CN204761573U - Novel LED TV flyback converter - Google Patents
Novel LED TV flyback converter Download PDFInfo
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- CN204761573U CN204761573U CN201520473661.6U CN201520473661U CN204761573U CN 204761573 U CN204761573 U CN 204761573U CN 201520473661 U CN201520473661 U CN 201520473661U CN 204761573 U CN204761573 U CN 204761573U
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Abstract
The utility model provides a LED TV flyback converter, includes chip U1, triode Q1, field effect transistor Q2 and transformer T1, chip U1's 1 foot ground connection, chip U1's 2 feet connect optical coupler PC's 4 feet, this optical coupler PC's 3 foot ground connection, and this optical coupler PC is still parallelly connected to have an electric capacity C1, chip U1's 3 feet connect ground connection behind the resistance R1, chip U1's 4 feet connect resistance R7 to connect field effect transistor Q2's source electrode all the way, and another way connects ground connection behind the RC parallel circuit who comprises resistance R4 and electric capacity C2. Through foretell circuit design, not only efficiency is higher but also the input voltage range broad.
Description
Technical field
The utility model relates to TV technology, particularly a kind of New LED TV circuit of reversed excitation.
Background technology
LED television in the past comprises TV motherboard, liquid crystal display screen, current rectifying and wave filtering circuit, pfc circuit, circuit of reversed excitation and LED drive circuit, and liquid crystal display screen comprises LED backlight.Wherein current rectifying and wave filtering circuit receives to exchange and inputs and carry out rectifying and wave-filtering to provide the first direct voltage.Pfc circuit connects current rectifying and wave filtering circuit to receive the first direct voltage and to provide the second direct voltage after carrying out Active PFC.Circuit of reversed excitation receives the second direct voltage and exports the 3rd direct voltage and the 4th direct voltage, TV motherboard and LED drive circuit receive the 3rd direct voltage respectively as operating voltage, and LED drive circuit receives the 4th direct voltage and provides supply voltage to LED backlight whereby.
Circuit of reversed excitation in the past mainly comprises flyback controller, flyback transformer, mains switch, detection resistance, the first output diode, the second output diode and feedback circuit; The former limit winding of flyback transformer receive the second direct voltage and sequentially by mains switch and detect grounding through resistance; Node between mains switch from detection resistance and the control end of mains switch are electrically connected to the different pins of flyback controller respectively; One end of the vice-side winding of flyback transformer exports the 4th direct voltage by the first output diode, and the other end exports the 3rd direct voltage by the second output diode; Feedback circuit is electrically connected between the 3rd direct voltage and the feedback pin of flyback controller.Above-mentioned feedback circuit such as has feedback input end and start/Opportunity awaiting control for linear end and mainly comprises optical coupler, error amplifier, control switch, diode and the first to the 6th resistance; An output of optical coupler is electrically connected to the feedback pin of flyback controller and another output head grounding, an input of optical coupler is electrically connected to this feedback input end by the first resistance, and another input is electrically connected to feedback input end by the second resistance and by error amplifier ground connection; 3rd resistance and the 5th resistance are serially connected with between feedback input end and ground, and the node between the 3rd resistance and the 5th resistance is electrically connected to the control end of error amplifier; One end of 4th resistance is electrically connected to feedback input end, and the other end is by control switch ground connection and sequentially by diode and the 6th grounding through resistance, and the node between diode and the 6th resistance is electrically connected to the control end of error amplifier; The control end of control switch is electrically connected to start/Opportunity awaiting control for linear end, and feedback input end is electrically connected to the 3rd direct voltage.There is the problems such as efficiency is lower, input voltage range is narrower in the circuit of reversed excitation of above-mentioned design.
Therefore, prior art needs to be improved and improves.
Summary of the invention
For the above-mentioned problems in the prior art, the purpose of this utility model is to provide that a kind of efficiency is higher, the circuit of reversed excitation of wide input voltage range.
For achieving the above object, the technical scheme that the utility model adopts is:
A kind of New LED TV circuit of reversed excitation, comprises chip U1, triode Q1, field effect transistor Q2 and transformer T1, the 1 pin ground connection of described chip U1; 2 pin of described chip U1 connect 4 pin of optical coupler PC, the 3 pin ground connection of this optical coupler PC, and this optical coupler PC is also parallel with an electric capacity C1; 3 pin of described chip U1 connect ground connection after a resistance R1; The 4 pin one road connecting resistance R7 of described chip U1 connect the source electrode of field effect transistor Q2, and another road connects ground connection after the RC parallel circuits be made up of resistance R4 and electric capacity C2; 5 pin one tunnels of described chip U1 meet power supply VCC, connect the first power end after another road series resistor R2 and resistance R3, and the 3rd tunnel connects ground connection after an electric capacity C3, and the 4th tunnel connects the positive pole of polar capacitor C7, the minus earth of this electric capacity C7; Connect the base stage of triode Q1 after the 6 pin one road connecting resistance R6 of described chip U1, after the connecting resistance R5 of another road, connect the emitter of triode Q1; The emitter of this triode Q1 connects the grid of field effect transistor Q2; The source electrode of field effect transistor Q2 is connect after the collector electrode connecting resistance R9 of described triode Q1; Be connected to resistance R10 between the grid of described field effect transistor Q2 and source electrode, between source electrode and drain electrode, be connected to electric capacity C6, ground connection after the source electrode connecting resistance R11 of this field effect transistor Q2; The drain electrode of described field effect transistor Q2, one tunnel connects the anode of diode D1, another road connects the positive pole of rectifier diode D7, the negative pole of this rectifier diode D7 connects transformer T1 input 5 pin, second source end is connect after the negative electrode one road connecting resistance R12 of this diode D1, second source end is connect, the positive pole of this second source termination polar capacitor C5, the minus earth of this polar capacitor C5 after another road serial capacitance C4 and resistance R14 in parallel and resistance R13; Input 4 pin of described transformer connects second source end; Input 1 pin of described transformer T1 connects diode D2 in parallel in the same way and the anode of diode D7, and the negative electrode of this diode D2 and diode D7 connects the positive pole of polar capacitor C7; The input 2 pin ground connection of described transformer T1; Power supply is connect after the output 12 pin one road serial capacitance C10 of described transformer T1 and resistance R18,19,20,21 in parallel, another road connects the anode of diode D3 and D4 in parallel in the same way, negative electrode one tunnel of those diodes D3 and D4 connects power supply, another takes turns the positive pole meeting polar capacitor C11 and C12 in parallel in the same way, the minus earth of those polar capacitors C11 and C12, those polar capacitors C11 and C12 is also parallel with a resistance R22; Output 8 pin of described transformer T1 connects with 7 pin, this output 10 pin connects the anode of diode D5 and D6 in parallel in the same way, the negative electrode of those diodes D5 and D6 connects the positive pole of polar capacitor C14 and C15 in parallel in the same way, the minus earth of this polar capacitor C14 and C15, the negative electrode of described diode D5 and D6 also connects power supply, the output 7 pin ground connection of described transformer.
Compared with prior art, the beneficial effects of the utility model are: by above-mentioned circuit design, not only efficiency is higher, and input voltage range is wider.
Accompanying drawing illustrates '
Accompanying drawing 1 is circuit theory diagrams of the present utility model.
Embodiment
The utility model is described in further detail to provide embodiment below in conjunction with accompanying drawing:
Refer to Fig. 1, a kind of New LED TV of the utility model circuit of reversed excitation, comprises chip U1, triode Q1, field effect transistor Q2 and transformer T1, the 1 pin ground connection of described chip U1; 2 pin of described chip U1 connect 4 pin of optical coupler PC, the 3 pin ground connection of this optical coupler PC, and this optical coupler PC is also parallel with an electric capacity C1; 3 pin of described chip U1 connect ground connection after a resistance R1; The 4 pin one road connecting resistance R7 of described chip U1 connect the source electrode of field effect transistor Q2, and another road connects ground connection after the RC parallel circuits be made up of resistance R4 and electric capacity C2; 5 pin one tunnels of described chip U1 meet power supply VCC, connect the first power end after another road series resistor R2 and resistance R3, and the 3rd tunnel connects ground connection after an electric capacity C3, and the 4th tunnel connects the positive pole of polar capacitor C7, the minus earth of this electric capacity C7; Connect the base stage of triode Q1 after the 6 pin one road connecting resistance R6 of described chip U1, after the connecting resistance R5 of another road, connect the emitter of triode Q1; The emitter of this triode Q1 connects the grid of field effect transistor Q2; The source electrode of field effect transistor Q2 is connect after the collector electrode connecting resistance R9 of described triode Q1; Be connected to resistance R10 between the grid of described field effect transistor Q2 and source electrode, between source electrode and drain electrode, be connected to electric capacity C6, ground connection after the source electrode connecting resistance R11 of this field effect transistor Q2; The drain electrode of described field effect transistor Q2, one tunnel connects the anode of diode D1, another road connects the positive pole of rectifier diode D7, the negative pole of this rectifier diode D7 connects transformer T1 input 5 pin, second source end is connect after the negative electrode one road connecting resistance R12 of this diode D1, second source end is connect, the positive pole of this second source termination polar capacitor C5, the minus earth of this polar capacitor C5 after another road serial capacitance C4 and resistance R14 in parallel and resistance R13; Input 4 pin of described transformer connects second source end; Input 1 pin of described transformer T1 connects diode D2 in parallel in the same way and the anode of diode D7, and the negative electrode of this diode D2 and diode D7 connects the positive pole of polar capacitor C7; The input 2 pin ground connection of described transformer T1; Power supply is connect after the output 12 pin one road serial capacitance C10 of described transformer T1 and resistance R18,19,20,21 in parallel, another road connects the anode of diode D3 and D4 in parallel in the same way, negative electrode one tunnel of those diodes D3 and D4 connects power supply, another takes turns the positive pole meeting polar capacitor C11 and C12 in parallel in the same way, the minus earth of those polar capacitors C11 and C12, those polar capacitors C11 and C12 is also parallel with a resistance R22; Output 8 pin of described transformer T1 connects with 7 pin, this output 10 pin connects the anode of diode D5 and D6 in parallel in the same way, the negative electrode of those diodes D5 and D6 connects the positive pole of polar capacitor C14 and C15 in parallel in the same way, the minus earth of this polar capacitor C14 and C15, the negative electrode of described diode D5 and D6 also connects power supply, the output 7 pin ground connection of described transformer.
After the utility model normally works, when field effect transistor Q2 conducting, then to primary charging, and secondary due to diode reverse cut-off, and transformer can not to secondary transferring energy; When field effect transistor Q2 turns off, primary forms electric current return circuit, secondary diode positively biased, and transformer charges to secondary capacitance, to loading functional, is referred to as flyback; The FEEDBACK CONTROL of flyback has the time delay of half period, and after detection output voltage is higher or on the low side, the duty ratio of adjustment will be closed have no progeny at next cycle and field effect transistor Q2 and could be transmitted and embody secondary.
The above, only better enforcement of the present utility model, not any pro forma restriction is done to the utility model, any those skilled in the art may utilize above-mentioned technology contents to be changed or be modified to the Equivalent embodiments of equivalent variations, at this, allly do not depart from the technical solution of the utility model content, the any simple modification just done above embodiment according to technical spirit of the present utility model, equivalent variations and modification, all still belong in the scope of technical solutions of the utility model.
Claims (1)
1. a New LED TV circuit of reversed excitation, comprises chip U1, and triode Q1, field effect transistor Q2 and transformer T1, is characterized in that, the 1 pin ground connection of described chip U1; 2 pin of described chip U1 connect 4 pin of optical coupler PC, the 3 pin ground connection of this optical coupler PC, and this optical coupler PC is also parallel with an electric capacity C1; 3 pin of described chip U1 connect ground connection after a resistance R1; The 4 pin one road connecting resistance R7 of described chip U1 connect the source electrode of field effect transistor Q2, and another road connects ground connection after the RC parallel circuits be made up of resistance R4 and electric capacity C2; 5 pin one tunnels of described chip U1 meet power supply VCC, connect the first power end after another road series resistor R2 and resistance R3, and the 3rd tunnel connects ground connection after an electric capacity C3, and the 4th tunnel connects the positive pole of polar capacitor C7, the minus earth of this electric capacity C7; Connect the base stage of triode Q1 after the 6 pin one road connecting resistance R6 of described chip U1, after the connecting resistance R5 of another road, connect the emitter of triode Q1; The emitter of this triode Q1 connects the grid of field effect transistor Q2; The source electrode of field effect transistor Q2 is connect after the collector electrode connecting resistance R9 of described triode Q1; Be connected to resistance R10 between the grid of described field effect transistor Q2 and source electrode, between source electrode and drain electrode, be connected to electric capacity C6, ground connection after the source electrode connecting resistance R11 of this field effect transistor Q2; The drain electrode of described field effect transistor Q2, one tunnel connects the anode of diode D1, another road connects the positive pole of rectifier diode D7, the negative pole of this rectifier diode D7 connects transformer T1 input 5 pin, second source end is connect after the negative electrode one road connecting resistance R12 of this diode D1, second source end is connect, the positive pole of this second source termination polar capacitor C5, the minus earth of this polar capacitor C5 after another road serial capacitance C4 and resistance R14 in parallel and resistance R13; Input 4 pin of described transformer connects second source end; Input 1 pin of described transformer T1 connects diode D2 in parallel in the same way and the anode of diode D7, and the negative electrode of this diode D2 and diode D7 connects the positive pole of polar capacitor C7; The input 2 pin ground connection of described transformer T1; Power supply is connect after the output 12 pin one road serial capacitance C10 of described transformer T1 and resistance R18,19,20,21 in parallel, another road connects the anode of diode D3 and D4 in parallel in the same way, negative electrode one tunnel of those diodes D3 and D4 connects power supply, another takes turns the positive pole meeting polar capacitor C11 and C12 in parallel in the same way, the minus earth of those polar capacitors C11 and C12, those polar capacitors C11 and C12 is also parallel with a resistance R22; Output 8 pin of described transformer T1 connects with 7 pin, this output 10 pin connects the anode of diode D5 and D6 in parallel in the same way, the negative electrode of those diodes D5 and D6 connects the positive pole of polar capacitor C14 and C15 in parallel in the same way, the minus earth of this polar capacitor C14 and C15, the negative electrode of described diode D5 and D6 also connects power supply, the output 7 pin ground connection of described transformer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520473661.6U CN204761573U (en) | 2015-07-05 | 2015-07-05 | Novel LED TV flyback converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520473661.6U CN204761573U (en) | 2015-07-05 | 2015-07-05 | Novel LED TV flyback converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204761573U true CN204761573U (en) | 2015-11-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520473661.6U Expired - Fee Related CN204761573U (en) | 2015-07-05 | 2015-07-05 | Novel LED TV flyback converter |
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| Country | Link |
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| CN (1) | CN204761573U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105703611A (en) * | 2016-03-11 | 2016-06-22 | 深圳市华星光电技术有限公司 | Voltage feedback circuit of flyback switching power supply and flyback switching power supply |
-
2015
- 2015-07-05 CN CN201520473661.6U patent/CN204761573U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105703611A (en) * | 2016-03-11 | 2016-06-22 | 深圳市华星光电技术有限公司 | Voltage feedback circuit of flyback switching power supply and flyback switching power supply |
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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: 20151111 Termination date: 20190705 |