Patent ID: 8089253

Claim:
A method, comprising: measuring a battery voltage inputted to a cascade connection of a boost-type switched-mode power supply and a buck-type switched-mode power supply providing a supply voltage to a radio frequency power amplifier, wherein at least one of the buck-type switched-mode power supply and the boost-type switched-mode power supply comprises at least two section modes having at least two parallel switches such that in a first one of the section modes both of the two parallel switches are switched on and off at the switching frequency to provide a maximum load current to the radio frequency power amplifier, and in a second one of the section modes a first one of the parallel switches is switched on and off at the switching frequency; comparing the measured battery voltage with a threshold corresponding to an input supply voltage which is needed for the buck-type switched-mode power supply; bypassing the boost-type switched-mode power supply and coupling the battery voltage directly to the buck-type switched-mode power supply, if the measured battery voltage exceeds the needed input supply voltage; controlling the boost-type switched-mode power supply to raise the battery voltage to at least the needed input supply voltage, if the measured battery voltage is below the needed input supply voltage; and controlling the buck-type switched-mode power supply to operate in one of at least two section modes according to one or more of the following: a mode of operation of the power amplifier, a frequency band of the power amplifier, a modulation method, and a transmission power of the power amplifier.