BL8545
REV1.
0-Revised SEP 2008
High Efficiency Low Noise PFM Step-up DC/DC Converter
DESCRIPTION
The BL8545 PFM step-up Converter drives white LEDs with a constant current to provide backlight in cell phones, PDAs, and other handheld devices.
It features allowing series connection of the white LEDs so that the LED currents are identical for uniform brightness.
An enable input can be pulsed repeatedly to adjust LEDs brightness.
The fast 500KHz to 2MHz operation frequency allows for smaller capacitor and inductor.
Fault condition protection uses cycle-by cycle current limiting to sense maximum inductor current and over-
voltage protection.
The 0.
2V low reference
voltage minimized the power lo...