White LED Charge Pump
Maxim introduces the MAX1574 LED charge pump that requires one transfer capacitor for simple implementation. Packaged in a 3 × 3 mm TDFN, this device is a solution for cell phones and other handheld devices. The charge pump drives up to three parallel white LEDs with a regulated, constant current for uniform intensity. By utilizing adaptive 1x/2x modes and low-dropout current regulators, it achieves up to 92% peak efficiency or 83% average efficiency over the full 1-cell Lithium-ion (Li+) battery input-voltage range. It provides 0.6% current matching for uniform backlighting of color LCD displays. The device's output current (up to 180 mA) permits use in camera strobes/flashes, movie lights, and keyboard backlight applications. The product features a single-wire, serial-pulse interface for dimming down to 5% of peak, soft-start to limit inrush current, overvoltage protection, thermal shutdown, and complete input-to-output disconnect during shutdown (0.1 microamp shutdown current). The input voltage range is 2.7 to 5.5 V.
Maxim Integrated Products