Cutting power consumption

Designed to extend playback time for audio enabled portable devices, such as portable media players, multimedia handsets and handheld gaming systems, the WM8903 is said to enables designers to push product design boundaries and develop differentiated end products. “We’ve been talking about power consumption and package size for some time,” said Eric Haber, product architect. “The 8903 goes in the same direction, but in a new way.” He added the device featured ‘technology breakthroughs’ and the ability to reduce the number of external components. Using a multimedia phone as an example, Haber claimed a typical operating time was up to 24 hours from an 1100mAh battery. “With the 8903 and the latest application processor, this can be increased to 120hr from the same battery. It’s not all down to the 8903, but it makes a big contribution.” The device features Wolfson’s Class W amplifier technology, an evolution of class G/H, featuring an adaptive dual drive charge pump and dc servo circuit architecture. Class W technology tracks the music signal level and uses an adaptive dual drive charge pump to optimise power dissipation. “Blending capless operation with low power is hard,” said Haber, “but we’ve done it with Class W.” Also features is Wolfson’s SmartDAC technology, described by Haber as a technique to save power without impacting audio quality. SmartDAC reduces headphone power consumption to 4.4mW and includes a capability for programmable ‘performance vs power’ profiles. Haber noted the WM8903 is the first device in a new range of parts to be based on this technology. “You can expect to see Class W and SmartDAC technologies in future products,” he concluded.