MLX90283 Datasheet, PDF (5/10 Pages) Melexis Microelectronic Systems – BLDC Vibration Motor Driver

MLX90283
BLDC Vibration Motor Driver
9 Detailed General Description
The MLX90283 is a complete one-chip solution for driving BLDC vibration motors.
As a result of the low output resistance of the full bridge output and the low supply current, the IC provides
high driving performance and increased motor efficiency.
The built-in reverse voltage protection avoids any damage in case the supply voltage is accidentally reversed.
The UTQFN package requires only 3mm² PCB surface. The 0.4mm thickness enables production of very
small and thin vibration motors.
The package also includes an Exposed Pad for enhanced thermal performance.
10 Unique Features
The new proprietary design from Melexis “Active Start” provides an appropriate solution against the major
source of vibration motor start-up reliability issue: rotor stalled close to the dead point. When the rotor
position is close to the dead point the force produced by the stator is not sufficient to overcome the
mechanical friction. The rotor is stalled and cannot start rotating without an additional external force.
The “Active Start” function is activated if the magnetic pole sensed by the device does not change for more
than 110ms typical. In this mode the device effectively decreases the mechanical friction by applying a
special shaking signal to the motor coil which helps to overcome the dead point position. The function is
immediately deactivated after a change in the magnetic pole sensed by the device.
A BLDC vibration motor is designed and optimised for one rotation direction (clockwise or counter-clockwise).
Rotating in the reverse direction inevitably leads to a reduction of the motor performance as loss in revolution
per minute and higher current consumption.
The Active Start favours the normal rotation direction to always ensure the highest motor performance.
Vibration motors are predominantly used in battery-powered applications. Low power consumption is a critical
characteristic to ensure longer operation time.
Based on the “Freewheel” principle, the MLX90283 features a special motor driving technique to lower the
motor current consumption. With optimized position of the Hall sensor in the vibration motor, the Freewheel
event occurs only when the motor torque is low. Cutting this part of the motor torque does not affect the
rotation speed while the motor current consumption is reduced proportionally to the rotation speed. This
simple and efficient system directly improves the motor efficiency.
The Freewheel principle enables to reach high rotation speed with lower power consumption than usual.
3901090283
Rev 001
Page 5 of 10
Datasheet
October/07