Patent ID: 7262628

Claim:
In a closed loop system, a method of calibrating a digital multiphase voltage regulator having a discrete output at each output phase for providing regulated power to a load, comprising the steps of: providing a low side field effect transistor and a high side field effect transistor connected in series and having a common node at each output phase; coupling an inductor between each output phase and the load; placing the load in a quiescent state such that it draws only leakage current; coupling a calibration current source to the load; obtaining a first voltage measurement by measuring the voltage across the low side field effect transistor with the calibration current source in a first state; storing the first voltage measurement; obtaining a second voltage measurement by measuring the voltage across the low side field effect transistor with the calibration current source in a second state; storing the second voltage measurement; and determining an on resistance of the low side field effect transistor by comparing the first and second voltages.