portable power supply-Bringing high performance speaker

Bringing high performance speaker driver functionality and dramatically extended playback to mobile internet devices, handheld gaming and portable media players.
Edinburgh, UK - 22nd June 2009 - Wolfson Microelectronics (LSE: WLF.L) today announces the WM8961 ultra low power stereo CODEC - the second product from its new family of next generation ultra low power devices designed to dramatically extend playback time for audio enabled portable devices. The WM8961 builds on the foundation of Wolfson's ground-breaking WM8903 CODEC, packing in the same innovative technology along with an additional integrated high power Class D stereo speaker driver. This enhancement extends Wolfson's industry-leading ultra low power audio technology into applications that require high performance speaker driver functionality, including mobile internet devices (MID), handheld gaming and portable media players (PMP).
Delivering Wolfson's renowned high performance audio in both playback and record applications, the WM8961 provides the industry's lowest playback power enabling dramatically extended battery life in the demanding real usage modes of today's multimedia portable devices. This is coupled with an ultra slim, low profile form factor package and small total solution footprint which gives the designers of today's multimedia portable devices the freedom to push design boundaries and develop compelling and highly differentiated end products.
The WM8961 provides the core for an ultraportable power supply low power audio subsystem, seamlessly connecting microphones, such as Wolfson True Mics technology, line inputs, FM tuners, cellular baseband, speakers and headphones. It also enables significant savings in PCB space and the audio subsystem bill of materials (BOM) while significantly reducing time to market by lowering software development time.
Duncan Macadie, low power audio Product Line Manager at Wolfson comments, "Packed with innovative ultra low power technologies, which ensure absolutely no compromise to audio quality, the WM8961 is an important addition to Wolfson's highly successful next generation ultra low power portfolio. The WM8961 has been carefully designed to balance high performance audio with ultra low power consumption, whilst the high level of integration and configurability ensure that system design complexity is reduced, and bill of materials cost is minimised. The WM8961 extends Wolfson's next generation ultra low power technology into applications, which require high performance speaker driver functionality and dramatically extended playback time."
The WM8961's integrated charge pump provides a ground-referenced output when driving headphone loads. This removes the need for DC-blocking capacitors and enables portable power supplysignificant savings in PCB space and the audio subsystem bill of materials (BOM). The WM8961 also uses Wolfson's proprietary Class W amplifier technology - an evolution of class G/H, featuring an adaptive dual drive charge pump and DC servo circuit architecture - to intelligently optimise efficiency and power consumption during playback and enable the headphone amplifier to deliver up to 30mW into a 16W load at 1% THD+N.
The WM8961's stereo filter-less class D speaker driver provides 1W per channel into 8W loads at <1% THD+N with a 5V supply. Low leakage, an excellent power supply rejection ratio (PSRR) portable power supplyand pop/click suppression mechanisms also allow direct battery connection to the speaker supply. Flexible speaker boost settings allow speaker output power to be maximised while minimising other analogue supply currents.
Use of an integrated control sequencer enables the WM8961 to reduce 'pops & clicks' significantly and reduces time to market by lowering software driver development time. Wolfson has also integrated its innovative SilentSwitch(TM) technology in the WM8961 to further enhance its 'pop & click' suppression capability, portable power supplyby incorporating sophisticated clamp and sequencer circuitry. Unwanted noise at the headphone amplifier output is reduced during power-up and mute/un-mute by clamping the output to ground, while an advanced automatic level controller is incorporated on the WM8961 to optimise recorded sound quality.