CN203055409U - Led backlight drive circuit and liquid crystal display device - Google Patents
Led backlight drive circuit and liquid crystal display device Download PDFInfo
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- CN203055409U CN203055409U CN 201320057631 CN201320057631U CN203055409U CN 203055409 U CN203055409 U CN 203055409U CN 201320057631 CN201320057631 CN 201320057631 CN 201320057631 U CN201320057631 U CN 201320057631U CN 203055409 U CN203055409 U CN 203055409U
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Abstract
The utility model discloses an LED backlight drive circuit and a liquid crystal display device. The drive circuit comprises a boost circuit and a driver chip. The boost circuit comprises a power input terminal, voltage output terminals, a switching device, a first capacitor and a coupling inductance. A positive pole of the power input terminal is connected with a dotted terminal of a primary coil of the coupling inductance. A negative pole of the power input terminal is connected with a first end of the switching device. A second end of the switching device is connected with a different-name end of the primary coil of the coupling inductance, and is connected with a dotted terminal of a secondary coil of the coupling inductance. A control end of the switching device is connected with the driver chip. A different-name end of the secondary coil of the coupling inductance is connected with a first end of the first capacitor. A second end of the first capacitor is connected with a negative pole of the power input terminal. Two ends of the first capacitor lead out the voltage output terminals. The LED backlight drive circuit and the boost circuit in the liquid crystal display device use the coupling inductance. Compared with an existing boost circuit, output voltage is improved, and the LED backlight drive circuit and the liquid crystal display device are suitable to be used in large-size LCD TVs.
Description
Technical field
The utility model relates to field of liquid crystal display.
Background technology
Along with the development of the whole industry of semiconductor, the development of LCD TV is also more and more faster.Throw oneself into the also more and more growth of team of R﹠D work, the division of labor is also just more and more detailed like this, and liquid crystal TV set is divided into mainboard, power panel, T-CON plate, drive plate aspect circuit.On the drive plate because present televisor has the SG3D function, just produced on the drive plate some new LED control circuits (mcu+ specialty light modulation chip) like this between power panel output and LED lamp anode with regard to special booster circuit of demand.Tradition LED booster circuit as shown in Figure 1, this circuit comprises inductance L 901, L902, diode VD904 and electronic switch V901, when electronic switch V901 was closed, direct supply input 100V was inductance L 901 energy storage; When electronic switch V901 disconnected, the voltage of the energy storage of inductance L 901 and direct supply input was superimposed, and the voltage after the stack is exported thereby the low-voltage that direct supply is imported is become high voltage by capacitor C 939 discharges of diode VD904.This circuit can only drive the LED lamp of relative lesser amt, and it is not high to drive efficient.Because expanding economy, the raising of consumer spending ability makes LED large scale 3D TV become a kind of main flow, and traditional small size LCD TV is gradually by marginalisation, and traditional booster circuit can't satisfy mainstream demand.
The utility model content
At the problem that prior art exists, the purpose of this utility model is to provide a kind of LED-backlit driving circuit and liquid crystal indicator that can satisfy the large scale liquid crystal TV, improve the step-up ratio of circuit.
For achieving the above object, LED-backlit driving circuit of the present utility model, comprise booster circuit and drive chip, described booster circuit comprises power input, voltage output end, switching device, first electric capacity and coupling inductance, the positive pole of power input is connected with the end of the same name of the primary coil of coupling inductance, the negative pole of power input is connected with first end of described switching device, second end of switching device is connected with the different name end of the primary coil of described coupling inductance, and be connected with the end of the same name of the secondary coil of coupling inductance, the control end of switching device is connected with described driving chip, by driving the break-make of chip controls switching device, the different name end of the secondary coil of described coupling inductance connects first end of described first electric capacity, second end of first electric capacity is connected with the negative pole of described power input, draws described voltage output end from the two ends of first electric capacity.
Further, described booster circuit also comprises one first diode, the anode of described first diode is connected with the different name end of the primary coil of second end of described switching device and described coupling inductance respectively, and the negative electrode of first diode is connected with the end of the same name of the secondary coil of described coupling inductance.
Further, described booster circuit also comprises second electric capacity, one end of described second electric capacity is connected with the end of the same name of the primary coil of described coupling inductance and the positive pole of described power input respectively, and the other end of second electric capacity is connected with the end of the same name of the secondary coil of the negative electrode of described first diode and described coupling inductance respectively.
Further, described booster circuit also comprises one second diode, and the anode of described second diode is connected with the different name end of the secondary coil of described coupling inductance, and the negative electrode of second diode is connected with described voltage output end with first end of described first electric capacity respectively.
Further, described booster circuit also comprises the 4th diode of two forward parallel connections, the anode pool side of two the 4th diodes is connected with the different name end of the primary coil of second end of described switching device and described coupling inductance respectively, and the negative electrode pool side of two the 4th diodes is connected with the end of the same name of the secondary coil of described coupling inductance.
Further, described booster circuit also comprises second electric capacity, one end of described second electric capacity is connected with the end of the same name of the primary coil of described coupling inductance and the positive pole of described power input respectively, and the other end of second electric capacity is connected with the end of the same name of the secondary coil of the negative electrode pool side of described two the 4th diodes and described coupling inductance respectively.
Further, described booster circuit also comprises five or two-utmost point pipe of two forward parallel connections, the anode pool side of two the 5th diodes is connected with the different name end of the secondary coil of described coupling inductance, and the negative electrode pool side of two the 5th diodes is connected with described voltage output end with first end of described first electric capacity respectively.
Further, described booster circuit also comprises one the 3rd diode, and described the 3rd diode is in parallel with described switching device.
Further, described LED-backlit driving circuit also comprises under-voltage protecting circuit, overvoltage crowbar, overpower protection circuit and the feedback circuit that is connected with described driving chip respectively.
Liquid crystal indicator of the present utility model comprises above-mentioned LED-backlit driving circuit.
Booster circuit in the LED-backlit driving circuit of the present utility model has adopted coupling inductance, compare existing booster circuit, improved output voltage, while is so high at the voltage at the primary coil place of coupling inductance, so can adopt the low switching device of withstand voltage, make contribution for the reduction of integrated circuit cost.
Description of drawings
Fig. 1 is the circuit diagram of the booster circuit of existing LED LCD TV;
Fig. 2 is the structural representation of the booster circuit of LED LCD TV of the present utility model;
Fig. 3 is the circuit diagram of the embodiment 1 of the utility model LED-backlit driving circuit;
Fig. 4 is the circuit diagram of the embodiment 2 of the utility model LED-backlit driving circuit;
Fig. 5 is the circuit diagram of the embodiment 3 of the utility model LED-backlit driving circuit;
Fig. 6 is the circuit diagram of the embodiment 4 of the utility model LED-backlit driving circuit.
Embodiment
Below in conjunction with drawings and Examples, embodiment of the present utility model is described in further detail.Following examples are used for explanation the utility model, but do not limit scope of the present utility model.
As shown in Figure 2, driving circuit of the present utility model comprises booster circuit and drives the chip (not shown), comprise power input, voltage output end, switching device K1, polar capacitor C1 and coupling inductance TR, the positive pole of power input is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the negative pole of power input is connected with the end of switching device K1, the other end of switching device K1 is connected with the different name end of the primary coil L1 of coupling inductance TR, and be connected with the end of the same name of the secondary coil L2 of coupling inductance TR, the control end of described driving chip and switching device K1 is connected, by driving the transmit control signal break-make of gauge tap device K1 of chip, the different name end of the secondary coil L2 of coupling inductance TR connects the positive pole of polar capacitor C1, the negative pole of polar capacitor C1 is connected with the negative pole of power input, and described voltage output end is drawn to LED lamp outputting drive voltage in the two ends of polar capacitor C1.
Booster circuit in the driving circuit of the present utility model has adopted coupling inductance TR, when driving chip controls switching device K1 unlatching, the flow through primary coil L1 of coupling inductance TR of electric current, and self-induction goes out a voltage, be coupled out another voltage for simultaneously the secondary coil L2 of coupling inductance TR, when driving chip controls switching device K1 closes, the voltage reversal of inductance, the voltage direction of two coils is consistent to superpose, so can rise from than the original voltage that coil is high.In addition, many turn ratio variable N in step-up formula, the turn ratio of suitable selection coupling inductance can reduce dutycycle, thereby has avoided traditional booster circuit dutycycle should not too big restriction; On the other hand, after coupling inductance replaces Boost inductance in traditional booster circuit, the voltage stress of switching device reduces greatly, this just can select the switching device of low-voltage, high-current, the on state resistance of such device is smaller, and therefore the efficient of driving circuit of the present utility model is in general than higher.
As shown in Figure 3, booster circuit in the utility model driving circuit, comprise metal-oxide-semiconductor V734, polar capacitor C1, coupling inductance TR, diode group VD702 and diode group VD704, the 24V power supply is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the drain electrode of metal-oxide-semiconductor V734 connects resistance R 5 back ground connection, the source electrode of metal-oxide-semiconductor V734 is connected with the different name end of the primary coil L1 of coupling inductance TR, and be connected with the anode pool side of two forward diode connected in parallel VD702, the negative electrode pool side of two forward diode connected in parallel VD702 is connected with the end of the same name of the secondary coil L2 of coupling inductance TR, the different name end of the secondary coil L2 of coupling inductance TR is connected with the anode pool side of two forward diode connected in parallel VD704, the negative electrode pool side of two forward diode connected in parallel VD704 is connected with the positive pole of polar capacitor C1, the minus earth of polar capacitor C1, polar capacitor C1 are drawn described voltage output end to LED lamp outputting drive voltage.
Add two groups of forward diode connected in parallel VD702, VD704 in the booster circuit of the present utility model, adopted two forward diode connected in parallel can reduce the electric current that each diode flows through in the present embodiment, played the effect in serviceable life of two diodes of prolongation.
As shown in Figure 4, booster circuit in the utility model driving circuit, comprise metal-oxide-semiconductor V734, polar capacitor C1, coupling inductance TR, capacitor C 20, diode group VD702 and diode group VD704, the 24V power supply is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the drain electrode of metal-oxide-semiconductor V734 connects resistance R 5 back ground connection, the source electrode of metal-oxide-semiconductor V734 is connected with the different name end of the primary coil L1 of coupling inductance TR, and be connected with the anode pool side of two forward diode connected in parallel VD702, the negative electrode pool side of two forward diode connected in parallel VD702 is connected with the end of the same name of the secondary coil L2 of an end of capacitor C 20 and coupling inductance TR respectively, the other end of capacitor C 20 is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the different name end of the secondary coil L2 of coupling inductance TR is connected with the anode pool side of two forward diode connected in parallel VD704, the negative electrode pool side of two forward diode connected in parallel VD704 is connected with the positive pole of polar capacitor C1, the minus earth of polar capacitor C1, polar capacitor C1 are drawn described voltage output end to LED lamp outputting drive voltage.
Present embodiment is compared with embodiment 1 and has been added capacitor C 20 therein, and the reverse voltage that produces at diode VD702 when capacitor C 20 can be eliminated conversion plays the effect of this diode of protection.
As shown in Figure 5, booster circuit in the utility model driving circuit, comprise metal-oxide-semiconductor V734, polar capacitor C1, coupling inductance TR, diode VD701 and diode VD703, the 24V power supply is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the drain electrode of metal-oxide-semiconductor V734 connects resistance R 5 back ground connection, the source electrode of metal-oxide-semiconductor V734 is connected with the different name end of the primary coil L1 of coupling inductance TR, and be connected with the anode of diode VD701, the negative electrode of diode VD701 is connected with the end of the same name of the secondary coil L2 of coupling inductance TR, the different name end of the secondary coil L2 of coupling inductance TR is connected with the anode of diode VD703, the negative electrode of diode VD703 is connected with the positive pole of polar capacitor C1, the minus earth of polar capacitor C1, polar capacitor C1 are drawn described voltage output end to LED lamp outputting drive voltage.
Present embodiment is compared with embodiment 1, and two forward diode connected in parallel VD702, VD704 are replaced with diode VD701, VD703.
As shown in Figure 6, booster circuit in the utility model driving circuit, comprise metal-oxide-semiconductor V734, polar capacitor C1, coupling inductance TR, capacitor C 20, diode VD701 and diode VD703, the 24V power supply is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the drain electrode of metal-oxide-semiconductor V734 connects resistance R 5 back ground connection, the source electrode of metal-oxide-semiconductor V734 is connected with the different name end of the primary coil L1 of coupling inductance TR, and be connected with the anode of diode VD701, the negative electrode of diode VD701 is connected with the end of the same name of the secondary coil L2 of an end of capacitor C 20 and coupling inductance TR respectively, the other end of capacitor C 20 is connected with the end of the same name of the primary coil L1 of coupling inductance TR, the different name end of the secondary coil L2 of coupling inductance TR is connected with the anode of diode VD703, the negative electrode of diode VD703 is connected with the positive pole of polar capacitor C1, the minus earth of polar capacitor C1, polar capacitor C1 are drawn described voltage output end to LED lamp outputting drive voltage.
Present embodiment is compared with embodiment 3 and has been added capacitor C 20 therein, and the reverse voltage that produces at diode VD701 when capacitor C 20 can be eliminated conversion plays the effect of this diode of protection.
The OUT pin of described driving chip of the present utility model (model AP3041) is connected with the grid of metal-oxide-semiconductor in the booster circuit, to its transmit button signal, and the switch of control metal-oxide-semiconductor.Driving circuit can also comprise under-voltage protecting circuit, overvoltage crowbar, overpower protection circuit and feedback circuit except booster circuit.As shown in Figure 3; under-voltage protecting circuit principle of work: when input voltage value is crossed when low; input voltage obtains a voltage by resistance R 1 and resistance R 2 dividing potential drops and compares for the UVLO pin of driving chip and the comparer of built-in chip type, if just turn off chip less than the reference voltage of comparer.The overvoltage crowbar principle of work: when the magnitude of voltage of exporting to the LED lamp was higher, when the magnitude of voltage of LED lamp between resistance R 6 and resistance R 7 was higher than the built-in reference voltage of chip OV pin, chip was closed.The overpower protection circuit: the electric current on the inductance of flowing through when output current is bigger can be very big, and when voltage was broken through the built-in comparator reference value of chip CS pin, chip was switched off.Feedback circuit: feedback circuit is divided to ground by the LED anode through resistance in series R6, R7, R8, and the voltage between resistance R 7 and the resistance R 8 feeds back to the dutycycle that chip FB pin decides the driven MOS pipe to open through built-in comparer.
The utility model also proposes a kind of liquid crystal indicator, and liquid crystal indicator can be the large scale liquid crystal TV, also can be large-sized liquid crystal display.This liquid crystal indicator comprises the LED-backlit driving circuit, and its LED-backlit driving circuit comprises booster circuit, and the circuit structure of this booster circuit is identical with the circuit structure of the described booster circuit of top embodiment, repeats no more herein.
Claims (10)
1.LED backlight drive circuit, it is characterized in that, comprise booster circuit and drive chip, described booster circuit comprises power input, voltage output end, switching device, first electric capacity and coupling inductance, the positive pole of power input is connected with the end of the same name of the primary coil of coupling inductance, the negative pole of power input is connected with first end of described switching device, second end of switching device is connected with the different name end of the primary coil of described coupling inductance, and be connected with the end of the same name of the secondary coil of coupling inductance, the control end of switching device is connected with described driving chip, by driving the break-make of chip controls switching device, the different name end of the secondary coil of described coupling inductance connects first end of described first electric capacity, second end of first electric capacity is connected with the negative pole of described power input, draws described voltage output end from the two ends of first electric capacity.
2. LED-backlit driving circuit according to claim 1, it is characterized in that, described booster circuit also comprises one first diode, the anode of described first diode is connected with the different name end of the primary coil of second end of described switching device and described coupling inductance respectively, and the negative electrode of first diode is connected with the end of the same name of the secondary coil of described coupling inductance.
3. LED-backlit driving circuit according to claim 2, it is characterized in that, described booster circuit also comprises second electric capacity, one end of described second electric capacity is connected with the end of the same name of the primary coil of described coupling inductance and the positive pole of described power input respectively, and the other end of second electric capacity is connected with the end of the same name of the secondary coil of the negative electrode of described first diode and described coupling inductance respectively.
4. LED-backlit driving circuit according to claim 3, it is characterized in that, described booster circuit also comprises one second diode, the anode of described second diode is connected with the different name end of the secondary coil of described coupling inductance, and the negative electrode of second diode is connected with described voltage output end with first end of described first electric capacity respectively.
5. LED-backlit driving circuit according to claim 1, it is characterized in that, described booster circuit also comprises the 4th diode of two forward parallel connections, the anode pool side of two the 4th diodes is connected with the different name end of the primary coil of second end of described switching device and described coupling inductance respectively, and the negative electrode pool side of two the 4th diodes is connected with the end of the same name of the secondary coil of described coupling inductance.
6. LED-backlit driving circuit according to claim 5, it is characterized in that, described booster circuit also comprises second electric capacity, one end of described second electric capacity is connected with the end of the same name of the primary coil of described coupling inductance and the positive pole of described power input respectively, and the other end of second electric capacity is connected with the end of the same name of the secondary coil of the negative electrode pool side of described two the 4th diodes and described coupling inductance respectively.
7. LED-backlit driving circuit according to claim 6, it is characterized in that, described booster circuit also comprises the 5th diode of two forward parallel connections, the anode pool side of two the 5th diodes is connected with the different name end of the secondary coil of described coupling inductance, and the negative electrode pool side of two the 5th diodes is connected with described voltage output end with first end of described first electric capacity respectively.
8. according to each described LED-backlit driving circuit of claim 1-7, it is characterized in that described booster circuit also comprises one the 3rd diode, described the 3rd diode is in parallel with described switching device.
9. LED-backlit driving circuit according to claim 1 is characterized in that, described LED-backlit driving circuit also comprises under-voltage protecting circuit, overvoltage crowbar, overpower protection circuit and the feedback circuit that is connected with described driving chip respectively.
10. liquid crystal indicator is characterized in that, described liquid crystal indicator comprises each described LED-backlit driving circuit as claim 1-9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320057631 CN203055409U (en) | 2013-01-31 | 2013-01-31 | Led backlight drive circuit and liquid crystal display device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320057631 CN203055409U (en) | 2013-01-31 | 2013-01-31 | Led backlight drive circuit and liquid crystal display device |
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| CN203055409U true CN203055409U (en) | 2013-07-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 201320057631 Expired - Lifetime CN203055409U (en) | 2013-01-31 | 2013-01-31 | Led backlight drive circuit and liquid crystal display device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103810958A (en) * | 2014-01-23 | 2014-05-21 | 北京京东方光电科技有限公司 | Driving circuit, working method of driving circuit and display device |
| CN104426367A (en) * | 2013-08-20 | 2015-03-18 | 硕颉科技股份有限公司 | Boost apparatus with over-current and over-voltage protection function |
| CN111031633A (en) * | 2020-01-09 | 2020-04-17 | Oppo广东移动通信有限公司 | Flash lamp driving circuit |
| WO2021035616A1 (en) * | 2019-08-29 | 2021-03-04 | 深圳市大疆创新科技有限公司 | Drive circuit, drive circuit board and driver |
-
2013
- 2013-01-31 CN CN 201320057631 patent/CN203055409U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104426367A (en) * | 2013-08-20 | 2015-03-18 | 硕颉科技股份有限公司 | Boost apparatus with over-current and over-voltage protection function |
| CN103810958A (en) * | 2014-01-23 | 2014-05-21 | 北京京东方光电科技有限公司 | Driving circuit, working method of driving circuit and display device |
| WO2015109788A1 (en) * | 2014-01-23 | 2015-07-30 | 京东方科技集团股份有限公司 | Driving circuit and operating method thereof and display device |
| CN103810958B (en) * | 2014-01-23 | 2017-02-08 | 北京京东方光电科技有限公司 | Driving circuit, working method of driving circuit and display device |
| US9698675B2 (en) | 2014-01-23 | 2017-07-04 | Boe Technology Group Co., Ltd. | Driving circuit, operation method thereof and display apparatus |
| WO2021035616A1 (en) * | 2019-08-29 | 2021-03-04 | 深圳市大疆创新科技有限公司 | Drive circuit, drive circuit board and driver |
| CN111031633A (en) * | 2020-01-09 | 2020-04-17 | Oppo广东移动通信有限公司 | Flash lamp driving circuit |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 266555 Qingdao economic and Technological Development Zone, Shandong, Hong Kong Road, No. 218 Patentee after: Hisense Video Technology Co.,Ltd. Address before: 266555 Qingdao economic and Technological Development Zone, Shandong, Hong Kong Road, No. 218 Patentee before: QINGDAO HISENSE ELECTRONICS Co.,Ltd. |
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| CP01 | Change in the name or title of a patent holder | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130710 |
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| CX01 | Expiry of patent term |