Patent ID: 6064264
Filing Date: 2000-05-16
Classification: H03F

Abstract:
A switched power amplifier circuit for amplifying an input signal to generate an output signal having adjustable power, comprising:a first MOSFET transistor having a gate, a source, a drain and a backgate and configured so that the input signal is applied to the gate, one of said source and drain is connected to a load having an impedance value, the other of said source and drain is connected to a common terminal, and a control signal is selectively applied to said backgate for simultaneously operating said first MOSFET transistor as a switch and for contributing an inherent impedance value of said first MOSFET transistor to the impedance value of the load for amplifying the input signal; anda second MOSFET transistor having a gate, a source, a drain and a backgate, said second MOSFET transistor being configured so that the input signal is applied to its gate, one of its source and drain is connected to said load, the other of its source and drain is connected to said common terminal, and the control signal is selectively applied to its backgate for simultaneously operating said second MOSFET transistor as a switch and for contributing an inherent impedance value of said second MOSFET transistor to the impedance value of the load for amplifying the input signal;so that when said control signal is applied to one of said first MOSFET transistor backgate terminal and said second MOSFET transistor backgate terminal, the output signal has a first power level, and when said control signal is applied to both of said backgate terminals, the output signal has a second power level higher than said first power level.