| 摘要 |
PURPOSE:To minimize an increase in a chip area and to reduce costs by providing a chip with an input port for monitoring a power source voltage, periodically checking whether the voltage of the input port drops below a threshold level or not and moving to a low power consumption mode when the voltage drops. CONSTITUTION:The forming device has a controller 1 (chip), a power source voltage monitoring port 2, and a power source terminal 3. Here, a time constant when output voltages from voltage generating means 5 to 7 drop is set far lower than that when an output voltage from a power source device drops. The power source voltage monitoring port 2 is handled not as an interruption input but as merely an input port. Software periodically checks, and when a voltage drop is detected, the current operation is immediately shifted to the lower power consumption mode. Consequently, no dedicated interrupter, etc., for the shift is needed to minimize an increase in the chip area, thereby reducing costs. |
