A 3-phase motor driver circuit has a first input to be coupled to an output of a first phase current sensor, and a second input that represents a zero reference. A controller adjusts one or more of a first phase voltage, a second phase voltage, and a third phase voltage, until a comparison between the first input and the input indicates that the first input has reached the zero reference, and in response the controller captures an output of a second phase current sensor and an output of a third phase current sensor. The controller then stores, in memory, calibration data that is based on the captured outputs of the second and third phase current sensors. Other aspects are also described.