| 摘要 |
PURPOSE: A circuit for detecting a low voltage level of a power voltage is provided to improve the accuracy of a low voltage level detection by determining a critical level based on voltages of a diode, a resistor, and a transistor. CONSTITUTION: A time constant adjusting unit(20) adjusts a detecting time of a critical level to be detected from a waveform of an inputted power voltage. The power voltage is applied through a first resistor to perform an on/off operation. An output waveform having an adjusted time constant by the time constant adjusting unit(20) is inputted to an input terminal of a switching device(21). An output terminal of the switching device(21) is connected in serial to a second resistor. An inverter is connected in parallel between the output terminal of the switching device(21) and the second resistor to output the critical level detecting signal of the power voltage by the output of the switching device(21).
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