发明名称 |
CMOS voltage controlled oscillator. |
摘要 |
<p>The present invention provides a high frequency CMOS voltage controlled oscillator circuit with gain constant and duty cycle compensation. The voltage controlled oscillator circuit includes a multi-stage ring oscillator that includes a plurality of series-connected inverter stages comprising N-channel and P-channel transistors. The ring oscillator responds to a control current signal for controlling the frequency of oscillation of the ring oscillator. A voltage-to-current converter converts a tuning voltage input signal to a corresponding output current signal that is independent of the channel strength of the N-channel and P-channel transistors. Process compensation circuitry responds to the tuning voltage input signal to provide a current dump output signal corresponding to the channel strength of the P-channel and N-channel transistors. Trip-point compensation circuit provides a net ring current signal as the current control signal to the ring oscillator. The net ring current signal represents the difference between the output current signal and the current dump output signal and responds to the balance between the output buffer trip point and a ring oscillator dummy stage. <IMAGE></p> |
申请公布号 |
EP0495573(A2) |
申请公布日期 |
1992.07.22 |
申请号 |
EP19920300100 |
申请日期 |
1992.01.07 |
申请人 |
NATIONAL SEMICONDUCTOR CORPORATION |
发明人 |
RASMUSSEN, RICHARD R. |
分类号 |
H03K3/03;G05F3/24;H03K3/011;H03K3/354;H03L7/099 |
主分类号 |
H03K3/03 |
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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