Patent ID: 7616074

Claim:
A circuit for controlling a startup time of an oscillator circuit, comprising: a variable current source coupled to the oscillator circuit, wherein a startup time of the oscillator circuit is proportional to a bias current input into the oscillator circuit from the variable current source; and a control mechanism coupled to the variable current source and to the output of the oscillator circuit, wherein upon startup the control mechanism is configured to adjust the variable current source to input a large startup bias current into the oscillator circuit; and an oscillation-detection mechanism in the control mechanism, wherein the oscillation-detection mechanism includes: a counter mechanism configured to count transitions in the output of the oscillator circuit; and an adjustment mechanism configured to adjust the variable current source to input a reduced steady-state bias current into the oscillator circuit after the transition count for the output of the oscillator circuit reaches a predetermined number during startup; wherein the control mechanism adjusts the variable current source to one or more bias currents between the large startup bias current and the steady-state bias current when a predetermined number of oscillations corresponding to each of the one or more bias currents have occurred during startup.