Patent ID: 8847587
Filing Date: 2014-09-30
Classification: A61B,H01F

Abstract:
1. A magnetic field generator, comprising: a substrate; a main generator coil, at least one field sensor, and at least one shim coil, all disposed on the substrate; a driver circuit, which is coupled to drive the main generator coil with a driving current at a selected frequency; and a correction circuit, which is coupled to receive a signal at the selected frequency from the at least one field sensor and, in response to deviations in the signal from a predefined baseline, to drive the at least one shim coil with a driving current having an amplitude configured to return the signal to the baseline, the correction circuit being coupled to detect the deviations from the predefined baseline, to estimate the driving current that cancels the deviations, and to drive the at least one shim coil with the estimated driving current.