Design of a linearly assisted switcher for a supply modulated RF transmitter

Abstract

A broadband modulated power supply for envelope tracking or polar RF transmitters has been built. To study the design constraints, an efficient state-based simulation tool was developed. Based on the simulations, a prototype supply was built. It can deliver up to 1 W (6 V, 150 mA) to a resistive load of 30 ohms with spectral purity of ca. -45 dBc. The power efficiency using a QAM-signal is 49%.