Class-D amp enhances flat screen TV sound quality

San Jose, Calif. — This Class-D amplifier for flat screen TVs from Royal Philips Electronics drives 20 watts of continuous output power per channel with no external heat sink.

This feature is a key parameter for flat TVs — simplifying design and reducing component count, total system cost and space requirements for flat TVs, said Jan-Paul Huyser, international product marketing of audio amplifiers at Philips Semiconductors. High efficiency eliminates the need for a heat sink — up to 20 W rms, Huyser added.

Additional applications for the device include flat panel monitors, multimedia systems, wireless speakers and micro systems.

The device is a switching power stage for high efficiency class-D audio power amplifier
systems. It contains a single-ended power stage, drive logic, protection control logic, a full
differential input comparator and a high-voltage pack (HVP) charger to charge the singled-ended capacitor. With this amplifier a compact 1 x 20-W closed loop self-oscillating digital amplifier system can be built. A second order low-pass filter converts the pulse-width modulation (PWM) output signal into an analog audio signal across the speaker. The system operates on an asymmetrical and a symmetrical supply voltage.

The amplifier also boasts lower electromagnetic interference (EMI) than other solutions on the market and eliminates the audible pop when switching the system on and off, according to Huyser.

Philips' TDA8931T is available now in a SO20 (SOT163-1 version) package, and sells for 90 cents each in 100,000-piece quantities. Click here for the TDA8931 prelim data sheet.

Philips Semiconductors , 1-800-447-1500,

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