| 摘要 |
PURPOSE: A charge pump circuit is provided to improve the current mismatching and to reduce the power consumption by turning off both switches when the up/down signal become high simultaneously. CONSTITUTION: A charge pump circuit includes a charge block(20) and a discharge block(30). In the charge pump circuit the charge block(20) supplies the current to charge the loop filter when the up-signal is high, and it operates so as not to charge the loop filter when the up and the down-signal is high simultaneously. And, the discharge block(30) supplies the current to discharge the loop filter when the down bar signal is low, and it operates so as not to discharge the loop filter when the up bar and the down bar signals become low simultaneously.
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