发明名称 |
Compensator for leakage through loop filter capacitors in phase-locked loops |
摘要 |
A loop filter of a compensating phase-locked loop contains capacitors formed from transistors with thin gate oxide dielectric layers. Leakage current leaks through the capacitors. To avoid jitter in the output signal of the phase-locked loop that would otherwise be caused by the leakage current, a leakage compensation circuit is provided. The leakage compensation circuit of a first embodiment replicates the leakage current using a replication capacitor and a current mirror. The voltage across the replication capacitor is proportional to the control voltage of a voltage-controlled oscillator of the compensating phase-locked loop. A second embodiment generates the compensation current by controlling the voltage on the gate of a transistor. The gate voltage depends on charge added and subtracted by a charge pump in addition to the charge pumps in the loop filter. A third embodiment applies a leakage compensation circuit to a delay locked loop.
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申请公布号 |
US2005035797(A1) |
申请公布日期 |
2005.02.17 |
申请号 |
US20030638717 |
申请日期 |
2003.08.11 |
申请人 |
RAMBUS, INC. |
发明人 |
FRANS YOHAN;NGUYEN NHAT M. |
分类号 |
H03L7/081;H03L7/089;H03L7/093;(IPC1-7):H03L7/06 |
主分类号 |
H03L7/081 |
代理机构 |
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主权项 |
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地址 |
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