BRINGING BIG SOUND TO SMALL DEVICES

It's not often that one circuit revolutionizes a huge product category, but the Philips Universal class-D (UcD) module did just that for audio amplifiers. Before the UcD, there had been a few quirky and short-lived commercial class-D amps, which differed from previous amplifiers by using an intermediate stage in which transistors are rapidly switched on and off, versus directly trying to amplify a signal linearly. © 1964-2012 IEEE.