发明授权
- 专利标题: Loop circuitry with low-pass noise filter
- 专利标题(中): 具有低通噪声滤波器的回路电路
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申请号: US10759915申请日: 2004-01-16
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公开(公告)号: US07002384B1公开(公告)日: 2006-02-21
- 发明人: Yan Chong , Joseph Huang , Chiakang Sung , Philip Pan , Tzung-chin Chang
- 申请人: Yan Chong , Joseph Huang , Chiakang Sung , Philip Pan , Tzung-chin Chang
- 申请人地址: US CA San Jose
- 专利权人: Altera Corporation
- 当前专利权人: Altera Corporation
- 当前专利权人地址: US CA San Jose
- 代理机构: Fish & Neave IP Group of Ropes & Gray LLP
- 代理商 Robert R. Jackson; Hong S. Lin
- 主分类号: H03K5/13
- IPC分类号: H03K5/13 ; H03D3/24
摘要:
Phase comparators for use in loop circuits (i.e., DLL circuits and PLL circuits) are provided. The phase comparators include a phase detector for comparing a reference clock signal and a feedback signal derived from the loop circuit generated internal clock signal. The phase comparators also include a low-pass noise filter for filtering out erroneously detected phase differences between the reference clock signal and the feedback signal by requiring a certain net number of leading or lagging detections before the compensation circuitry of the loop circuit (i.e., the controlled delay line in a DLL circuit or the controlled oscillator in a PLL circuit) is adjusted. The number of net measurements required before these adjustments take place depends on a programmable bandwidth signal provided to the phase comparator.