ST launches new white LED driver

STMicroelectronics days ago launched a special device to drive a white LED, white LED has been applied in the LCD backlight or portable devices more widely.

Color LCD requires a pure white background light, so that the screen will display the correct color. Therefore, the white LED is becoming an ideal technology for such applications, however, the white LED requires a positive voltage of 3V DC to 4V DC. The latest lithium battery minimum operating voltage can be as low as 2.8V DC, because the brightness of the LED is proportional to the forward current, so the battery in the portable device must generate a dedicated current source to drive these white LED.

STLD20D is a design of various types of battery voltage in the efficient drive white LED induction boost converter. The battery voltage from 2.8V to DC, it can drive up to 4 LED, and can provide dynamic voltage suppression to prevent the background light jitter. Conversion efficiency greater than 80%. This device includes a LED power switch, reducing standby leakage current soft start function and dimmer controlled shutdown mode STLD20D standby current is less than 1uA, and has over-voltage and over temperature protection function.

The new device has the function of pulse width modulation input, so that white LED can not reduce the bias of dimming, otherwise, this bias can affect the output of color, this feature makes the white LED can maintain the purity of white light throughout the dimming range.

STLD20D using SOT-23 package, different versions of different peak current, this chip also uses 3x3mm QFN package. The price for 100 thousand pieces is $0.45.