Invention Grant
- Patent Title: Structure for precision integrated phase lock loop circuit loop filter
- Patent Title (中): 精密集成锁相环电路环路滤波器结构
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Application No.: US12129514Application Date: 2008-05-29
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Publication No.: US07692460B2Publication Date: 2010-04-06
- Inventor: David William Boerstler , Jieming Qi
- Applicant: David William Boerstler , Jieming Qi
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Yee & Associates, P.C.
- Agent Matthew B. Talpis
- Main IPC: H03L7/06
- IPC: H03L7/06

Abstract:
A design structure for a loop filter in a phase lock loop circuit comprising a reference precision resistor, a first and second FET, wherein the gate of the first FET is tied to the gate of the second FET, and a filter capacitor connected to the first FET for producing a capacitor voltage. The capacitor voltage is applied to the source of the first FET, the source of the second FET, and the bottom of the reference precision resistor acting as a virtual ground. The capacitor voltage generated by the filter capacitor sets the bias point of the second FET such that the second FET comprises characteristics of an integrated precision resistor. A predetermined voltage generated by the second FET is applied to the gate of the first FET to set the bias point of the first FET such that the first FET comprises characteristics of an integrated precision resistor.
Public/Granted literature
- US20090108923A1 Structure for Precision Integrated Phase Lock Loop Circuit Loop Filter Public/Granted day:2009-04-30
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