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December 2013 DocID14109 Rev 3 1/26
AN2650
Application note
L9942 stepper motor driver for bipolar stepper motors
Introduction
The L9942 is an integrated stepper motor driver for bipolar stepper motors. The device is
designed for automotive applications, such as headlamp leveling, steerable lights and
adaptive front lighting. Other applications, such as ventilation and air conditioning flap and
throttle positioning are also possible uses for the L9942.
The device drives bipolar stepper motors with high-efficiency and smooth operation. Micro-
stepping is the preferred mode to provide low-noise operation since this technique
eliminates the effects of mechanical resonances, which can lower the motor torque.
A motor stall detection capability allows position alignment without an external sensor, while
its step counter is addressable via an SPI as well as by a separate input, to prevent the SPI
overloading when running multiple motors simultaneously.
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