Patent ID: 8786242

Claim:
A method comprising: exciting a load in a system comprising the load and a supply voltage having a first polarity with a known first duty cycle for a first time interval following a start time, where the load comprises an inductive element; at an end of the first time interval, sensing, at a first end time, a first end load current, where a first load current flows through the load; and calculating a lumped term based at least in part on the first time interval and a change in the first load current during the first time interval, where the lumped term is representative of the supply voltage and at least one electrical characteristic of the load; exciting the load with a second known duty cycle having an opposite polarity to the first polarity for a second time interval following the first end time; at the end of the second time interval, sensing, at a second end time, a second end load current in the system; and re-calculating the lumped term based at least in part on the first end load current, the second end load current and the second time interval.