Amplifying circuit, speaker system, and mobile information terminal employing amplifying circuit

摘要

A power supply system supplies a power to a CPU with a power saving mode to a mobile information device or terminal. The power supply system includes a power supplying circuit for supplying the CPU with a prescribed supply voltage, a voltage detecting circuit for outputting a reset signal resetting the CPU when the supply voltage decreases to be less than or equal to a prescribed reset level, and a control circuit for decreasing the supply voltage to a prescribed power save level when the power saving mode is set. The control circuit decreases the supply voltage to be the prescribed power save level after decreasing the prescribed reset level to be less than or equal to the power save level when the power saving mode is set. The control circuit recovers the prescribed reset level after recovering the supply voltage when the power saving mode is terminated.