Patent ID: 7269447

Claim:
A portable telephone terminal having a load portion and operable to receive a battery unit for supplying operating power, where power consumption varies according to a status of operation of the portable telephone terminal, said portable telephone terminal comprising: a first power supply circuit arranged so as to be connectable to said battery unit and operable to convert a voltage of said battery unit; a second power supply circuit arranged so as to be connectable to said battery unit and operable to convert the voltage of said battery unit; a determining circuit for determining said status of operation of the portable telephone terminal; and a control circuit for effecting control according to said determined status of operation to switch between a first power supply mode wherein said first power supply circuit supplies power to said load portion and a second power supply mode where said second power supply circuit supplies power to said load portion, wherein said control circuit stops a supply of power from said first power supply circuit when a specified time has passed after starting said second power supply circuit.