CN103680421A - LED backlight drive circuit - Google Patents

The invention discloses an LED backlight drive circuit comprising a DC (direct current) power supply, a BOOST circuit, and an operational amplifier LED self-constant-current and dimming circuit. The DC power supply is directly connected with the BOOST circuit, the output end of the BOOST circuit is respectively connected with an MCU (micro controller unit) control circuit and positive electrodes of LED string lights, the output end of the MCU control circuit is respectively connected with the operational amplifier LED self-constant-current and dimming circuit and a feedback protection sampling circuit, and the feedback protection sampling circuit is connected with negative electrodes of the LED string lights. The LED backlight drive circuit is simple in structure, durable and cheap. The BOOST and the MCU dimming are combined in the system, the MCU is directly used for dimming of the LED, and special dimming chips are omitted; due to the programmable characteristic of the MCU, the drive circuit can be used as the protection circuit and the feedback circuit, the original circuit is simplified, the subsequent maintenance can be achieved by means of upgrading of programs, and PCB (printed circuit board) rerouting is omitted.

A kind of LED-backlit lamp drive circuit

Technical field

The present invention relates to LED technical field, be specifically related to a kind of LED backlight driving circuit.

Background technology

Now, increasing LCD TV all starts to adopt the backlight technology of LED, and its major advantage is long service life, power and energy saving, and drives conveniently.For LED scheme backlight, mainly contain following two kinds: a kind of is straight-down negative, by some LED lamps, be set directly at the below of display screen, thereby in the display frame by lighting this LED backlight whenever necessary.Another kind is side entering type, and some LED lamps are distributed on the side of display screen, whenever necessary, lights described LED-backlit lamp, and by the light guide plate that be arranged in parallel with display screen by the light display screen that leads equably, to reach the object of display frame.

At present, above-mentioned two schemes has all obtained several application widely.Wherein, the described LED backlight of arranging by vertical type or side entering type is normally connected several LED lamps, and then the combination of a few string LED lamps is driven and lighted by one or several constant current driven IC.

Day by day universal along with current LCD TV, people are also more and more extensive and harsh for the requirement of LCD TV, for example, and along with the release of 3D TV and weeding out the old and bring forth the new of all big enterprises, people are also all to enter with day for the requirement of 3D, have even arrived hairsplitting stage.At present, the mode that realizes 3D TV functions has multiple, and wherein ripe, the best mode of effect is: adopt the mode of liquid crystal electron light valve spectacles to realize 3D TV functions.In which, be provided with a synchronization signal generation apparatus and synchronous receiving trap, LCD TV shows the image frame of left eye and right eye according to certain rules successively.Above-mentioned synchronous receiving trap receives the liquid crystal light valve that corresponding synchronizing signal is controlled respectively right and left eyes, thereby allows right and left eyes see respectively corresponding image frame, so in people's brain the image frame of compound stereoscopic, realize the function of 3D.But; due in the handoff procedure of liquid crystal light valve; liquid crystal light valve has the delay of opening and turn-offing; like this; people can produce the situation that hangover and ghost image appear in its image frame of seeing conventionally; even an one eye can be seen the content of another glasses, thereby cause the fatigue of eyes, affect normally watching of user.In addition, liquid crystal light valve also can cause the decay to light in to the handoff procedure of light, therefore under this 3D functional status, the image frame that user can watch is darker, has therefore also caused to a certain extent user's eyes uncomfortable.

Summary of the invention

Goal of the invention of the present invention is: for the problem of above-mentioned existence, provide a kind of simple in structure, durable, LED backlight driving circuit that cost is low, effective.

The technical solution used in the present invention is such: comprise that DC power supply, BOOST circuit and amplifier LED are from constant current and light adjusting circuit; wherein; DC power supply is directly connected with BOOST circuit; the output terminal of BOOST circuit is connected with the positive pole of LED lamp string respectively at MCU control circuit; the output terminal of MCU control circuit is connected with feedback protection sample circuit from constant current and light adjusting circuit with amplifier LED respectively, and feedback protection sample circuit is connected with the negative pole of LED lamp string.

Further, the quantity of described LED lamp string is 4 ~ 8 tunnels.

Further, described amplifier LED is 4 ~ 8 tunnels from the controlled quentity controlled variable of constant current and light adjusting circuit.

Further, described MCU control circuit is selected 28 pin flash memory single-chip microcomputers: Singlechip clock frequency 16MHz, 25,11 I/O mouths of A/D mouth, timer 2.

In sum; beneficial effect of the present invention is: simple in structure, durable, cost is low; and the mode that this system adopts Boost and MCU light modulation to combine; because MCU directly carries out light modulation to LED, saved special-purpose light modulation chip, and because MCU has programmable feature; can be used for holding circuit and feedback circuit; simplify original circuit, in follow-up maintenance, only need just can realize program upgrade, do not needed cloth PCB again.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the present invention is further described.

Fig. 1 is schematic diagram of the present invention.

Embodiment

In conjunction with the accompanying drawings, the present invention is further detailed explanation.These accompanying drawings are the schematic diagram of simplification, basic structure of the present invention is only described in a schematic way, so it only show the formation relevant with the present invention.

As shown in Figure 1; a kind of LED-backlit lamp drive circuit; comprise that DC power supply, BOOST circuit and amplifier LED are from constant current and light adjusting circuit; wherein; DC power supply is directly connected with BOOST circuit; the output terminal of BOOST circuit is connected with the high-pressure side of LED lamp string respectively at MCU control circuit, and the output terminal of MCU control circuit is connected with feedback protection sample circuit from constant current and light adjusting circuit with amplifier LED respectively, and feedback protection sample circuit is connected with the low pressure end of LED lamp string.

Further, the quantity of described LED lamp string is 4 ~ 8 tunnels.

Further, described amplifier LED is 4 ~ 8 tunnels from the controlled quentity controlled variable of constant current and light adjusting circuit.

Further, described MCU control circuit is selected 28 pin flash memory single-chip microcomputers: Singlechip clock frequency 16MHz, 25,11 I/O mouths of A/D mouth, timer 2.

When operation, shown in Fig. 1.Power panel provides a direct supply DC to enter the driving that Boost circuit is LED: the control center that MCU control circuit is whole system, be responsible for the processing of signal: feedback protection sample circuit for the low pressure end voltage of the LED that samples and by signal feedback to MCU control circuit: amplifier LED constant current and light adjusting circuit directly act on the low pressure end of LED for receiving the control signal of MCU control circuit.The string number of LED and a number of every string capable of regulating all in Fig. 1, as long as adjust the parameter of Boost circuit and select the MCU control circuit of corresponding l/O mouth number.

The above-mentioned foundation desirable embodiment of the present invention of take is enlightenment, and by above-mentioned description, relevant staff can, within not departing from the scope of this invention technological thought, carry out various change and modification completely.The technical scope of this invention is not limited to the content on instructions, must determine its technical scope according to claim scope.