Clemens Valens @ elektormagazine.com discuss about LTC3623 switching regulator which can be used as Class-D Audio Amplifier.
Sure thing, Elektor has published several designs of adjustable power supplies based on switching regulators, so we know that doing this properly in a reproducible way and without making things overly complex requires some serious head scratching. The anxiety may be reduced vastly though by a new adjustable synchronous buck regulator which uses a single resistor to set its output voltage anywhere between 0 and 14.5 volts. Using the device is very simple; you can even use it as an audio amplifier.
LTC3623 – Switching regulator doubles as Class-D audio amplifier – [Link]