SLEW RATE CIRCUIT FOR HIGH-POTENTIAL-SIDE DRIVER FOR MULTIPHASE DC MOTOR

摘要

PURPOSE: To provide a circuit which controls the slew rate of a high-potential side transistor for a driver with respect to an inductive coil of a motor. CONSTITUTION: An inductive coil 13 of a the motor is connected selectively between a transistor 25 on the supply voltage side at a high potential and a transistor 43 on the reference voltage side at a low potential. Voltage on the high-potential side of the inductor 13 is compared with a voltage on a capacitor 20. When drive to the inductor 13 is turned off, the capacitor 20 is discharged at a fixed rate. A voltage derived from the compared voltage is applied, and a current fed to the high-potential side of the inductor is controlled.