LM27951
Features
- 1 Input Voltage Range: 2.8 V to 5.5 V
- Drives up to Four LEDs With up to 30 m A each
- Regulated Current Sources with 0.2% (Typical)
Matching
- 3/2×, 1× Gain Transition Based on LED Vƒ
- Peak Efficiency Over 85%
- PWM Brightness Control
- Very Small Solution Size
- No Inductor
- Fixed 750-k Hz Switching Frequency
- < 1-µA Shutdown Current
2 Applications
- White LED Display Backlights
- White LED Keypad Backlights
- General Purpose LED Lighting
3 Description
The LM27951 is a switched capacitor white-LED driver capable of driving up to four LEDs with 30 m A through each LED. Its four tightly regulated current sources ensure excellent LED current and brightness matching. LED drive current is programmed by an external sense resistor. The LM27951 operates over an input voltage range from 2.8 V to 5.5 V and requires only four low-cost ceramic capacitors.
The LM27951 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in a...
