Drive circuit of the DC brushless motor, how to use the drive circuit of the DC brushless motor and dynamic air bearing type polygon scanner

摘要

PURPOSE: To shorten the stop time by a constitution wherein a drive coil is conducted based on the combination of a speed control signal, produced by comparing a target speed signal with a rotational speed signal, and a conduction switching signal, i.e., a position detection signal, and a brake circuit conducts a sweep current to the drive coil based on a reference signal. ;CONSTITUTION: The drive coil 51 of a motor 5 is conducted with the pulse width of a speed control pulse 82a based on the combination of a speed control pulse 82a from a PWM circuit 82 and a conduction switching signal 83b from a conduction switching circuit 83. A position detection signal 83a is generated when each rotational position of the motor 5 is detected. Upon receiving a reference signal 83c, a brake circuit in the conduction switching circuit 83 turns the gates 2, 5, 8 of switching elements (Tr) S4-S6 for conducting the drive coil in a switching circuit 84 ON. Furthermore, the Tr S4-S6 are short-circuited along with diodes D4-D6. Consequently, the generated current is regenerated and the stop time of the motor 5 is shortened.;COPYRIGHT: (C)1995,JPO