Invention Grant
- Patent Title: Clock duty cycle recovery circuit
- Patent Title (中): 时钟占空比恢复电路
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Application No.: US11016394Application Date: 2004-12-17
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Publication No.: US07675336B1Publication Date: 2010-03-09
- Inventor: Kok Yoong Foo , Tze Haw Liew , Joo Ming Too
- Applicant: Kok Yoong Foo , Tze Haw Liew , Joo Ming Too
- Applicant Address: US CA San Jose
- Assignee: Altera Corporation
- Current Assignee: Altera Corporation
- Current Assignee Address: US CA San Jose
- Agency: Townsend and Townsend and Crew LLP
- Agent J. Matthew Zigmant
- Main IPC: H03K3/017
- IPC: H03K3/017 ; H03K5/04 ; H03K7/08

Abstract:
Circuits, methods, and apparatus that provide the improvement or recovery of a duty cycle of a clock signal. One embodiment of the present invention receives a clock signal that may have a degraded duty cycle. The frequency of the clock signal is divided by two. The frequency-divided signal is delayed in order to generate two signals that are phase shifted from one another by 90 degrees. These signals are then exclusive-ORed together to generate a recovered clock. A control loop is provided to adjust the phase shift between the signals to be approximately 90 degrees.
Information query
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