CN203276794U - Television LED backlight drive circuit - Google Patents
Television LED backlight drive circuit Download PDFInfo
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- CN203276794U CN203276794U CN 201320257284 CN201320257284U CN203276794U CN 203276794 U CN203276794 U CN 203276794U CN 201320257284 CN201320257284 CN 201320257284 CN 201320257284 U CN201320257284 U CN 201320257284U CN 203276794 U CN203276794 U CN 203276794U
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Abstract
The utility model discloses a television LED backlight drive circuit comprising a DC/DC conversion circuit and an LED string light which are driven by a PWM control chip, and a regulating circuit. One end of the LED string light is connected with the positive output end of the DC/DC conversion circuit, and the other end of the LED string light is connected with ground. The DC/DC conversion circuit comprises a sampling resistor. A sampling signal output end of a current sampling resistor is connected with a feedback signal input end of the PWM control chip. The regulating circuit comprises a television mainboard regulating signal input end and a regulating signal output end. The regulating signal output end of the regulating circuit is connected with the feedback signal input end of the PWM control chip. According to the television LED backlight drive circuit, the LED current can be regulated without changing the resistance value of the sampling resistor on a circuit board. If the television mainboard sends a control signal to change the standard voltage value of current negative feedback via the regulating circuit, the circuit board can adapt to flat televisions with different specifications or different LED module groups. Therefore, one kind of circuit board can adapt to the flat televisions with different specifications, and thus the production cost is reduced.
Description
[technical field]
The utility model relates to the LED-backlit driving circuit, relates in particular to a kind of televisor LED-backlit driving circuit.
[background technology]
LED has life-span length, environmental protection and energy saving and drives the advantages such as convenient, and the LED-backlit technology of flat panel TV is in the field of business just gradually generally to be adopted.
The principle of traditional televisor LED-backlit driving circuit as shown in Figure 1, comprise the DC/DC translation circuit and the LED lamp string that are driven by pwm chip, the cathode output end of one termination DC/DC translation circuit of LED lamp string, the current sampling resistor ground connection of the other end by being comprised of R18, R19 and R20, the contact of current sampling resistor and LED lamp string connects the feedback signal input end (5 pin) of pwm chip IC1 by time delay resistance R16.After the reference voltage (as 0.2V or 0.5V) that the voltage of current sampling resistor sampling end is ordered over FB, by negative feedback control switching tube Q1, realize closed loop current control.The shortcoming of this LED-backlit driving circuit is that a kind of circuit board of specification can only coordinate corresponding LED-backlit module usually, can not be general.Need to join different circuit boards for the flat panel TV of different size or different LED modules, the difference of various boards is that the resistance of sampling resistor (R18/R19/R20 in Fig. 1) is not identical.Backlight drive circuit can not generally increase accessory specification and deposit, has increased cost of products.
[summary of the invention]
The technical problems to be solved in the utility model is to provide a kind of televisor LED-backlit driving circuit that can adapt to the different LED module.
In order to solve the problems of the technologies described above, the technical solution adopted in the utility model is, a kind of televisor LED-backlit driving circuit, comprise the DC/DC translation circuit, LED lamp string and the regulating circuit that are driven by pwm chip, the cathode output end of one termination DC/DC translation circuit of LED lamp string, other end ground connection; The DC/DC translation circuit comprises sampling resistor, the feedback signal input end of the sampled signal output termination pwm chip of current sampling resistor, described regulating circuit comprises input end and the conditioning signal output terminal of TV SKD conditioning signal, the feedback signal input end of the conditioning signal output termination pwm chip of regulating circuit.
Above-described televisor LED-backlit driving circuit, regulating circuit comprises signal input resistance, the input end of a described TV SKD conditioning signal of termination of signal input resistance, the feedback signal input end of another termination pwm chip.
Above-described televisor LED-backlit driving circuit comprises the first filter capacitor, and signal input resistance comprises serial connection the first resistance and the second resistance, termination first resistance of the first filter capacitor and the tie point between the second resistance, other end ground connection.
Above-described televisor LED-backlit driving circuit comprises the second filter capacitor, the feedback signal input end of a termination pwm chip of the second filter capacitor, other end ground connection.
Above-described televisor LED-backlit driving circuit, the input end of the TV SKD conditioning signal of regulating circuit comprise the input end of the PWM pulse-width control signal that TV SKD is exported and/or the input end of the variable amplitude level signal that TV SKD is exported.
Above-described televisor LED-backlit driving circuit, the LED lamp is ganged up excess current sampling resistor ground connection, and the tie point of current sampling resistor and LED lamp string connects the feedback signal input end of pwm chip by time delay resistance.
Above-described televisor LED-backlit driving circuit, the switching tube of DC/DC translation circuit is by current sampling resistor ground connection, and the tie point of current sampling resistor and switching tube connects the feedback signal input end of pwm chip by time delay resistance.
The utility model LED-backlit driving circuit does not need to change the resistance of circuit board up-sampling resistance, just can adapt to the flat panel TV of different size or different LED modules as long as send control signal by TV SKD by the reference voltage value that regulating circuit changes Current Negative Three-Point Capacitance, a kind of circuit board can adapt to the panel TV set of different size, has reduced production cost.
[description of drawings]
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
Fig. 1 is the schematic diagram of prior art televisor LED-backlit driving circuit.
Fig. 2 is the schematic diagram of the utility model embodiment 1 televisor LED-backlit driving circuit.
Fig. 3 is the schematic diagram of the utility model embodiment 2 televisor LED-backlit driving circuits.
Fig. 4 is the schematic diagram of the utility model embodiment 3 televisor LED-backlit driving circuits.
[embodiment]
The principle of the utility model embodiment 1 televisor LED-backlit driving circuit as shown in Figure 2, comprise by pwm chip IC1(such as OB3350 or LD5850) the DC/DC translation circuit and the LED lamp string that drive, the cathode output end of one termination DC/DC translation circuit of LED lamp string, the other end is by current sampling resistor R18 ground connection, and the contact of current sampling resistor and LED lamp string connects the feedback signal input end (5 pin) of pwm chip IC1 by time delay resistance R16.Regulating circuit comprises a signal input resistance R17 and filter capacitor C5, the input port DIM of the TV SKD variable amplitude level signal of the termination regulating circuit of signal input resistance R17, the feedback signal input end (5 pin) of another termination pwm chip IC1, the feedback signal input end of the termination pwm chip IC1 of filter capacitor C5, other end ground connection.
The principle of the utility model embodiment 2 televisor LED-backlit driving circuits as shown in Figure 3, as different from Example 1, regulating circuit also comprises a signal input resistance R21 and filter capacitor C7.Resistance R 21 is connected with resistance R 17, the terminating resistor R21 of filter capacitor C7 and the tie point of resistance R 17, other end ground connection.The other end of resistance R 17 is as the feedback signal input end (5 pin) of the output termination pwm chip IC1 of regulating circuit, the other end of resistance R 21 is as the input end of the input termination regulating circuit of regulating circuit, this input end comprises two input ports, be the input port PWM of TV SKD PWM pulse-width control signal and the input port DIM of TV SKD variable amplitude level signal, can choose a use wantonly.
Now illustrate that with embodiment 2 principle of work of the present utility model: TV motherboard MCU sends the level that variable PWM pulse width signal or DA converter send variable amplitude, compensate as required through FB port level rear class LED lamp bar electric current is realized controlling, wherein resistance R 18 is sampling resistor.TV motherboard MCU sends variable PWM pulse width signal or DA converter and sends the sampled voltage acting in conjunction of the level of variable amplitude and current sampling resistor R18 output at the feedback signal input end (5 pin) of pwm chip IC1, control metal-oxide-semiconductor Q1, realize closed loop current control.In order to reach Optimal Control rear class LED electric current, need to satisfy several conditions take pwm chip IC1 as variable amplitude level and the rear class LED constant-current circuit coupling that main circuit component collocation mainboard MCU sends variable PWM pulse width signal or DA converter:
(1) the LED constant current value is: IC1 (FB pin) reference voltage V REF/R18, because resistance R 21, R17, R16, R18 and IC1 current feedback terminal connect, produce level by the different resistances that change resistance R 21, R17, R16, R18 the voltage of the feedback end (FB point) of pwm chip is compensated, thereby realize high precision constant current.
(2) in case resistance R 21, R17, R16, R18 resistance are determined, send the clamping of variable amplitude rear class LED electric current is just fixing along with mainboard MCU sends variable PWM pulse width signal or DA converter so, satisfy the requirement of the required setting electric current of LED lamp bar.
(3) resistance R in Fig. 3 21, R21 not only carry out also forming the RC low-pass filter with C5, C7 outside the dividing potential drop compensation with R18, mainly mainboard MCU or DA converter to be sent variable PWM pulse width signal carry out filtering, obtain mild DC level the feedback end of IC1 is carried out voltage compensation, realize rear class LED electric current control on demand.Satisfy the requirement of the backlight module of the different electric currents of Same Efficieney.
The principle of the utility model embodiment 3 televisor LED-backlit driving circuits as shown in Figure 4, as different from Example 2, TV motherboard MCU sends the level that variable PWM pulse width signal or DA converter send variable amplitude, compensates as required through CS port level rear class LED lamp string stream is realized controlling.Wherein resistance R 10 is the current sampling resistor of metal-oxide-semiconductor Q1, TV motherboard MCU sends variable PWM pulse width signal or DA converter and sends the sampled voltage acting in conjunction of the level of variable amplitude and current sampling resistor R10 output at the feedback signal input end (4 pin) of pwm chip IC1, control metal-oxide-semiconductor Q1, realize closed loop current control.In order to reach Optimal Control rear class LED electric current, need to satisfy several conditions take pwm chip IC1 as variable amplitude level and the rear class LED constant-current circuit coupling that main circuit component collocation mainboard MCU sends variable PWM pulse width signal or DA converter:
(1) the LED constant current value is: IC1 (FB pin) reference voltage V REF/R18, because resistance R 21, R17, R16, R9, R10 and IC1 current feedback terminal CS pin connect, produce level by the different resistances that change resistance R 21, R17, R16, R9, R10 the voltage of the feedback end (CS point) of pwm chip is compensated, thereby realize high precision constant current.It should be noted that different resistances by R21, R17, R16, R9, R10 produce level and the voltage of the feedback end (CS point) of pwm chip is compensated can not affect the loop of controlling Q1, need the accurate Calculation bucking voltage.When rear class LED electric current hour, loop will guarantee that Q1 can work.
(2) in case resistance R 21, R17, R16, R9, R10 resistance are determined, send the clamping of variable amplitude rear class LED electric current is just fixing along with mainboard MCU sends variable PWM pulse width signal or DA converter so, satisfy the requirement of the required setting electric current of LED lamp string.
(3) resistance R in Fig. 4 21, R21 R9, not only carry out with R10 that the dividing potential drop compensation is outer also forms the RC low-pass filter with C4, C7, mainly mainboard MCU or DA converter to be sent variable PWM pulse width signal carry out filtering, obtain mild DC level the feedback end of IC1 is carried out voltage compensation, realize rear class LED electric current control on demand.Satisfy the requirement of the backlight module of the different electric currents of Same Efficieney.
Claims (7)
1. a televisor LED-backlit driving circuit, comprise the DC/DC translation circuit and the LED lamp string that are driven by pwm chip, the cathode output end of a termination DC/DC translation circuit of LED lamp string, other end ground connection; The DC/DC translation circuit comprises sampling resistor, the feedback signal input end of the sampled signal output termination pwm chip of current sampling resistor, it is characterized in that, comprise regulating circuit, described regulating circuit comprises input end and the conditioning signal output terminal of TV SKD conditioning signal, the feedback signal input end of the conditioning signal output termination pwm chip of regulating circuit.
2. televisor LED-backlit driving circuit according to claim 1, it is characterized in that, regulating circuit comprises signal input resistance, the input end of a described TV SKD conditioning signal of termination of signal input resistance, the feedback signal input end of another termination pwm chip.
3. televisor LED-backlit driving circuit according to claim 2, it is characterized in that, comprise the first filter capacitor, signal input resistance comprises serial connection the first resistance and the second resistance, one termination the first resistance of the first filter capacitor and the tie point between the second resistance, other end ground connection.
4. televisor LED-backlit driving circuit according to claim 2, is characterized in that, comprises the second filter capacitor, the feedback signal input end of a termination pwm chip of the second filter capacitor, other end ground connection.
5. televisor LED-backlit driving circuit according to claim 1, it is characterized in that, the input end of the TV SKD conditioning signal of regulating circuit comprises the input end of the PWM pulse-width control signal that TV SKD is exported and/or the input end of the variable amplitude level signal that TV SKD is exported.
6. the described televisor LED-backlit of arbitrary claim driving circuit according to claim 1 to 5, it is characterized in that, the LED lamp is ganged up excess current sampling resistor ground connection, and the tie point of current sampling resistor and LED lamp string connects the feedback signal input end of pwm chip by time delay resistance.
7. the described televisor LED-backlit of arbitrary claim driving circuit according to claim 1 to 5, it is characterized in that, the switching tube of DC/DC translation circuit is by current sampling resistor ground connection, and the tie point of current sampling resistor and switching tube connects the feedback signal input end of pwm chip by time delay resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320257284 CN203276794U (en) | 2013-05-13 | 2013-05-13 | Television LED backlight drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320257284 CN203276794U (en) | 2013-05-13 | 2013-05-13 | Television LED backlight drive circuit |
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| Publication Number | Publication Date |
|---|---|
| CN203276794U true CN203276794U (en) | 2013-11-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320257284 Expired - Fee Related CN203276794U (en) | 2013-05-13 | 2013-05-13 | Television LED backlight drive circuit |
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| CN (1) | CN203276794U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103916006A (en) * | 2014-04-08 | 2014-07-09 | 江苏银河电子股份有限公司 | Drive circuit of inductive device |
| CN107680539A (en) * | 2017-09-30 | 2018-02-09 | 深圳市艾特智能科技有限公司 | The anti-lightning road of backlight |
| CN109308870A (en) * | 2018-08-28 | 2019-02-05 | 出门问问信息科技有限公司 | A kind of anti-flicker circuit and LED display |
-
2013
- 2013-05-13 CN CN 201320257284 patent/CN203276794U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103916006A (en) * | 2014-04-08 | 2014-07-09 | 江苏银河电子股份有限公司 | Drive circuit of inductive device |
| CN103916006B (en) * | 2014-04-08 | 2016-08-17 | 江苏银河电子股份有限公司 | A kind of drive circuit of perceptual device |
| CN107680539A (en) * | 2017-09-30 | 2018-02-09 | 深圳市艾特智能科技有限公司 | The anti-lightning road of backlight |
| CN109308870A (en) * | 2018-08-28 | 2019-02-05 | 出门问问信息科技有限公司 | A kind of anti-flicker circuit and LED display |
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| 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 |
Granted publication date: 20131106 |
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| CF01 | Termination of patent right due to non-payment of annual fee |