| 摘要 |
PURPOSE:To prevent the runawy of a microcomputer by supplying a reset signal to the microcomputer securely when a source voltage drops below a specific voltage. CONSTITUTION:When the voltage of a battery power source 1 drops, a voltage V14 divided by voltage-dividing resistances 11 and 12 drops in proportion to the variation. When this voltage V14 drops below a reference voltage V13 determined by a constant-voltage diode 10, the output of a comparing and detecting circuit 8 drops to a low level and a diode 7 which serves as a reverse-current preventing switch turns on. Consequently, a capacitor 6 is discharged speedily through the diode 7 and the reset terminal 4 of the microcomputer 2 is held at the low level. Therefore, the microcomputer 2 is reset. Consequently, the runaway of the microcomputer due to the drop in source voltage is prevented. |
