The Class-D amplifier is one in which the output transistors are operated as switches. When a transistor is off, the current through it is zero. When it is on, the voltage across it is small, ideally zero. In each case, the power dissipation is very low. This increases the efficiency, thus requiring less power from the power supply and smaller heat sinks for the amplifier.

The constant innovation in semiconductor technologies has helped the Class D amplifiers usage due to its higher efficiency (greater than 95%), increased power density and better performance of the amplifier. The highly efficient Class D amplifiers provide similar performance to conventional Class AB amplifiers. Due to Class D amplifiers the size and weight of the power amplifiers is remarkably reduced.

The Class D high power amplifiers uses MOSFET's that are either ON and OFF with respective to time which depend upon type of input analog signal, thus the pulse width modulation (PMW) technique is used to express the analog signal in ON and OFF states in output devices.

The class D high power amplifiers offers some interesting possibilities to even UHF and microwave range frequencies through recent developments in the technology of power amplifiers.

We expertise the use of class D high power amplifiers in RF heating, RF Plasma systems, LASER systems, vibrators (as shown in the figure), high power RF transmitters and other communication systems.