专利名称：Apparatus and method for phase lock loop
gain control using unit current sources
发明人：Ramon A. Gomez申请号：US11314618申请日：20051221
公开号：US20060097797A1公开日：20060511
专利附图：
摘要：A gain compensator compensates for the gain variation of a varactor-tunedvoltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LCcircuit 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 chargepump reference current that is based on the same capacitor control signal that controlsthe fixed capacitors in the LC circuit. The gain compensator generates the charge pumpreference current by replicating a reference scale current using unit current sources. Thenumber 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 thePLL. The reference scale current is generated based on a PLL control that specificscertain PLL characteristics such as reference frequency, loop bandwidth, and loopdamping. Therefore, the reference pump current can be efficiently optimized forchanging PLL operating conditions, in addition to compensating for variable VCO gain.
申请人：Ramon A. Gomez
地址：San Juan Capistrano CA US
国籍：US
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