Audio amps claim to be 20x better than Class D

Audium Semiconductor claims that the company's new audio power amplifier is 20x more efficient than Class D amplifiers at normal listening levels. The AS1001 operates from 1.5V power supply and delivers 100W peak power output. Battery-powered loudspeakers equipped with the amplifier can run for up to 10 months on a set of four 'C' batteries, playing for three hours per day, according to the company. This reduces CO₂ from power generation and pollution from battery production.

The amplifier also enables the development of smaller, cooler, mains-powered audio equipment, with fewer heat sinks. Applications include totally wireless speakers, home theatre surround sound speakers and battery-powered travel speakers. Future Audium ICs will support MP3 docking stations and USB powered speakers.

The AS1001 architecture uses patented techniques to minimise both fixed power losses and output-dependant variable power losses. The modulation scheme uses low switching rates to minimise switching losses. Power rail switching means that the amplifier operates efficiently from a low voltage rail most of the time, with a DC/DC boost converter driving higher voltage transistors on extreme audio peaks.

"Traditionally, audio amplifiers have only reached quoted efficiency figures at maximum output, which is like building a city-car that's only efficient at 200mph and anything but efficient at 30," said Huw Davies, chief commercial officer, Audium. "The AS1001 marks a huge leap forward in efficiency and has come from examining how equipment is really used rather than striving for a marketable arbitrary figure."

"Over 700 million (70 crore) consumer audio devices are sold each year, so the real world efficiency of these has a huge impact on the amount of energy we consume," commented Malcolm Penn, CEO, Future Horizon. "Looking beyond the environmental implications, the technology behind the AS1001 will enable a whole new class of low power consumer products."

Targeting battery powered applications; the AS1001 is a single 64QFN package and operates directly from a 0.8- to 1.8V supply (compatible with, for example, alkaline primary cells and Ni-MH secondary cells). Samples are available now, priced from Rs.388.92 ($8) each in 1,000+ quantities.