Patent ID: 8384336

Claim:
A multiphase motor driving device comprising: an inverter circuit comprising: a pair of upper and lower switching elements arranged in correspondence to each of a plurality of phases, a shunt resistor for phase current detection connected to each switching element on a lower side of each phase, and a voltage for driving a multiphase motor retrieved from a node of the pair of switching elements in each phase; and a control unit for controlling ON/OFF operation of each switching element of the inverter circuit, wherein the multiphase motor driving device detects a current flowing to the shunt resistor during an OFF period of the switching element on the upper side; a determination unit for shifting a detection timing of the current flowing to the shunt resistor of a certain phase from the OFF period to the ON period of the switching element on the upper side in the phase and determining whether or not ON failure in which the switching element on the lower side in the phase remains in the ON state occurred based on the current flowing to the shunt resistor of the phase in the ON period; and a current value estimation unit for estimating a current value of the phase in a case where the detection timing is shifted based on currents flowing to the shunt resistors of other phases.