The L99SM81V is an automotive grade integrated driver for bipolar two-phase stepper motors capable of current controlled micro-stepping with programmable amplitude. The device features a 5 V voltage regulator to supply external sensors.
The integrated Serial Peripheral Interface (SPI) makes it possible to adjust device parameters, control all operating modes and read out diagnostic information. Digital I/Os are also optionally usable for more flexible and reliable application control.
· AEC-Q100 qualified
· Stepper motor driver with up to 1.35 A current capability
· Programmable Step mode:
- Full step, Half step, Mini step, 1/8 Micro step, 1/16 Micro step
· Current regulation by integrated PWM control with fully integrated current sensing
· Equivalent 10 bit resolution on current regulation loop:
- Two 4-bit programmable full scale current amplitudes: one for RUN and one for HOLD mode
- 6-bit DAC for reference current generation (whatever programmed full scale amplitude)
· 4 programmable decay modes:
- Slow-mode, mixed-mode and 2x automatically selected decay-modes
· 3x programmable inputs for direct control of step clock, direction, hold and step modes
· 1x programmable analog output for Tj measurement or band-gap reference
· 2x programmable digital outputs for internally generated PWM ON duty cycles,error signals, coils voltage measurement synchronization signals
· Programmable MOSFETs switching speed: four options for EMC and power dissipation trade-off optimization
· PWM frequency wobbling for reduction of conducted EM energy
· Outputs protection and diagnosis (open load, short to battery, short to GND)
· Integrated ADC for coil voltage measurement and stall detection
· 5 V low drop voltage regulator short-circuit protected
· Very low current consumption in standby mode (typ. 10 μA)
· Thermal warning and shutdown
· ST SPI 4.1 interface for control and diagnostics
Bipolar 2 phase stepper motor driver for automotive applications like adaptive front light systems or projectors for head-up displaying
The AEK-MOT-SM81M1 evaluation board is designed to drive a bipolar stepper
motor in micro-stepping mode, with coil voltage monitoring for stall detection.
This application board features the automotive-grade L99SM81V stepper motordriver with embedded power MOSFETs and a comprehensive set of I/Os for MCUcontrol and feedback signaling using SPI communication through a 12-pin maleconnector or two 5-pin connectors on the board.
The board is developed as part of the AutoDevKit initiative, and evaluation firmwareis available for suitable microcontrollers such as the automotive-grade SPC5 seriesMCU on the AEK-MCU-C4MLIT1 control board.
The AEK-MOT-SM81M1 board targets automotive applications such as adaptive front lighting systems and HUDprojectors, with stepping resolution ranging from 4 full steps to 64 micro steps for the finest possible positionalcontrol.
The L99SM81V driver logically manages timers, counters, reference tables and mode or status registers that areread or set by the external microcontroller to drive the two coil phases of a bipolar stepper motor, with separateRUN and HOLD profiles for moving the rotor or keeping it stationary.
Apart from supply voltage and driver current diagnostics, the driver also monitors the output voltages across thephase terminals in order to detect and flag critical motor stall events that can compromise motor operation andcontrol.
• Board functionality based on L99SM81V programmable stepper motor driver forautomotive applications:
–with micro-stepping and hold functions
– BEMF monitoring for stall detection
–programmable configuration via SPI
– 5 V internal linear voltage regulator (output available on board connector)
• Board reverse battery protection with STD95N4F3 MOSFET, which can besubstituted with two optionally mounted diodes and a jumper
• Input operating voltage range from 6 V to 28 V
• Output current up to 1.35 A
• Board size: 65 mm length x 81 mm width x 11 mm maximum component height
• WEEE and RoHS compliant
• All ST components are qualified Automotive grade
• Part of the AutoDevKit™ initiative
• Applications: automotive bipolar stepper motor