This document introduces the features and characteristics of the ADM8843 four white LED backlight driver. The driver uses charge pump technology to provide power to drive up to four LEDs. The LEDs are used for backlighting a color LCD display that has regulated constant current for uniform brightness in the entire brightness range.
The ADM8843 is a four‑white‑LED backlight driver designed for cellular phones, camera flash, and other display applications. It uses a charge‑pump architecture that automatically switches between 1x, 1.5x and 2x modes to maintain high efficiency across a 2.6 V‑5.5 V input range. Digital inputs CTRL1 and CTRL2 provide shutdown control and individual brightness adjustment for main and sub displays.
Key features include up to 88 % power efficiency, 0.3 % typical LED current matching, low‑power shutdown mode, and a compact 3 mm × 3 mm LFCSP package. The device supports PWM dimming from 0.1 kHz to 200 kHz and provides a soft‑start to limit in‑rush current.
| Input Voltage Range | 2.6 V to 5.5 V |
|---|---|
| Supply Current (all LEDs disabled) | 2.6 mA to 5 mA |
| Charge Pump Frequency | 15 MHz |
| LED Current Matching Accuracy | 0.3 % |
| Shutdown Current | 5 µA |
| LED Drive Current | 20 mA per LED |
| PWM Frequency Range | 0.1 kHz – 200 kHz |
| Input High Voltage Level | 0.7 V |
| Input Low Voltage Level | 0.3 V |
The device operates from 2.6 V to 5.5 V input voltage.
It can drive up to four white LEDs, with separate control for a main and a sub display.
The LED current matching accuracy is typically 0.3 %.
The driver can achieve up to 88 % power efficiency over the Li‑ion voltage range.