode is also arranged, both exported maximum current limit, constant voltage output under the normal condition, electric current is by the size decision of load, but arrive the to a certain degree maximum current of restriction output greatly when load, as the application of battery charger, these two kinds of outputs all need the output current of maximum is controlled, general control method has two kinds, as Fig. 1, the systematic sampling output current signal amplifies and feeds back to the control section of input stage to current error signal, by the pulse that changes switch the output of system is controlled, make output current keep constant, in this mode, general Switching Power Supply output stage and input stage are isolated mutually by transformer, this method need feed back to input stage to the Signal Spacing of output stage, need to isolate transmission, circuit complexity, cost height; Planting controlling schemes commonly used in addition and see Fig. 2, is exactly the element of series connection Current limited Control on the loop of output stage, makes the electric current on the loop be no more than predetermined electric current.Restricted portion is serially connected in the loop of output in this scheme, the certain pressure drop of need of work loss of this partial circuit, it is exactly the energy of loss that operating current is taken advantage of in the pressure drop of this part loss, the operating efficiency of meeting reduction system, increase the heating of power-supply system, increase the complexity of circuit structure simultaneously and increase the element direct cost.All need output stage to participate in feedback or control in these two kinds of schemes.
Summary of the invention
The purpose of this utility model is to overcome the defective of prior art and a kind of constant control circuit of output current that is used for inverse-excitation type switch power-supply is provided, its output control is finished by the elementary of transformer, do not need secondary circuit to participate in, elementary signal is controlled the constant or current limliting of output current when utilizing switch power supply system work.
The technical scheme that realizes above-mentioned purpose is: a kind of constant control circuit of output current that is used for inverse-excitation type switch power-supply, comprise a transformer, this transformer comprises primary coil T1 and secondary coil T2, wherein, the described constant control circuit of output current that is used for inverse-excitation type switch power-supply comprises a control circuit, the signal processing circuit that links to each other with this control circuit, a switching tube and the current sampling resistor of the back ground connection of connecting with this switching tube, described transformer also comprises an ancillary coil T3 who links to each other with described signal processing circuit, wherein:
The signal that described switch controlled termination is received control circuit with the conducting of control switch whether, an end of switching tube links to each other with described primary coil T1, the other end is connected described current sampling resistor to ground, and output current signal is to control circuit;
The end ground connection of the same name of described ancillary coil T3, the different name end outputs signal to described signal processing circuit and control circuit respectively.
The above-mentioned constant control circuit of the output current that is used for inverse-excitation type switch power-supply, wherein, the different name end of described ancillary coil T3 links to each other with described control circuit with to control circuit power supply by one second diode D2, and by this second diode D2 one the 3rd capacitor C 3 ground connection afterwards of connecting.
The above-mentioned constant control circuit of the output current that is used for inverse-excitation type switch power-supply, wherein, the end of the same name of described primary coil T1 is by one first capacitor C, 1 ground connection, the different name end of described secondary coil T2 is in series with one first diode D1, ground connection after this first diode D1 connects with one second capacitor C 2, the end ground connection of the same name of described secondary coil T2.
The above-mentioned constant control circuit of the output current that is used for inverse-excitation type switch power-supply, wherein, the non-same ground of the earth terminal of the earth terminal of described first capacitor C 1 and second capacitor C 2, electric going up mutually isolated.
The beneficial effects of the utility model are: the utility model can be used among the design of switching power source chip, can improve the operating efficiency of system, reduce volume, can solve application because of volume requirement, the heat radiation requirement, present product can be used and transform to the design bottleneck that cost requirement etc. bring, can promote the development of new product, as the application of LED illumination, charger for mobile phone etc.
Description of drawings
Fig. 1 is the Switching Power Supply structural representation of a kind of constant current output of the prior art;
Fig. 2 is the Switching Power Supply structural representation of a kind of current limliting output of the prior art;
Fig. 3 is a kind of structural representation that is used for the constant control circuit of output current of inverse-excitation type switch power-supply of the present utility model.
Embodiment
The utility model is described in further detail below in conjunction with accompanying drawing.
See also Fig. 3, there is shown a kind of constant control circuit of output current that is used for inverse-excitation type switch power-supply of the present utility model, comprise a transformer TX2, this transformer TX2 comprises primary coil T1 and secondary coil T2, the current sampling resistor Ris of the signal processing circuit 2 that the constant control circuit of output current that is used for inverse-excitation type switch power-supply comprises a control circuit 1, link to each other with this control circuit 1, a switching tube SW1 and the back ground connection of connecting with this switching tube SW1, transformer TX2 also comprises an ancillary coil T3 who links to each other with signal processing circuit 2, wherein:
The signal Driver of switching tube SW1 control end reception control circuit 1 with the conducting of control switch whether, the end of switching tube SW1 links to each other with primary coil T1, other end series current sample resistance Ris is to ground, and output current signal Isw gives control circuit 1;
Ancillary coil T3 provides power supply for control circuit 1 work, its end ground connection of the same name, the different name end outputs signal to signal processing circuit 2 and control circuit 1 respectively, be in series with one second diode D2 between its different name end and the control circuit 1 giving control circuit 1 power supply, and by this second diode D2 one the 3rd capacitor C, 3 back ground connection of connecting;
The end of the same name of primary coil T1 is by one first capacitor C, 1 ground connection, the different name end of secondary coil T2 is in series with one first diode D1, ground connection after this first diode D1 connects with one second capacitor C 2, the end ground connection of the same name of secondary coil T2, the non-same ground of the earth terminal of the earth terminal of first capacitor C 1 and second capacitor C 2, electric going up mutually isolated.
The utility model utilizes the signal of ancillary coil T3 in the transformer TX2 work to control the constant current or the current limliting of output.The primary coil T1 of transformer TX2 and ancillary coil T3 work on the ground at same reference potential in this scheme, do not need the isolation between electric each other.Elementary control circuit 1 can be directly be fused to and just control can be finished.Solved the defective that power supply architecture of the prior art brings.
Above embodiment is only for the usefulness that the utility model is described, but not to restriction of the present utility model, person skilled in the relevant technique, under the situation that does not break away from spirit and scope of the present utility model, can also make various conversion or modification, therefore all technical schemes that are equal to also should belong to category of the present utility model, should be limited by each claim.
Claims (4)
1. constant control circuit of output current that is used for inverse-excitation type switch power-supply, comprise a transformer, this transformer comprises primary coil T1 and secondary coil T2, it is characterized in that, the described constant control circuit of output current that is used for inverse-excitation type switch power-supply comprises a control circuit, the signal processing circuit that links to each other with this control circuit, a switching tube and the current sampling resistor of the back ground connection of connecting with this switching tube, described transformer also comprises an ancillary coil T3 who links to each other with described signal processing circuit, wherein:
The signal that described switch controlled termination is received control circuit with the conducting of control switch whether, an end of switching tube links to each other with described primary coil T1, the other end is connected described current sampling resistor to ground, and output current signal is to control circuit;
The end ground connection of the same name of described ancillary coil T3, the different name end outputs signal to described signal processing circuit and control circuit respectively.
2. the constant control circuit of output current that is used for inverse-excitation type switch power-supply according to claim 1, it is characterized in that, the different name end of described ancillary coil T3 links to each other with described control circuit with to control circuit power supply by one second diode D2, and by this second diode D2 one the 3rd capacitor C 3 ground connection afterwards of connecting.
3. the constant control circuit of output current that is used for inverse-excitation type switch power-supply according to claim 1 and 2, it is characterized in that, the end of the same name of described primary coil T1 is by one first capacitor C, 1 ground connection, the different name end of described secondary coil T2 is in series with one first diode D1, ground connection after this first diode D1 connects with one second capacitor C 2, the end ground connection of the same name of described secondary coil T2.
4. the constant control circuit of output current that is used for inverse-excitation type switch power-supply according to claim 3 is characterized in that, the non-same ground of the earth terminal of the earth terminal of described first capacitor C 1 and second capacitor C 2, and electric going up mutually isolated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201610346U CN201639500U (en) | 2010-04-16 | 2010-04-16 | Constant output current control circuit for flyback switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010201610346U CN201639500U (en) | 2010-04-16 | 2010-04-16 | Constant output current control circuit for flyback switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201639500U true CN201639500U (en) | 2010-11-17 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010201610346U Expired - Lifetime CN201639500U (en) | 2010-04-16 | 2010-04-16 | Constant output current control circuit for flyback switching power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201639500U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814848A (en) * | 2010-04-16 | 2010-08-25 | 上海宣研电子科技有限公司 | Constant output current control circuit and control method for fly-back switch power supply |
-
2010
- 2010-04-16 CN CN2010201610346U patent/CN201639500U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101814848A (en) * | 2010-04-16 | 2010-08-25 | 上海宣研电子科技有限公司 | Constant output current control circuit and control method for fly-back switch power supply |
| CN101814848B (en) * | 2010-04-16 | 2012-02-29 | 深圳市力生美半导体器件有限公司 | Constant output current control circuit and control method for fly-back switch power supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: SHENZHEN LIISEMI SEMICONDUCTOR DEVICES CO., LTD. Free format text: FORMER OWNER: SHANGHAI XUANYAN ELECTRONIC TECHNOLOGY CO., LTD. Effective date: 20110715 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: 200240 NO. 150, LANE 555, JINPING ROAD, MINHANG DISTRICT, SHANGHAI TO: 518000 NO. 2, JINLONG AVENUE, BAOLONG COMMUNITY, LONGGANG SUBDISTRICT, LONGGANG DISTRICT, SHENZHEN CITY, GUANGDONG PROVINCE |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20110715 Address after: No. 2 Longgang District of Shenzhen City, Guangdong province 518000 Longgang Street Baolong community Jinlong Avenue Patentee after: Shenzhen Lishengmei Semiconductor Deveces Co., Ltd. Address before: 200240, No. 555, Lane 150, Jinping Road, Shanghai, Minhang District Patentee before: Shanghai Xuanyan Electronic Science and Technology Co., Ltd. |
|
| C56 | Change in the name or address of the patentee | ||
| CP03 | Change of name, title or address |
Address after: 518000, Shenzhen, Guangdong Province, Nanshan District science and technology road, 1, SED science and technology building on the south side of the 10 floor, block A Patentee after: SHENZHEN LII SEMICONDUCTOR CO., LTD. Address before: No. 2 Longgang District of Shenzhen City, Guangdong province 518000 Longgang Street Baolong community Jinlong Avenue Patentee before: Shenzhen Lishengmei Semiconductor Deveces Co., Ltd. |
|
| CX01 | Expiry of patent term |
Granted publication date: 20101117 |
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| CX01 | Expiry of patent term |