Patent ID: 8605466

Claim:
A radiation hardened motor drive stage, comprising: (a) a non radiation hardened P-channel FET switch connected to each of three pairs of upper and lower switch blocks or legs of said motor drive stage, where each output of a representative one of said three pairs of switch blocks or legs is connected to a respective winding terminal of a motor, said upper switch blocks or legs being connected to an output of said FET switch and said lower blocks or legs being connected to a negative power bus; and (b) a DC-DC converter bias supply that operates from an input power bus and enables said non-radiation hardened P-channel FET switch, wherein (1) the three pairs of upper and lower switch blocks or legs, each have either a non-radiation hardened N-channel FET or a non-radiation hardened IGBT, (2) said DC-DC converter produces two pairs of isolated outputs to control one or more of the three pairs of switch blocks or legs that has been exposed to ionizing radiation, and (3) a negative bias voltage of the DC-DC converter further serves to control the ionizing radiation even when gate thresholds for the upper and lower switch blocks or legs drop below zero.