The invention discloses an H-bridge drive device of an
electric power steering motor of an auto. The device comprises an H-bridge drive module, an H-bridge module, an undervoltage protection module, a motor
armature current feedback module, an MOS tube on-bridge
drain current monitoring and protecting module and an MOS tube down-bridge drain-
electrode current monitoring and protecting module; each arm of the H-bridge module adopts the structure of the parallel connection of three N-channel MOS tubes; the drain electrodes of the three N-channel MOS tubes are connected together, the source electrodes are connected together, and the grid electrodes are connected together after being respectively connected with a
resistor in series; the device reduces the
power loss of the MOS tubes, enhances the drive efficiency of the
H bridge and the reliability of the
system, and can effectively avoid the influences of the emergency switching of the motor, the abrupt increase of the
pulse current of the MOS tubes, and the abrupt change of
armature current of the motor due to the special working conditions such as emergency large turning of an
electric power steering system on the
steering system, thus having high integration degree, good reliability, convenient use and being applicable to the requirement of safety, energy-saving and environment protection of the
auto industry.