CN201956897U - Logical link control (LLC) topology circuit output overcurrent constant current protection circuit for switching power supply - Google Patents
Logical link control (LLC) topology circuit output overcurrent constant current protection circuit for switching power supply Download PDFInfo
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- CN201956897U CN201956897U CN2010205340581U CN201020534058U CN201956897U CN 201956897 U CN201956897 U CN 201956897U CN 2010205340581 U CN2010205340581 U CN 2010205340581U CN 201020534058 U CN201020534058 U CN 201020534058U CN 201956897 U CN201956897 U CN 201956897U
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Abstract
The utility model discloses a logical link control (LLC) topology circuit output overcurrent protection circuit for a switching power supply. The constant current protection circuit consists of a voltage sampling circuit, a voltage stabilization error amplifier and an isolating circuit. The voltage stabilization error amplifier adopts an operational amplifier. After being improved, the protection circuit is provided with an overcurrent protection circuit. The overcurrent protection circuit consists of a current sampling circuit, a second operational amplifier and a driving triode, wherein the current sampling circuit consists of a second resistor and a third resistor; the collector of the triode is connected with the cathode end of a light emitting diode of a photoelectric coupler; and the output of the photoelectric coupler is connected to the control chip regulation end V-FB of the switching power supply. By the protection circuit, in output overcurrent, an LLC works in an intermittent mode, output current can be ensured to be constant, and the current stress requirement and output short-circuit requirement of a power device can be completely met.
Description
Technical field
The utility model relates to a kind of output overcurrent protective circuit of LLC topological circuit, belongs to power technique fields.
Background technology
Along with developing rapidly of switch power technology, high-power, high efficiency, high power density have become a kind of development trend of Switching Power Supply.Improving switching frequency is a kind of effective solution, but the rising of switching frequency has brought the excessive problem of switching tube loss, and this is that conventional transducers is insurmountable, and the LLC controlled resonant converter then can address this problem preferably.
LLC series resonance translation circuit can either satisfy the requirement of high frequencyization as a kind of special topological circuit, can reach higher conversion efficiency again, but since the LLC resonant circuit be operated in 50% decide pulsewidth, the adjustment operating frequency realize voltage stabilizing.When output overcurrent even short circuit, operating frequency rises to maximum setpoint frequency, because of its pulsewidth still is 50%, so also have certain power output ability, output current can increase with output voltage decline when degree of depth overcurrent or short circuit, short circuit current tends to exceed set 200% of flow point, and the current stress of power tube will be very big, might damage power device.For the current stress that reduces power tube and satisfy the output short circuit protection requirement, will take to limit size of current during output overcurrent.The overcurrent protection mode of general output is to adopt the shunt sampling; current signal is converted into voltage signal; after amplifying, send operational amplifier; compare with benchmark; operational amplifier output drags down the benchmark of voltage stabilizing departure amplifier by diode-isolated; thereby output voltage is descended, reach the overcurrent protection purpose.Intermittent mode is not adopted in LLC work, if the LLC discontinuous operation, output ripple can become greatly, often can not meet the demands.
The utility model content
The purpose of this utility model is to provide a kind of LLC topological circuit output overcurrent constant current protective circuit of Switching Power Supply of easy to use and dependable performance.
The alleged problem of the utility model realizes with following technical proposals:
A kind of LLC topological circuit output overcurrent constant current protective circuit of Switching Power Supply; it is by voltage sampling circuit; the voltage stabilizing error amplifier; buffer circuit is formed; described voltage stabilizing error amplifier adopts transport and placing device to form; described voltage sampling circuit is made up of the 4th resistance and the 5th resistance; be connected on the output voltage VO UT after the described two resistance serial connection; its serial connection point is connected to the inverting input of first transport and placing device; the in-phase input end of transport and placing device is connected on the reference voltage S-5V; the output of first transport and placing device is connected in buffer circuit through first diode; buffer circuit adopts photoelectrical coupler; the output of photoelectrical coupler is connected to the control chip adjustment end V-FB of Switching Power Supply; after the improvement; set up current foldback circuit; described current foldback circuit is by current sampling circuit; second operational amplifier and driving triode are formed; described current sampling circuit is made up of second resistance and the 3rd resistance; be connected on the sample rate current end I-OUT after the two resistance serial connection; its serial connection point is connected in the in-phase input end of second transport and placing device; inverting input is connected on the reference voltage S-5V; the output of second transport and placing device connects the base stage that drives triode through second diode, and the collector electrode of triode is connected to the cathode terminal of the light-emitting diode of photoelectrical coupler.
The LLC topological circuit output overcurrent constant current protective circuit of above-mentioned Switching Power Supply; on second transport and placing device, set up negative feedback network; described negative feedback network is formed R, a C, C negative-feedback circuit by the 8th resistance, second electric capacity and the 3rd electric capacity, and described negative-feedback circuit is connected between the output and inverting input of second operational amplifier.
The utility model can guarantee that output current is constant, and when output short-circuit, short circuit current can increase to some extent, but can not surpass 120% of current setpoint.Output voltage steadily descends in the whole overcurrent process, and output current is more constant, and the current stress that can satisfy power device requires and the output short-circuit requirement.
The protective circuit that the utility model provides is functional and reliable, even export long-term short circuit, can satisfy the requirement of current stress and thermal stress.Circuit is fairly simple, is easy to realize.
Description of drawings
The utility model is described in further detail below in conjunction with accompanying drawing.
Fig. 1 is an electrical schematic diagram of the present utility model.
Each label list is shown among the figure:
OUT+: output voltage; I_OUT: sample rate current end; GND: ground; Vcc: accessory power supply; S_5V: reference voltage; V_FB: the control chip adjustment end of Switching Power Supply; D1: first diode; D2: second diode; R1～R13: resistance; C1～C6: electric capacity; Q: triode.
Embodiment
Referring to Fig. 1, the utility model adopts operational amplifier, resistance, electric capacity, diode, driving triode to form current foldback circuit; The output services of control chip are at intermittent mode during the LLC overcurrent protection.The principle that this circuit is finished overcurrent constant current protection is as follows:
When the voltage of in-phase input end end 5 pin of second transport and placing device during greater than end of oppisite phase 4 pin voltages, because negative feedback is arranged, the output 7 pin voltage linears of second operational amplifier raise, and drive the linear conducting of triode Q by the second diode D2 and current-limiting resistance R24.The cathode voltage of light-emitting diode is dragged down among the photoelectrical coupler OT1, the light-emitting diodes pipeline conducting of OT1, the linear conducting of the triode of OT1, its output signal can be adjusted the FREQUENCY CONTROL pin of the control IC chip of Switching Power Supply, operating frequency is linear to raise until the highest set-point, and output voltage is linear to descend.When adding heavy load until short circuit again, LLC enters the discontinuous operation pattern, and output voltage continue to descend until near 0V, and discontinuous operation has guaranteed that output current is constant.When output short-circuit, short circuit current can increase to some extent, but can not surpass 120% of current setpoint.The current stress that like this, just can satisfy power device requires and the output short-circuit requirement.
The output of operational amplifier and end of oppisite phase add negative feedback network in the utility model, can guarantee that the output overcurrent state is steady.
Claims (2)
1. the LLC topological circuit output overcurrent constant current protective circuit of a Switching Power Supply; it is by voltage sampling circuit; the voltage stabilizing error amplifier; buffer circuit is formed; described voltage stabilizing error amplifier adopts transport and placing device to form; described voltage sampling circuit is made up of the 4th resistance R 4 and the 5th resistance R 5; be connected on the output voltage VO UT after the described two resistance serial connection; its serial connection point is connected to the inverting input of the first transport and placing device U1; the in-phase input end of transport and placing device is connected on the reference voltage S-5V; the output of first transport and placing device is connected in buffer circuit through the first diode D1; buffer circuit adopts photoelectrical coupler OT1; the output of photoelectrical coupler is connected to the control chip adjustment end V-FB of Switching Power Supply; it is characterized in that; set up current foldback circuit; described current foldback circuit is by current sampling circuit; second operational amplifier (U2) and driving triode Q form; described current sampling circuit is made up of second resistance R 2 and the 3rd resistance R 3; be connected on the sample rate current end I-OUT after the two resistance serial connection; its serial connection point is connected in the in-phase input end of second transport and placing device; inverting input is connected on the reference voltage S-5V; the output of second transport and placing device connects the base stage that drives triode through the second diode D2, and the collector electrode of triode is connected to the cathode terminal of the light-emitting diode of photoelectrical coupler.
2. the LLC topological circuit output overcurrent constant current protective circuit of Switching Power Supply according to claim 1; it is characterized in that; on second transport and placing device, set up negative feedback network; described negative feedback network is formed R, a C, C negative-feedback circuit by the 8th resistance (R8), second electric capacity (C2) with the 3rd electric capacity (C3), and described negative-feedback circuit is connected between the output and inverting input of second operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205340581U CN201956897U (en) | 2010-09-19 | 2010-09-19 | Logical link control (LLC) topology circuit output overcurrent constant current protection circuit for switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205340581U CN201956897U (en) | 2010-09-19 | 2010-09-19 | Logical link control (LLC) topology circuit output overcurrent constant current protection circuit for switching power supply |
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| Publication Number | Publication Date |
|---|---|
| CN201956897U true CN201956897U (en) | 2011-08-31 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2010205340581U Expired - Fee Related CN201956897U (en) | 2010-09-19 | 2010-09-19 | Logical link control (LLC) topology circuit output overcurrent constant current protection circuit for switching power supply |
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| CN (1) | CN201956897U (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102548158A (en) * | 2012-03-28 | 2012-07-04 | 无锡安特源科技有限公司 | Light load control structure of power supply using logic link control (LLC) topology |
| CN103187710A (en) * | 2012-12-10 | 2013-07-03 | 江苏嘉钰新能源技术有限公司 | Current-limit and over-current double current loop protection circuit |
| CN103337948A (en) * | 2012-12-10 | 2013-10-02 | 江苏嘉钰新能源技术有限公司 | Double current loop circuit for controlling pulse width of output voltage |
| CN103872912A (en) * | 2012-12-13 | 2014-06-18 | 北京普源精电科技有限公司 | Linear power supply |
| CN104935778A (en) * | 2014-11-28 | 2015-09-23 | 成都冠深科技有限公司 | Coupled reverse current source graph processing system based on constant-current protection |
| CN106300917A (en) * | 2016-10-09 | 2017-01-04 | 深圳市钜能科技有限公司 | Negative-feedback circuit |
| CN106793230A (en) * | 2017-01-25 | 2017-05-31 | 苏州振湖电炉有限公司 | The current foldback circuit of induction furnace induction coil |
| CN108631566A (en) * | 2017-03-22 | 2018-10-09 | 圣邦微电子（北京）股份有限公司 | The circuit of protection is split to power input output |
| CN110649800A (en) * | 2019-10-25 | 2020-01-03 | 天津航空机电有限公司 | High-precision current limiting circuit |
-
2010
- 2010-09-19 CN CN2010205340581U patent/CN201956897U/en not_active Expired - Fee Related
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102548158A (en) * | 2012-03-28 | 2012-07-04 | 无锡安特源科技有限公司 | Light load control structure of power supply using logic link control (LLC) topology |
| CN103187710A (en) * | 2012-12-10 | 2013-07-03 | 江苏嘉钰新能源技术有限公司 | Current-limit and over-current double current loop protection circuit |
| CN103337948A (en) * | 2012-12-10 | 2013-10-02 | 江苏嘉钰新能源技术有限公司 | Double current loop circuit for controlling pulse width of output voltage |
| CN103187710B (en) * | 2012-12-10 | 2015-07-08 | 江苏嘉钰新能源技术有限公司 | Current-limit and over-current double current loop protection circuit |
| CN103872912B (en) * | 2012-12-13 | 2018-02-23 | 北京普源精电科技有限公司 | A kind of linear power supply |
| CN103872912A (en) * | 2012-12-13 | 2014-06-18 | 北京普源精电科技有限公司 | Linear power supply |
| CN104935778A (en) * | 2014-11-28 | 2015-09-23 | 成都冠深科技有限公司 | Coupled reverse current source graph processing system based on constant-current protection |
| CN106300917A (en) * | 2016-10-09 | 2017-01-04 | 深圳市钜能科技有限公司 | Negative-feedback circuit |
| CN106793230A (en) * | 2017-01-25 | 2017-05-31 | 苏州振湖电炉有限公司 | The current foldback circuit of induction furnace induction coil |
| CN106793230B (en) * | 2017-01-25 | 2023-02-07 | 苏州振湖电炉有限公司 | Overcurrent protection circuit of induction furnace induction coil |
| CN108631566A (en) * | 2017-03-22 | 2018-10-09 | 圣邦微电子（北京）股份有限公司 | The circuit of protection is split to power input output |
| CN108631566B (en) * | 2017-03-22 | 2024-04-16 | 圣邦微电子（北京）股份有限公司 | Circuit for splitting and protecting power input and output |
| CN110649800A (en) * | 2019-10-25 | 2020-01-03 | 天津航空机电有限公司 | High-precision current limiting circuit |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C41 | Transfer of patent application or patent right or utility model | ||
| C56 | Change in the name or address of the patentee | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 050035 No. 56, 3 Kunlun street, Shijiazhuang Development Zone, Hebei, China Patentee after: Shijiazhuang Guoyao Eletronic Co.,Ltd. Patentee after: SHENZHEN GYE ELECTRONIC TECHNOLOGY Co.,Ltd. Address before: 050035 No. 56, 3 Kunlun street, Shijiazhuang Development Zone, Hebei, China Patentee before: Shijiazhuang Guoyao Eletronic Co.,Ltd. Patentee before: Shenzhen Guoyao Electronic Technology Co.,Ltd. |
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| TR01 | Transfer of patent right |
Effective date of registration: 20151218 Address after: Longgang District of Shenzhen City, Guangdong province 518129 Buji Bantian Jihua Road, Liuzhou Choi industrial city 10 Building 6 layer Patentee after: SHENZHEN GYE ELECTRONIC TECHNOLOGY Co.,Ltd. Address before: 050035 No. 56, 3 Kunlun street, Shijiazhuang Development Zone, Hebei, China Patentee before: Shijiazhuang Guoyao Eletronic Co.,Ltd. Patentee before: SHENZHEN GYE ELECTRONIC TECHNOLOGY Co.,Ltd. |
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| 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: 20110831 Termination date: 20180919 |