JPS54131713A - Drive control system for step motor - Google Patents

Abstract

PURPOSE:To reduce power loss of the step motor through high speed disconnection between the phase coil and the power supply when it is held while continuous connection when it is driven by a switch circuit with a unidirectional conduction circuit for current feedback connected to the coil of the motor. CONSTITUTION:Phase signals phiA to phiD from a phase control section are fed to phase coils LA to LD of a step motor passing through AND gates GA to GD and transistors QA to QC. When the motor is driven, a drive control signal is inputted to an OR gate GO to maintain transistors QA to QD in on-state. At this point, the current of the corresponding phase coils LA to LD rises suddenly to be maintained at the drive current level. When the motor is switched to the holding, the drive signal varnishes and instead, according to a hold control signal the transistors QA to QD turned on or off at a high rate. When it is switched off, the feedback of counter electromotive force from diodes DA to DD checks the complete cut of the coil current.