| 摘要 |
PROBLEM TO BE SOLVED: To provide a portable terminal whose battery service life can be extended. SOLUTION: A standby function controller 303 controls a power source for a block oscillation circuit 305, a peripheral circuit 307 and an ALU 309 included in the portable terminal TAG. The standby function controller 303 controls the power source for the circuits 305, 307, 309 so as to select a mode where all the power sources are energized, a mode where all the power sources are de-energized or a mode where the power source of the clock oscillation circuit 305 is energized and the power sources of the other circuits are de-energized. Energizing only the clock oscillation circuit 305 and de-energizing the other circuits reduce the entire power consumption. Furthermore, a standby time up to stable oscillation required when the clock oscillation circuit is activated from an inactive state is eliminated. |
