| 摘要 |
PURPOSE:To improve the accuracy by providing a counter part for generating an output, if a service interruption is continued exceeding a short set time, when a power supply voltage has become a service interruption, and an instantaneous service interruption detecting part for detecting the service interruption by the output of said counter part. CONSTITUTION:A service interruption detecting circuit is provided with a counter part 3 connected to a voltage comparing part 2, and an instantaneous service interruption detecting part 4 which is connected to the counter part 3 and detects a service interruption. In this state, after the time point when an output of the voltage comparing part 2 has become 'L' due to a service interruption, unless it becomes 'H', an output of the counter part 3 becomes 'H', after the time set in advance to a basic clock of the counter part 3 has elapsed. This 'H' signal is applied to the instantaneous service interruption detecting part 4, and the service interruption is detected. In this way, this circuit is provided with a counter part for generating an output to the instantaneous service interruption detecting part, if the service interruption continues exceeding a short set time, therefore, a power supply voltage instantaneous service interruption detecting circuit of a high accuracy is obtained.
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