LED恒流驱动控制IC QX9910 英文资料

1、Switching Type LED Driver QX9910General Description QX9910 is a highly efficient, stable and reliable high-brightness LED lights controlled constant current driver IC, built-in high-precision comparators, off-time control circuit, the current drive and other circuits, especially for high-power, high

2、 brightness LED light more than string constant current driver. QX9910 fixed off-time control mode, the operating frequency up to 2.5MHz, allows the external inductor and filter capacitor, the volume decrease efficiency. off-time minimum time, through an external resistor and capacitor set, the oper

3、ating frequency can be changed according to user requirements. PWM signal at the EN-ended and can adjust the brightness of LED lights. By adjusting the external resistance, high brightness LED lamp can control the drive current to achieve the desired LED brightness constant brightness, high brightne

4、ss LED light streaming from a few milliamps of current to 1 Amp change.Features Programmable LED drive current programmed range of a few milliamps to 1 amp.High efficiency: better than 90%Wide input voltage range ：2.5V400VHigh frequencyAdjustable operating frequency: 10KHz2.5MHz Strong LED light fun

5、ction drive: LED light string from one to hundreds of high brightness LED lampsPWM adjustable brightness：By EN-side, adjust the LED brightnessApplications220V AC power supply LED lights; RGB LED lights big screen; 220V AC power LED lamp; LED backlighting flat panel displays; LED traffic warning ligh

6、ts; Constant current charger control; Universal constant current source.PinPin arrangementMaximum rated parameter valuesElectrical CharacteristicsTypical Application CircuitMain ApplicationCity Exchange 220V power supply LED lighting applicationsGreat merit of high brightness LED lamps, the case for

7、 the same brightness, saving approximately 80% more than incandescent, widely AC power lighting applications, a great alternative to both the power gradually, fever, short life incandescent trend.QX9910 particularly suitable for 110V/220V AC power for lighting, typical application shown in Figure 1,

8、 220V AC rectified through the rectifier bridge, will receive about 310V DC voltage. As QX9910 VDD power supply is 5.1 V, so through a resistor and a regulator to the IC power supply. In the MOSFET control voltage is high, MOSFET power switch turns on, inductor L stores energy when the control volta

9、ge is low, MOSFET off, inductor releases energy through the Schottky diode circuit to light up LED lights string.Circuit parameters:LED average currentIn Figure 1, working in continuous mode, LED current IL, the average shown in Figure 2.ILMAX is LED lamp by the maximum current .2.Determine the oper

10、ating frequencyFrequency by the TOFF pin connected to the ROSC and COSC set, ROSC received a VDD terminal, ROSC resistance the smaller the higher the frequency, COSC larger, lower frequency.The level of the operating frequency is determined based on actual usage. The higher operating frequency, the

11、inductor can be smaller, the lower the cost of the inductor.LED light-driven duty cycle D = Vout / Vin. For the MOSFET, on-time TON, TOFF off time for the MOSFET, (resting stage). Telogen is calculated as follows:If pin is not connected resistors and capacitors TOFF is:Circuit operating frequency is

12、 calculated as follows:If TOFF feet to 1000P capacitance, TOFF = 51ms, D = 0.1, F is the circuit operating frequency is about 20KHz.3.Choice of inductor LInductance L of the selection principle is to ensure that flow through the inductor current change is much less than the maximum current through t

13、he inductor value. In normal operation, the inductor is in a state of charge and discharge, when the input voltage and output voltage of the pressure is high, increase the value of the inductor, when the pressure-hour, you can use a smaller inductor.In order to reduce fluctuations in current flowing

14、 through the inductor, the circuit should operate in continuous mode. In continuous mode, IL minimum. In the resting stage, flow through the LED lights IL calculated as follows:In order to flow through the LED lamp current fluctuation is less than IL inductance should satisfy:General value to more t

15、han a few hundred micro-Hang Hang cents, depending on the application may be.4.RCS determined resistanceRCS resistance of different, you can set the drive current through the LED, R CS smaller, the output current increases. R CS selection formula is as follows:IL LED lights through the average curre

16、nt; general, fluctuations in current IL should be less than one-tenth of IL.The selection of MOSFETIn the case of 220V AC power supply, the first MOSFET to consider the pressure, the pressure higher than the general requirements MOSFET 600V. Secondly, according to the size of the lamp current LED dr

17、iver, select the IDS MOSFET the maximum current.Under normal circumstances, should use the I DS MOSFET the maximum current is the LED lamp drive current of more than 5 times. In addition the internal resistance of M OS F ET is smaller; R DS should be less than 0.5 in Europe the following, R DS small

18、er, loss in the M OS F ET tube power smaller, the higher the efficiency of the circuit changes.6.LED brightness adjustmentIncrease in the EN side PWM dimming signal, PWM signal generated by the CPU, but also by the other pulse signal generator, PWM duty cycle greater brightness brighter. LED brightness control using PWM, very convenient and flexible, is the most common dimming method, PWM frequency from Hz to tens of thousands of KHz.EN enabled terminalTermination in EN (low) to the time, QX9910