| CPC H02M 7/5387 (2013.01) [H02M 1/088 (2013.01); H02M 1/32 (2013.01); H02M 1/36 (2013.01)] | 20 Claims |
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1. An apparatus comprising:
a power converter having multiple switches coupled to input voltage rails and to opposing terminals of a coil to be energized, the multiple switches configured to be turned ON or OFF to conduct or block a current, respectively, responsive to switch control signals, wherein the coil includes a degaussing coil to generate a degaussing field responsive to the current; and
a controller to receive a fault command that indicates a failure condition or a power-down condition upon occurrence of the failure condition or the power-down condition, and to generate the switch control signals responsive in part to the fault command to compel the power converter to selectively operate:
when the fault command is not received, in a normal mode in which the multiple switches are periodically turned ON and OFF to supply the current from the input voltage rails to the coil to energize the coil; and
when the fault command is received, in a protection mode in which first switches of the multiple switches are continuously turned ON, and second switches of the multiple switches are continuously turned OFF, to interrupt the current from the input voltage rails, and to circulate an initial current, flowing in the coil when the protection mode is entered responsive to the fault command, through the power converter and the coil to cause the initial current to decay toward zero.
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