| 摘要 |
PROBLEM TO BE SOLVED: To realize cost reduction by switching main and sub-power supplies depending on the voltage rise or drop of main power supply and interrupting or operating a system controller thereby decreasing the number of chips constituting a power supply controller. SOLUTION: When a voltage detection means 201 detects voltage drop of a main power supply VBB below a predetermined level, a system controller is notified the fact. Switching means Q1, Q2 then switch the main power supply VBB to a sub-power supply BAT 1 and a reset signal is outputted upon receiving a signal indicative of the state where the system controller can be reset thus stopping the system controller. When the voltage detection means 201 detects voltage rise of main power supply VBB over a predetermined level, the switching means Q1, Q2 switch the sub-power supply BAT 1 to main power supply VBB and outputs a reset release signal to operate the system controller. When the main power supply VBB is normal, a reset signal is outputted. |
