| 摘要 |
The circuit detects a phase of counter electro motive force for 3 phase motor in stead of a hall device, reduces a design burden to wire-noise and cost-down, and stably drives 3 phase motor by adjustment of motor coil currents. The circuit includes a predrive unit (60), a motor drive unit (70), a 3 phase motor (80),a magnetic resisance device (40), a counter electromotive force sensor (140) which senses a counter electro motive force from coils (81-83) of 3 phase motor (80), a zero sensor (150), a latch(160), a comparator (170), a pulse generator (180) which controls a motor speed, and a magnetic resistor (40) which detects a output pulse width of pulse generator (180).
|
