Date: 26/08/2010

White LED charge pump backlight driver from ADI

Analog Devices has introduced the ADP8870 white LED charge-pump backlight driver that ADI claims lowers the power consumption of battery-operated handheld devices by up to 45 percent without compromising viewing quality. The ADP8870 combines a programmable backlight LED charge-pump driver with inputs for a photo transistor to automatically control the LED brightness and a PWM (pulse-width modulation) input to manage the scale of the output current. This combination of features reduced power use by automatically changing the current intensity based on the ambient lighting levels and the white content of the displayed image.The ADP8870 eliminates the need for a processor to monitor the phototransistor.

"During common operations such as web browsing and email, LED backlighting can account for up to 75 percent of the power used by portable electronics," said Dan Swan, product line director, Power Regulator Products, Analog Devices. "The ADP8870 employs ambient light sensing and content-adaptive backlight control techniques that will extend battery life by optimizing the main and sub display and QWERTY keypad lighting."

The ADP8870 can control up to seven LEDs either grouped together for backlight control or used independently for keypad illumination, indicator lighting or fun lighting1. The fading of each LED is programmable allowing the designer to customize the fade-in, fade-out, dim and off times.

The key features of ADP8870 WLED Backlight Driver include:

--PWM input feature enables content adaptive backlight control
--Photo diode input feature enables automatic ambient light sensing
--Interrupt output feature maximizes power savings by limiting processor involvement
--Programmable lighting transition points and hysteresis are simplified via an I2C-compatible interface
--Sophisticated fading and dimming options enhance media viewing

Availability and Pricing
Product Samples Availability Temperature
Range Price Each
Per 100,000 Packaging
ADP8870 Now now -40°C to+125°C $0.55 20-bump
WLCSP
ADP8870 Now now -40°C to+125°C $0.58 20-lead LFCSP