Patent ID: 8130053

Claim:
A method of tuning a LC tank circuit, and outputting a radio frequency (RF) signal responding to an input RF signal, the LC tank circuit comprising an inductor and a variable capacitor having independently variable coarse and fine capacitances wherein the coarse capacitance is greater than the fine capacitance, the method comprising: in a coarse phase of a tuning mode, incrementing/decrementing a control input to the coarse variable capacitor to vary its capacitance between a minimum and maximum value; monitoring the magnitude of the output RF signal as the control input changes; detecting a peak in the output RF signal; and storing the coarse variable capacitor control input value associated with the output RF signal peak; in a fine phase of a tuning mode, applying the stored coarse variable capacitor control input value to the variable capacitor; incrementing/decrementing a control input to the fine variable capacitor to vary its capacitance between a minimum and maximum value; monitoring the magnitude of the output RF signal as the control input changes; detecting a peak in the output RF signal; and storing the fine variable capacitor control input value associated with the output RF signal peak; and in an operating mode, applying the stored coarse and fine variable capacitor control input values to the respective coarse and fine capacitances of the variable capacitor.