Overview

The LB1847 is a driver IC for stepping motors with PWM current control bipolar drive (fixed OFF time). A special feature of this IC is that VREF voltageis constant while the current can be set in 15 steps, allowing drive of motors ranging from 1-2 phase exciter types to 4W 1-2 phase exciter types. The current decay pattern can alsobe selected (SLOW DECAY, FAST DECAY, MIX DECAY) to increase the decay of regenerative current at chopping OFF,thereby improving response

characteristics. This is especially usefulfor carriage and paper feed stepping motors in printers and similar applications where high-precision control and low vibrations are required.

Features

•PWM current control (fixed OFF time)

•Load current digital selector (1-2, W1-2, 2W1-2, 4W1-2 phase exciter drive possible)

•Selectable current decay pattern (SLOW DECAY, FAST DECAY, MIX DECAY)

•Simultaneous ON prevention function (feed-through current prevention)

•Noise canceler

•Built-in thermal shutdown circuit

•Built-in logic low-voltage OFF circuit