Invention Grant
US08076963B2 Delay-locked loop having a delay independent of input signal duty cycle variation 有权
延迟锁定环路具有独立于输入信号占空比变化的延迟

  • Patent Title: Delay-locked loop having a delay independent of input signal duty cycle variation
  • Patent Title (中): 延迟锁定环路具有独立于输入信号占空比变化的延迟
  • Application No.: US12559749
    Application Date: 2009-09-15
  • Publication No.: US08076963B2
    Publication Date: 2011-12-13
  • Inventor: Xuhao HuangXiaohong Quan
  • Applicant: Xuhao HuangXiaohong Quan
  • Applicant Address: US CA San Diego
  • Assignee: QUALCOMM Incorporated
  • Current Assignee: QUALCOMM Incorporated
  • Current Assignee Address: US CA San Diego
  • Agent Jiayu Xu
  • Main IPC: H03L7/06
  • IPC: H03L7/06
Delay-locked loop having a delay independent of input signal duty cycle variation
Abstract:
A Delay-Locked Loop (DLL) uses a delay line to delay a first signal by a “delay time”, thereby generating a second signal. A capacitor is charged at a first rate starting at a first edge of first signal and continuing until an edge of the second signal. The capacitor is then discharged at a second rate until another edge of the first signal. A control loop controls the delay time such that the amount the capacitor is charged is the same as the amount the capacitor is discharged. The delay time is constant and is substantially independent of variations in the duty cycle of the first signal. In one example, duty cycle distortion cancellation is accomplished by changing the first rate proportionally with respect to changes in first signal duty cycle. In another example, the first and second rates are independent of the duty cycle of the first signal.
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