TI introduces industry’s first closed-loop PWM-input amplifier power stage
(Top News, 22 Apr 2008 )
Texas Instruments Incorporated has introduced the industry’s first PWM-input 20-Watt stereo Class-D power stage with closed-loop feedback. Extending TI’s portfolio of closed-loop architecture offerings, the highly efficient power stage produces a more accurate sound, improves EMC performance, and relaxes power supply performance requirements to lower system cost. The flexible device supports multiple output configurations and includes a simple PWM interface to a video or audio processor to ease design and speed time to market for manufacturers of LCD, plasma and DLP TVs and media docking stations.
Closing the loop in digital performance while lowering system cost 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. 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 and further lowering 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.
