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Title:
SPREAD SPECTRUM CLOCK CONTROL DEVICE AND SPREAD SPECTRUM CLOCK GENERATION DEVICE
Document Type and Number:
Japanese Patent JP2007233968
Kind Code:
A
Abstract:

To provide a device that can ON/OFF-control an SSC (spread spectrum clock) function and can implement a smooth ON/OFF transition of the SSC function without any transient frequency changes.

A control circuit 3 for generating a phase control signal for variable phase control to a phase interpolator 4 for inputting an input clock signal and changing the phase of an output clock signal according to the phase control signal comprises a count operation control circuit 31 for outputting a count operation control signal for controlling the stop of a count operation. The count operation control circuit 31 inputs count values 26 and 27 of counters 22 and 23, and sets the count operation control signal 32 at a value representing a count stop when a control signal supplied from an SSC control terminal 8 represents a stop and both count values 26 and 27 of the counters 22 and 23 are an initial value (=0).

COPYRIGHT: (C)2007,JPO&INPIT


Inventors:
NAKAHIRA MASAO
Application Number:
JP2006058304A
Publication Date:
September 13, 2007
Filing Date:
March 03, 2006
Export Citation:
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Assignee:
NEC ELECTRONICS CORP
International Classes:
G06F1/06; G06F1/04; H03K23/00
Domestic Patent References:
JP2005004451A2005-01-06
JP2001160788A2001-06-12
JP2001092311A2001-04-06
JP2002073199A2002-03-12
JP2005004451A2005-01-06
JP2001160788A2001-06-12
JP2001092311A2001-04-06
JP2002073199A2002-03-12
Attorney, Agent or Firm:
加藤 朝道



 
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