The L9942 is an integrated bipolar stepper motor driver primarily used in automotive headlamp leveling. It can also be used for other stepper motor operations. This application note explains the advantages of using Back Electro-Motive Force (BEMF) as a method for determining rotor or armature stall conditions.
The document focuses on the L9942, an integrated stepper motor driver primarily used for automotive head lamp leveling but applicable to other operations like HVAC and EGR valve control. It details how Back EMF (BEMF) sensing can be utilized to detect stall conditions during microstepping operations.
The text covers universal motor concepts, including the relationship between BEMF and armature speed, as well as the proportionality between torque and current. It explains how loading affects the phase shift of the BEMF relative to drive current and describes the specific algorithm for detecting when a motor has stalled.
| Motor Type | bipolar stepper motors |
|---|---|
| Primary Application | automotive head lamp leveling |
| Microstepping Steps | 32 programmable current regulated steps |
The L9942 is an integrated stepper motor driver used primarily in automotive head lamp leveling.
Yes, it can be used for adaptive head lamp leveling, HVAC blend door actuator control, EGR valve and throttle control.
The document explains the advantages of sensing Back Electro-Motive Force (back EMF or BEMF) as a method for determining rotor or armature stall conditions.