公开(公告)号：US20020135428A1

公开(公告)日：2002-09-26

申请号：US09811611

申请日：2001-03-20

Applicant: Broadcom Corporation

Inventor： Ramon A. Gomez

IPC: H03L007/093 ,  H03L007/099

CPC classification number: H03L7/00 ,  H03B5/1212 ,  H03B5/1215 ,  H03B5/1228 ,  H03B5/1243 ,  H03B5/1253 ,  H03B5/1265 ,  H03B5/1278 ,  H03B2200/0046 ,  H03B2200/0048 ,  H03B2200/005 ,  H03B2201/02 ,  H03B2201/0208 ,  H03B2201/025 ,  H03D7/165 ,  H03D7/18 ,  H03J5/244 ,  H03J2200/10 ,  H03L7/0898 ,  H03L7/093 ,  H03L7/099 ,  H03L7/10 ,  H03L7/107 ,  H03L7/1072 ,  H03L7/18

Abstract: A gain compensator compensates for the gain variation of a varactor-tuned voltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LC circuit having multiple fixed capacitors that can be switched-in or switched-out of the LC circuit according to a capacitor control signal to perform band-select tuning of the VCO. The gain compensator compensates for the variable VCO gain by generating a charge pump reference current that is based on the same capacitor control signal that controls the fixed capacitors in the LC circuit. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The number of times the reference scale current is replicated is based on the fixed capacitance that is switched-in to the LC circuit and therefore the frequency band of the PLL. The reference scale current is generated based on a PLL control that specifics certain PLL characteristics such as reference frequency, loop bandwidth, and loop damping. Therefore, the reference pump current can be efficiently optimized for changing PLL operating conditions, in addition to compensating for variable VCO gain.

Abstract translation: 增益补偿器补偿锁相环（PLL）中变容二极管调谐电压调谐振荡器（VCO）的增益变化。 VCO包括具有多个固定电容器的并联LC电路，其可以根据电容器控制信号切换或切换出LC电路，以执行VCO的频带选择调谐。 增益补偿器通过产生基于控制LC电路中的固定电容器的相同电容器控制信号的电荷泵参考电流来补偿可变VCO增益。 增益补偿器通过使用单位电流源复制参考刻度电流来产生电荷泵参考电流。 参考比例电流复制的次数是基于切换到LC电路的固定电容，因此是PLL的频带。 参考比例电流是基于特定于参考频率，环路带宽和环路阻尼等特定PLL特性的PLL控制产生的。 因此，除了补偿可变VCO增益之外，参考泵电流可以有效地优化用于改变PLL工作条件。