A power saving device for a radio communication terminal reduces current
consumption by changing the number of power amplifying stages. A power
amplifier in the radio communication terminal includes a first amplifier
for high power and a second amplifier for low power. A signal path
selector switches an input signal to an input node of the first or second
amplifier in response to a switching control signal. An output path
selector selects one of output signals from the first and second
amplifiers in response to the switching control signal. An RSSI detector
detects signal strength of a signal received from a base station. A
controller generates the switching control signal of a first state, when
the signal strength is low, to enable the signal path selector to switch
the input signal to the first amplifier and enable the output path
selector to select the output signal of the first amplifier, and generates
the switching control signal of a second state, when the signal strength
is high, to enable the signal path selector to switch the input signal to
the second amplifier and enable the output path selector to select the
output signal of the second amplifier. A power supply blocks a first
supply voltage to the first amplifier in response to the switching control
signal of the second state, and blocks a second supply voltage to the
second amplifier in response to the switching control signal of the first
state.