Abstract: In a PWM-controlled motor driving device, a phase current is prevented from undergoing an abrupt transition at phase current switching points, thereby reducing vibrations and noise of the motor. A PWM control section produces two independent PWM control pulse signals P1 and P2. Two energized phases, which are determined by an energization switching section, are energized with PWM control in parallel according to the PWM control pulse signals P1 and P2. A comparison section compares a current detection signal DS, which indicates the level of the current flowing through a motor coil, with various torque command signals TQ1, TQ2 and TQ3, which are produced by a torque command signal generation section. A masking section masks comparison results CR1 and CR2 as necessary. Thus, an ON period of the PWM control pulse signal P1 and that of the PWM control pulse signal P2 are determined.

Abstract: A motor driver having output circuits each including upper and lower side switching elements connected in series. The motor driver includes: a current detection resistance connected in series with the output circuits in common; a phase switch circuit for turning ON a switching element on one side of one of the output circuits for a time period corresponding to a predetermined electrical angle and switching switching elements on the other side of a plurality of output circuits among the remaining ones of the output circuits; and an ON-period control section for generating a signal for controlling the switching operation so that each of periods obtained by dividing the time period includes a first period in which a plurality of switching elements are turned ON and a second period in which one of the switching elements turned ON in the first period is kept ON.