| 摘要 |
PURPOSE:To generate a proper reset signal without the complexity of a circuit which generates an initial reset signal to an electronic circuit on the basis of the detection result nor an increase in cost by detecting the potential difference between the output voltage of a voltage stabilizing circuit which supplies an operating voltage to the electronic circuit and the input voltage to the voltage stabilizing circuit. CONSTITUTION:If a power source 1 has a momentary power failure, the input voltage Vo drops and then the operating voltage Vd also drops. When the operating voltage Vd drops below an operable voltage level Vb, a microcomputer 20 stops operating and a series of processes are interrupted. At this time, the operating voltage Vb is nearly equal in level with the input voltage Vo and its potential is lower than a specific value, so the transistor (TR) 11 of a reset signal generating circuit 10 turns off. When the TR 11 turns off, the reset signal Vr goes to logic 0 as mentioned above and the storage element in the microcomputer 20 is initialized. Consequently, the proper reset signal is generated without the complexity of the circuit nor an increase in cost. |
