Patent ID: 9270230
Filing Date: 2016-02-23
CPC Classification: H03F

Claim Text:
1. A multi-stage amplifier comprising: a first amplifier stage; a second amplifier stage; and a voltage supply stage arranged to provide a supply voltage to the first amplifier stage in dependence on an average power of a signal to be amplified and a supply voltage to the second amplifier stage in dependence on an instantaneous power of the signal to be amplified, wherein there is provided an average supply determination block for determining the average of the supply generated by the supply voltage stage, and providing the supply voltage to the first amplifier stage in dependence upon the determined average, wherein the voltage supply stage is arranged to selectively provide supply voltages to the first and second amplifier stages, wherein in a first mode of operation the signal is amplified by the first and second amplifier stages, and the supply voltage stage is selected to provide a supply voltage to the first amplifier stage in dependence on the average power of the signal to be amplified and the second amplifier stage in dependence on the instantaneous power of the signal to be amplified, and in a second mode of operation the second amplifier stage is bypassed, the signal being amplified by the first amplifier stage, and the supply voltage stage is selected to provide a supply voltage to the first amplifier stage in dependence on the instantaneous power of the signal to be amplified.