Three-phase brushless motor drive circuit

摘要

PURPOSE: To prevent inversion of signal due to switching noise of main circuit by amplifying an output signal from a Hall element and removing noise therefrom, while furthermore synchronizing switching of main circuit elements and making a decision of High or Low. ;CONSTITUTION: Output signal from a Hall element 20 for detecting the rotor pole position of a motor is amplified through a differential amplifier 10 provided with a filter and delivered to a decision unit 9. An edge synthesizing unit 23 produces logical sum of the edges or a clock signal and a PWM signal fed from a triangular wave and clock generator 13 thus actuating the decision unit 9. Outputs from respective decision units are distributed through a distributing circuit 8 to arm driving circuits 4, 5 thus driving an output switching element 6. Since decision operation is started prior to production of switching noise, faint output signal from a Hall element is protected against influence of noise due to switching of main circuit resulting in elimination of external circuit for converting Hall element signal into a logical signal.;COPYRIGHT: (C)1993,JPO&Japio