Patent ID: 7183856
Filing Date: 2007-02-27
Classification: H03G

Abstract:
1. The power source circuit for a high frequency power amplifying circuit which supplies a power source voltage to the high frequency power amplifying circuit, comprising: a first direct current power source circuit constructed by a series regulator or a shunt regulator; and a second direct current power source circuit constructed by a switching regulator, wherein the first and second direct current power source circuits being provided in parallel with a voltage output terminal, and a power source terminal being connected to the voltage output terminal, wherein at the time of changing the power source voltage supplied to said high frequency power amplifying circuit in order to change output power of said high frequency power amplifying circuit, both of said first and second direct current power source circuits are started and, after lapse of predetermined time or after the output power source voltage reaches a predetermined level, an operation of said first direct current power source circuit is stopped or power supply capability is lowered, wherein said first direct current power source circuit comprises a transistor in which a channel between a source and a drain is connected between a voltage input terminal and a voltage output terminal or between the voltage output terminal and a ground point, and a differential amplifier connected to a gate terminal of the transistor, and wherein a voltage according to the output power source voltage is fed back to one of input terminals of said differential amplifier, a reference voltage can be applied to the other input terminal of said differential amplifier, and said transistor is operated according to an output of said differential amplifier.