发明名称 |
Clock signal generation circuit capable of operating at high speed with high frequency |
摘要 |
A clock signal generation circuit performs a stable operation with respect to both a high frequency input clock signal and a sufficient low frequency testing clock signal. The circuit includes a phase comparator for generating a phase difference output corresponding to a phase difference between an internal clock signal and a reference clock signal externally supplied; a frequency distinction circuit for generating a frequency change-over signal when a frequency of the reference clock signal is lower than a preset reference signal; a loop filter for generating an output voltage corresponding to the phase difference output and for changing over a filter constant to that for a low frequency corresponding to the frequency change-over signal; and a voltage control oscillator for setting a frequency of the internal clock signal to a frequency corresponding to the output voltage of the loop filter and for decreasing a change amount of an oscillating frequency with respect to an input signal corresponding to the frequency change-over signal.
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申请公布号 |
US5577086(A) |
申请公布日期 |
1996.11.19 |
申请号 |
US19940365479 |
申请日期 |
1994.12.28 |
申请人 |
KABUSHIKI KAISHA TOSHIBA |
发明人 |
FUJIMOTO, YUKIHIRO;NOGAMI, KAZUTAKA |
分类号 |
G01R31/28;H03D13/00;H03K3/282;H03L7/089;H03L7/093;H03L7/099;H03L7/10;H03L7/107;H03L7/113;(IPC1-7):H03D3/24;H03L7/00 |
主分类号 |
G01R31/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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