amplifier

Class D audio amplifier, also named switch amplifier, is used to transform the input analog audio signal or PCM digital information into pulse signal of PWM or PDM, and to control large power switch device to put through/cut off audio power amplifier. The theoretical efficiency of class A audio amplifier is 25％, and its real efficiency is about 15-20％; the theoretical efficiency of class B is about 75％; the theoretical efficiency of class AB is about 75％ as well with a real efficiency between 50％-70％; the theoretical efficiency of class D is about 100％ with a real efficiency of more than 85％. The high efficiency of class D offers lots of advantages, such as power saving, which is quite important for MP3 and music mobile phones. Power saving means longer paying time, and can attract more clients. Another advantage is a smaller heat generation, which can reduce heat management costs. For instance, large power class AB amplifiers usually need radiator, but the as powerful class D amplifiers do not need it.