Advanced Micro Devices, Inc.
Oscillator calibration

Abstract:

An oscillator circuit includes a first oscillator, a second oscillator, and a calibration circuit to calibrate the first and second oscillators. The first oscillator is supplied with a first supply voltage, and the second oscillator is supplied with a second supply voltage. The calibration includes setting a frequency control of the second oscillator at a target frequency. Then, a voltage control of the second supply voltage is adjusted incrementally until a first control value is identified at which a second oscillator output frequency matches the target frequency. Then, a voltage control of the first supply voltage is set to the first control value. Then, the voltage control for the first supply voltage is adjusted incrementally until a second control value is identified at which a first oscillator output frequency is as close to the second oscillator output frequency as is achievable, but does not exceed it.