| 摘要 |
PROBLEM TO BE SOLVED: To obtain a clocked comparator which is capable of a high-speed operation and prevents a consumption current from depending on a power-supply voltage by adjusting the supply current of a variable current source. SOLUTION: A consumption current is decided by a supply current i0 of a variable current source 31 when a switch control signalϕ1 is on a high level, that current becomes maximum when a switch control signalϕ2 is on a high level is at the time when Vin=Vref, and the current is the same as a consumption current when the signalϕ1 is on the high level. This is decided by the variable current source 31 and is not changed by the fluctuation of a power supply voltage. Further, it is possible to optimize power consumption when the current is set to a minimum value needed to achieve a requested operation speed by adjusting the supply current i0 of the variable current source 31. Further, an operation becomes fast because both a P type MOSFET 15 and an N type MOSFET 17 contribute to Vout fluctuations.
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