Patent ID: 7671682

Claim:
A variable gain power amplifier, comprising: a power amplifying unit including a control terminal through which a control signal that varies a gain of said power amplifying unit is provided; and a signal generating unit that generates said control signal to be provided to said control terminal, wherein said signal generating unit comprises: a current mirror circuit, a constant current source that generates a constant current, and a variable current source that generates a variable current; said variable current source comprises a variable resistance element; said signal generating unit generates said control signal of a magnitude that turns on said power amplifying unit; said control signal is a mirror current generated by said current mirror circuit based on a reference current of said current mirror circuit; and said reference current of said mirror circuit is the sum of a positive current generated by said constant current source and a positive current generated by said variable current source; and a magnitude of said positive current generated by said variable current source is controlled by said variable resistance element.