In general, the invention is directed to techniques for creating and controlling
a magnetic field for use with electronic article surveillance (EAS) markers. In
particular, the techniques make use of current switching devices to generate a
signal having one or more current pulses for creating the magnetic field. An electronic
article surveillance (EAS) system includes a coil to create a magnetic field for
changing a status of an EAS marker and a drive unit to output a signal having one
or more current pulses for energizing the coil. A programmable processor within
the EAS system controls the drive unit to generate the output signal according
to a desired profile. By selectively activating and deactivating current switching
devices within the drive unit, the processor can direct the drive unit to generate
the output signal according to a desired profile having a number of current pulses
of different amplitudes and direction.
