Precision current sensing using low cost sense resistance

Abstract

Apparatus and associated methods relate to configuring a circuit to sense current in a low-cost non-precision resistance, calibrating the circuit to correct inaccuracy measured in the sensed current, and measuring with the corrected circuit the precise current sensed in the low-cost non-precision resistance. In an illustrative example, the low-cost non-precision resistance may be a metal trace on a printed circuit board. The circuit may be calibrated, for example, over a range of currents or temperatures, permitting automatic adjustment to a wide range of non-precision resistance parameter values and environmental conditions. In some examples, correcting coefficients may be adapted to compensate for resistance non-linearities, which may include skin effect or self-heating. Some embodiments may verify the calibrated correction over a range of current and temperature. Various examples may advantageously provide high precision measurement at reduced cost, based on calibrating a circuit to obtain corrected measurement sensed with a low-cost non-precision resistance.