CN202404873U

CN202404873U - Constant voltage and constant current drive circuit of LED display screen

Info

Publication number: CN202404873U
Application number: CN2011204545288U
Authority: CN
Inventors: 傅新舵
Original assignee: WUHAN LIGHT ENERGY TECHNOLOGY CO LTD
Current assignee: WUHAN LIGHT ENERGY TECHNOLOGY CO LTD
Priority date: 2011-11-16
Filing date: 2011-11-16
Publication date: 2012-08-29
Anticipated expiration: 2021-11-16

Abstract

A constant voltage and constant current drive circuit of an LED display screen is provided. The circuit comprises a voltage-stabilizing power supply, a constant voltage circuit and a plurality of constant current drive circuits, the constant voltage circuit is connected with the output end of a DC voltage-stabilizing power supply, the constant current drive circuits are connected with the output end of the constant voltage circuit in parallel, and each constant current circuit is respectively connected with an LED lamp. Compared with the prior art, the circuit is more convenient and flexible for using, the constant voltage power supply is used to drive the constant current circuits, the constant current circuits are respectively used for driving the LED lamp group, thus current passing through the LEDs is consistent as possible, consistency of brightness and chroma of each LED is guaranteed, and work of other lamp groups will not be influenced when a certain LED of a certain lamp group is damaged. A constant current control chip ZXLD1350 with low power consumption, mature technology and low costs is adopted as a constant current circuit, and power supply efficiency and costs are all considered.

Description

The constant pressure and flow driving circuit of LED display

Technical field

The utility model relates to a kind of television PC driving circuit, relates in particular to a kind of constant pressure and flow driving circuit of LED display.

Background technology

LED display is meant the display screen that is used as backlight with LED (light emitting diode).LED display mainly comprises array, driving circuit, control system and transmission interface that light emitting diode constitutes and corresponding application software etc.; The quality of design of drive circuit wherein plays a part very important to the runnability of display effect, cost of manufacture and the system of LED display.So design and a kind ofly can satisfy the driving requirement, it is necessary using the LED control Driver Circuit that device is few, cost is low simultaneously.

LED drives and is broadly divided into resistance current-limiting mode, DC-DC mode and constant current drive mode etc.Resistance current-limiting mode cost is minimum, but the LED working current can not accurately be set, and causes LED to descend serviceable life, more can not accurately regulate brightness, only tightens at cost, uses under the not high occasion of performance requirement.It is low in energy consumption that the LED of DC-DC mode drives advantage, but because external circuit is complicated, uses on high-power LED illumination usually.Constant current drive mode controlled current and high conformity; The can yet be regarded as first-selection of LED driving power, but LED-backlit constant current plate in the market generally is direct constant current power supply, the operation of LED serial or parallel connection; Its dirigibility is relatively poor, and certain LED fault will influence the normal operation of other LED.

Summary of the invention

The problem that the utility model need solve provides a kind of energy-conservation, good stability and uses the constant pressure and flow driving circuit of LED display flexibly.

For addressing the above problem; The technical scheme that the utility model adopts is: a kind of constant pressure and flow driving circuit of LED display; Comprise D.C. regulated power supply, a constant voltage circuit and a plurality of constant-current drive circuit, wherein D.C. regulated power supply has the pwm signal end, and said constant voltage circuit is connected with the D.C. regulated power supply input end; A plurality of constant-current drive circuits are parallel to be connected in the constant voltage circuit output terminal, and each constant-current drive circuit is connected with a LED lamp group respectively.

As preferably, said constant voltage drive circuit adopts the DC-DC change-over circuit.

As preferably, said constant-current drive circuit comprises constant current control chip ZXLD1350, and its 3 pin inserts the pwm signal end that D.C. regulated power supply provides; 5 pin connect the constant voltage circuit output terminal; 1 pin connects LED lamp group negative pole through inductance, 2 pin ground connection, and the constant voltage circuit output terminal is also anodal through connecing LED lamp group after the resistance current limliting; 4 pin of constant current control chip connect the anodal feedback signal of LED lamp group, are connected a stabilivolt between 1 pin and 5 pin.

As preferably, compose in parallel again after said LED lamp group is connected by a plurality of LED or a plurality of LED connects.

Compared with prior art, the utility model uses convenient flexible.It adopts a constant pressure source to drive a plurality of constant-current circuits; A plurality of constant-current circuits drive the form of a plurality of LED lamp groups respectively; Make the size of current that flows through each LED consistent as far as possible, guarantee the consistance of each LED brightness, colourity, when indivedual LED of individual lamps group damage, do not influence other lamp group work.That constant-current circuit adopts is low in energy consumption, technology maturation and lower-cost constant current control chip ZXLD1350, can take into account power-efficient and cost simultaneously.

Description of drawings

Fig. 1 is the principle schematic of the said constant voltage circuit of the utility model;

Fig. 2 is the principle schematic of the said constant-current drive circuit of the utility model.

Embodiment

Below in conjunction with embodiment and accompanying drawing the utility model is done further to specify.

The constant pressure and flow driving circuit of the LED display that the utility model disclosed; Comprise D.C. regulated power supply, a constant voltage circuit and a plurality of constant-current drive circuit; Wherein D.C. regulated power supply has the pwm signal end; Constant voltage circuit is connected with stream stabilized voltage supply input end, and a plurality of constant-current drive circuits are parallel to be connected in the constant voltage circuit output terminal, and each constant-current drive circuit is connected with a LED lamp group respectively.

Wherein, Constant voltage circuit adopts the DC-DC change-over circuit; As shown in Figure 1; This DC-DC change-over circuit adopts DC voltage conversion chip BIT3251, and its input end is connected with output terminal VCC, the GND terminal of direct supply (PWM switching mode voltage stabilizer) P1, and direct supply is given DC-DC conversion chip BIT3251 power supply through triode Q2 after capacitor C 3 and C2 filtering.Conducting through inductance L 1 energy storage and pulse-width controlled triode Q4 is by the conversion purpose that reaches DC-DC again, and ripple, low noise DC voltage can be stablized, hanged down to DC-DC change-over circuit output terminal after through schottky diode D1 rectification and capacitor C 7 filtering.Resistance R 9 is sampled to output voltage with R10, and output voltage changes thereupon when input voltage or load change, and BIT3251 will regulate dutycycle according to sampled result, reaches the purpose of regulated output voltage.

Wherein, constant-current drive circuit is as shown in Figure 2, comprises constant current control chip ZXLD1350; Its 3 pin inserts the pwm signal end that direct supply P1 provides, and 5 pin connect constant voltage circuit output end vo ut-in, and 1 pin connects LED lamp group negative pole through inductance; 2 pin ground connection; The constant voltage circuit output terminal is also anodal through connecing LED lamp group after the resistance current limliting, and 4 pin of constant current control chip connect the anodal feedback signal of LED lamp group, is connected a stabilivolt between 1 pin and 5 pin.LED lamp group composes in parallel by a plurality of LED series connection or after connecting again.

In the present embodiment, each constant-current drive circuit all adopts constant current control IC ZXLD1350 control, and ZXLD1350 is a buck regulator of being derived by controllable current source, and this device can be used to drive high-power, the high brightness LED lamp group of series connection.The acceptable wide input voltage range of this control chip; (DC12-30V); As long as the combination feed-forward voltage of led array is no more than 30V, this circuit just can keep the adjusting electric current among the LED of any amount constant, and the while can also be carried out light modulation to led array through the PWM pulse-width signal.

Need to prove, more than be merely the utility model preferred embodiment, do not breaking away under the utility model design prerequisite any impartial protection domain of in the prior art scope, the utility model circuit being done that all belongs to the utility model with modification that changes.

Claims

1. the constant pressure and flow driving circuit of a LED display; Comprise D.C. regulated power supply, a constant voltage circuit and a plurality of constant-current drive circuit; Wherein D.C. regulated power supply has the pwm signal end; It is characterized in that said constant voltage circuit is connected with the D.C. regulated power supply input end, a plurality of constant-current drive circuits are parallel to be connected in the constant voltage circuit output terminal, and each constant-current drive circuit is connected with a LED lamp group respectively.

2. the constant pressure and flow driving circuit of LED display according to claim 1 is characterized in that said constant voltage drive circuit adopts the DC-DC change-over circuit.

3. the constant pressure and flow driving circuit of LED display according to claim 2 is characterized in that said constant-current drive circuit comprises constant current control chip ZXLD1350, and its 3 pin inserts the pwm signal end of D.C. regulated power supply; 5 pin connect the constant voltage circuit output terminal; 1 pin connects LED lamp group negative pole through inductance, 2 pin ground connection, and the constant voltage circuit output terminal is also anodal through connecing LED lamp group after the resistance current limliting; 4 pin of constant current control chip connect the anodal feedback signal of LED lamp group, are connected a stabilivolt between 1 pin and 5 pin.

4. the constant pressure and flow driving circuit of LED display according to claim 3 is characterized in that composing in parallel after said LED lamp group is by a plurality of LED series connection or a plurality of LED series connection again.