DRIVE DEVICE OF BRUSHLESS MOTOR

摘要

PURPOSE:To prevent the rotation irregularity in a motor due to the mutual interference of signals by initializing the triangular wave of a PWM control part based on a reference clock used for PLL control. CONSTITUTION:An upper/lower three-differential distribution part 16 distributes the position detection signal from a Hall electron 20 for each phase and distributes it to an output part 12. A PLL control part 22 compares the phase of a reference clock CLK and that of FG signal, supplies a torque command signal VT to the upper/lower three-dimensional distribution part 16, thus being synthesized to signals II and II' corresponding to output transistors(Tr) Q1-Q6. A PWM control part 50 detects the voltage range of the motor drive voltage of output terminals OUT1-OUT3 and controls a power supply side voltage VM of Tr Q1-Q6. Namely, the upper-side or lower-side voltage of the envelope of a motor drive voltage is compared with a reference voltage. Then, the signal is compared with a triangular wave and a PWM signal corresponding to the level of the signal is integrated to obtain a power-supply side voltage VM. Also, the triangular wave is initialized based on the signal of a reference clock generation part 40.