Patent Number: 6,528,965

Title: Drive circuit of brushless motor

Abstract: A drive circuit of a brushless motor including a search coil L1 and a drivecoil L2 is comprised of a Schmitt trigger circuit formed by a firstoperational amplifier OP1 which detects rotation of the motor by thesearch coil L1, and an oscillator circuit formed by a second operationalamplifier OP2 which functions as an inverter during rotation of the motorand functions as a rotation stoppage signal-delivering section duringstoppage of the motor, whereby the drive coil L2 is caused to bealternately driven by the first operational amplifier OP1 and the secondoperational amplifier OP2. This makes it possible to realize the drivecircuit of the brushless motor by a simple construction using twooperational amplifiers, and detect the stoppage of rotation of the motor,by causing the second operational amplifier to deliver a oscillatingsignal to the outside, when the rotation of the rotor is stopped.

Inventors: Nakatukasa; Hirotaka (Tokyo, JP)

Assignee:

International Classification: H02P 6/00 (20060101); H02P 6/24 (20060101); H02P 001/24 ()

Expiration Date: 03/02015