PHASE-LOCKED LOOP CIRCUIT
PROBLEM TO BE SOLVED: To lose transistor current in a charge pump and reduce power consumption by providing a phase comparator with a power cut signal input terminal and forcibly making a Down pulse and an Up pulse, which are outputted from the phase comparator when a power cut signal is inputted to...
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Format: | Patent |
Sprache: | eng |
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Zusammenfassung: | PROBLEM TO BE SOLVED: To lose transistor current in a charge pump and reduce power consumption by providing a phase comparator with a power cut signal input terminal and forcibly making a Down pulse and an Up pulse, which are outputted from the phase comparator when a power cut signal is inputted to each logic L and H. SOLUTION: A phase comparator 110 outputs a Down pulse and an Up pulse, according to the phase difference between an inputted reference clock CLK and a feedback clock FB. A voltage control oscillator 140 outputs a frequency that corresponds to output voltage of a loop filter 130, which is charged and discharged by a charge pump 120 according to the pulse output. The comparator 110 forcibly makes a Down pulse and an Up pulse, which are outputted logic L and logic H respectively when a power cut signal PC is inputted. Thereby, when the oscillator 140 is in a power cut state, power consumption is reduced by making the charge pump power cut. |
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