Leading light [portable device display illumination]

The need for a white light emitting diode driver to illuminate the displays and keyboards in portable devices has increased rapidly over the last few years. Demand has been fuelled by the market surge in colour displays, especially the active matrix liquid crystal displays found in handheld devices. Although almost every power management business can offer a white light emitting diode (LED) drive, the design engineer has to make the choice between a driver based on a charge pump or boost converter. While obvious reasons may exist for choosing a boost converter, efficiency being one, making the right decision is far from easy.