| 摘要 |
PURPOSE:To generate surely a reset signal by comparing an output voltage with the 1st reference voltage so as to drive a discharge circuit and comparing the output voltage with the 2nd reference voltage so as to drive a charging circuit having a short charging time constant. CONSTITUTION:When power is applied, an output of the 1st and 2nd comparator circuit 28 is at a low level. When an output voltage of a constant voltage circuit 10 is high and larger than the 2nd reference value, the output of the 2nd comparator circuit goes to a high level, the discharge transistor 23 is turned off to start charging. When the output voltage reaches the 1st reference value or over, the output of the 1st comparator circuit goes to a high level and the 2nd charging circuit having a short charging time constant is activated. The converse operations are proceeded at power interruption. |
