Patent ID: 8018287

Claim:
An RF power amplifier apparatus comprising: an RF power amplifier; and a power-supply circuit, wherein the power-supply circuit and the RF power amplifier are formed inside a package, wherein the power-supply circuit supplies the RF power amplifier with a source voltage, wherein the power-supply circuit is arranged so as to control a level of the source voltage supplied to the RF power amplifier in response to a level of a power-control signal, wherein the power-supply circuit includes a source-current-sensing circuit for producing a sense signal corresponding to a source current with respect to the source voltage supplied to the RF power amplifier, wherein the power-supply circuit includes a current-control unit for controlling a level of the source current with respect to the source voltage in response to a level of the sense signal produced by the source-current-sensing circuit, and wherein the current-control unit is arranged so as to respond to coincidence of a level of the sense signal produced by the source-current-sensing circuit with an allowable sense signal level corresponding to and allowable level of the source current and control the source current to a limit current set to be smaller than the allowable level of the source current, wherein the current-control unit includes a shutdown switch, wherein the shutdown switch of the current-control unit is controlled into its OFF state in response to coincidence of a level of the sense signal produced by the source-current-sensing circuit with the allowable sense signal level, and wherein the limit current is a shutdown current when the shutdown switch of the current-control unit is in the OFF state.