The TPS60231 charge pump is optimized for white LED supplies in color display backlight applications. The device provides a constant current for each LED, which the initial value can be set by an external resistor. The supply voltage ranges from 2.7 V to 6.5 V and is ideally suited for all applications powered by a single LI-Ion battery cell or three to four NiCd, NiMH, or alkaline battery cells. Over an input voltage range from 3.1 V to 6.5 V, the device provides a high output current of up to 25 mA per LED with a total of 75 mA. High efficiency is achieved by utilizing a 1x/1.5x fractional conversion technique in combination with very low dropout current sources. In addition, the current controlled charge pump ensures low input current ripple and EMI. Only two external 1 µF and two 0.47 µF capacitors are required to build a complete small and low cost power supply solution. To reduce board space to a minimum, the device switches at 1 MHz operating frequency and is available in a small 16-pin QFN (RGT) package.

• Regulated Output Current With 0.4% Matching
• Drives up to 3 LEDs at 25 mA Each
• LED Brightness Control Through PWM Control Signal
• High Efficiency by Fractional Conversion With 1x and 1.5x Modes
• 1 MHz Switching Frequency
• 2.7 V to 6.5 V Operating Input Voltage Range
• Internal Softstart Limits Inrush Current
• Low Input Ripple and Low EMI
• Overcurrent and Overtemperature Protected
• Undervoltage Lockout With Hysteresis
• Ultra-Small 3mm x 3mm QFN Package
• APPLICATIONS
  • White LED Backlight for Color Displays in Cellular Phones, Smart Phones, PDAs, Handheld PCs, Digital Cameras, and Camcorders
  • Keypad Backlight