The MAX1570 fractional charge pump drives up to five white LEDs with regulated constant current for uniform intensity. The MAX1570 maintains the highest possible efficiency over the full 1-cell lithium-ion (Li+) battery input voltage range by utilizing a 1x/1.5x fractional charge pump and very-low-dropout current regulators. The MAX1570 operates with 1MHz fixed-frequency switching, allowing for tiny external components. The regulation scheme is optimized to ensure low EMI and low input ripple. An external resistor sets the full-scale LED current, while two digital inputs control on/off and select between three levels of brightness. A pulse-width modulation (PWM) signal can also be used to modulate LED brightness. The MAX1570 is available in 16-pin 4mm x 4mm Thin QFN packaging (0.8mm max height). Applications * Cell Phones/Smartphones * Digital Cameras and Camcorders * PDAs and Palmtop Computers * Portable MP3 Players * White LED Backlighting * Excellent 0.3% LED-to-LED Current Matching * 30mA/LED Drive Capability * Proprietary 1x/1.5x Modes for Ultra-High Efficiency * Low Input Ripple and EMI * Eliminates Ballast Resistors * Digital or PWM LED Dimming Control * 0.1µA Shutdown Current * 2.7V to 5.5V Supply Voltage Range * Soft-Start Limits Inrush Current * Thermal-Shutdown Protection * No External Inductor, Schottky, or Zener Diode Required * Tiny 16-Pin 4mm x 4mm Thin QFN Package https://elecena.pl/product/22316609/white-led-current-regulator-with-1x-1-5x-high-efficiency-charge-pump 2022-12-27 https://elecena.pl/product/22316609/white-led-current-regulator-with-1x-1-5x-high-efficiency-charge-pump 2025-01-22