发明名称 |
Resistorless phase locked loop circuit employing direct current injection |
摘要 |
A phase locked loop circuit includes a phase/frequency detector which uses a divider circuit and feedback from a clock distribution tree to generate INC and DEC pulses which have no "dead zone". A pair of charge pumps receives the INC and DEC pulses. One charge pump is a differential pump and has voltage controlled common mode feedback circuit to maintain a common mode controlled voltage. A differential current is outputted to a loop filter capacitor by this charge pump. The other charge pump is a single-ended output pump which supplies current to a current controlled oscillator which also receives input from a voltage to current converter. The current controlled oscillator includes a variable resistance load which varies inversely with the magnitude of the input current. A jitter control circuit is provided which reduces jitter in the current controlled oscillator output in the locked phase. Also, a lock indicator is provided which is time independent, and provides a lock indication when the loop enters the locked condition. The circuits for these components are described in detail.
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申请公布号 |
US5513225(A) |
申请公布日期 |
1996.04.30 |
申请号 |
US19940298632 |
申请日期 |
1994.08.31 |
申请人 |
INTERNATIONAL BUSINESS MACHINES CORPORATION |
发明人 |
KELKAR, RAM;NOVOF, ILYA I.;STRAYER, DONALD E.;WYATT, STEPHEN D. |
分类号 |
H03L7/093;H03L7/089;H03L7/095;H03L7/099;H03L7/10;(IPC1-7):H03D3/24 |
主分类号 |
H03L7/093 |
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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