Class-D power stage improves audio performance in HDTVs

Dallas, Tex. — Texas Instruments Inc. (TI) has introduced a PWM-input 20-watt stereo Class-D power stage with closed-loop feedback, aimed at HDTVs and media docking stations. Touted as the industry's first, the highly efficient power stage is said to produce a more accurate sound and improve EMC performance. The TAS5601 device also relaxes power supply performance requirements to lower system cost, TI said.

Improving audio performance, the closed loop architecture of the TAS5601 enables the audio subsystem greater control over the speaker, reproducing a more accurate sound with improved bass response. The superior power supply rejection ratio (PSRR) of closed loop architectures reduces power supply noise coupling into the audio band, allowing engineers to design lower cost power supplies, TI said. The EMC performance is also greatly improved by slowing down the output edge transitions while still maintaining excellent THD+N.

The TAS5601 is more than 90 percent efficient and requires only two supplies, a 3.3 V and 10-V to 26-V rail. Supporting operation up to +26 V allows LCD-TV manufacturers to power the device off the existing +24-V backlight rail, eliminating the need for a dedicated audio power rail, which further reduces system cost.

In addition, the TAS5601 is fully protected with integrated self-protection circuits against faults including over-voltage, under-voltage, over-temperature and short circuit. Short-circuit faults and thermal warnings are reported back to the system controller.

The flexible platform of the TAS5601 supports multiple output configurations for driving two bridge-tied speakers, four single-ended speakers, or a combination of single and bridge-tied speakers for 2.1 system support. The TAS5601 also includes a simple PWM interface to a video processor or a digital audio processor such as TI's recently introduced TAS3308 audio System on a Chip (SoC).

Pricing: Available in a 56-pin HTTSOP package, the TAS5601 is priced at $2.00 in 1000-piece quantities.
Product information: TAS5601, TAS3308, and Audio solutions guide

Texas Instruments Inc. , 1-800-477-8924,

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