| 摘要 |
PROBLEM TO BE SOLVED: To generate a pulse signal having fixed pulse width independently of power voltage by charging a capacitor with a constant current responding to a control signal, comparing charged voltage in the capacitor with reference voltage, and outputting a pulse signal based on the compared result. SOLUTION: A switch circuit 13 is turned ON when an input signal IN is H level. After the input signal IN becomes L level and the switch circuit 13 is turned OFF, a capacitor 12 is charged with a constant current. Charged voltage in the capacitor 12 is compared with reference voltage Vref, the compared result is reversed by an inverter 16, and an output signal OUT is obtained. As an output current value from a constant current source circuit 14 is always constant independently of a value of power source voltage VDD, charged voltage of the capacitor 12 exceeds reference voltage Vref after a fixed time whenever an input signal IN is supplied, a pulse signal OUT of fixed pulse width is outputted from the inverter 16.
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