Patent ID: 7518451
Filing Date: 2009-04-14
Classification: H03F

Abstract:
1. A switch mode power amplifier for higher frequency applications comprising: a) a transistor having a first terminal, a second terminal, and a control terminal and having internal capacitance between the first terminal and second terminal, b) a signal input terminal coupled to the control terminal, c) a power terminal coupled to the second terminal through an inductance, d) a ground terminal coupled to the first terminal, and e) a resonant circuit coupling the second terminal to an output terminal, whereby an input signal at the signal input terminal controls conduction of the transistor between the first terminal and the second terminal, so that when the transistor is conducting, the second terminal is coupled to ground and current from a power source to the second terminal increases; wherein when the transistor is turned off, current from the power source is steered into the internal capacitance of the transistor and causes voltage on the second terminal to rise to an increased value and then decrease; wherein the voltage at the second terminal is coupled to the output terminal through the resonant circuit; and wherein the transistor comprises a compound semiconductor field effect transistor with the first terminal being a source terminal and the second terminal being a drain terminal, the transistor comprising: a substrate, a channel layer on the substrate, and a barrier layer on the channel layer.