Patent ID: 7443248
Filing Date: 2008-10-28
Classification: H03B,H03D,H03J,H03L

Abstract:
1. A frequency synthesizer for use in a radio frequency (RF) device, comprising: a plurality of current sources operatively coupled to switches, the switches selectively activating or deactivating at least some current sources; and a comparator that compares a DC signal to at least one threshold DC signal, wherein at least some currents of the activated current sources are added together, wherein the switches selectively activate or deactivate the at least some current sources to adjust a characteristic of an output signal of a voltage controlled oscillator (VCO), wherein the comparator and the plurality of current sources are not part of the VCO, wherein the output signal of the VCO is used to generate the DC signal, and wherein the VCO is part of a phase lock loop (PLL) circuit, the gain of the PLL circuit being kept substantially constant, the gain of the PLL circuit being compensated for variations in VCO gain as VCO operating conditions vary.