Patent ID: 7663446

Claim:
A voltage controlled oscillator (VCO), comprising: 2n+1 transconductors configured to provide an oscillating signal, wherein n≧1; one or more external device pins configured to provide a voltage supply control signal; a voltage selecting circuit configured to receive a plurality of reference voltages and said voltage supply control signal, said voltage selecting circuit further configured to select one of said plurality of reference voltages in response to said voltage supply control signal; a voltage regulator coupled to each of said transconductors and said voltage selecting circuit said voltage regulator configured to receive said selected reference voltage from said voltage selecting circuit and provide a supply voltage to each of said transconductors, wherein said supply voltage depends on a value of said selected reference voltage, and a frequency range of said oscillating signal depends on a value of said supply voltage; and an adjustable bias voltage coupled to each of said transconductors, wherein a frequency of said VCO depends on a value of said adjustable bias voltage.