Charge-Pump and Step-Up DC-DC Converter Solutions for Powering White LEDs in Series or Parallel Connections

Abstract: White LEDs are popular for portable equipment LCD backlights because they are less complex, less expensive, and smaller than CCFL backlights. Portable equipment like PDAs, cellphones, and digital cameras require backlights because they are converting to color LCD displays. This article discusses charge-pump and inductor step-up converter solutions for powering white LEDs in series or parallel configurations. Regulated-voltage or regulated-current controllers are used. Trade-offs in size, efficiency, battery life, and LED-matching are discussed.