| 摘要 |
PURPOSE:To reduce the power consumption by performing a comparation work only when a working instruction like a loading instruction, etc., is delivered to a comparator from a microprocessor. CONSTITUTION:An input circuit of a microprocessor produces a control signal via a control signal generating circuit 4 after input of a working instruction. This control signal is outputted for a fixed time to a gate circuit 2 which transmits the clock signal used for a comparator 1. Thus the circuit 2 opens a gate for a fixed period of time. As a result, plural types of clock signals for comparators are supplied to a comparator 2. The comparator 2 samples the input voltage Vim to compare it with the reference voltage Vref and outputs a binarized signal in response to the result of said comparison. That is, the comparator 2 performs the comparation work only when a working instruction like a loading instruction, etc., is delivered from the microprocessor. As a result, the power consumption is reduced compared with a case where the clock signal is always needed for working.
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