EUM6801
3-Phase Sensorless Fan Motor Driver
DESCRIPTION
EUM6801 is a 3-phase sensorless fan motor driver. It
senses the BEMF (Back Electromotive Force) of the
motor in rotation and provides corresponding
commutation current to the motor. The sensorless
technology doesn’t need Hall sensors. The absence of
the Hall sensor makes the fabrication of the motor
easier, especially suitable for ultra-small motors.
EUM6801 integrates PWM speed control, soft
switching, lock protection, auto restart, fan tachometer
and forward/reverse functions.
As applying 3-phase driver method, PWM mode
controls fan speed by adjusting duty cycle of PWM
signal. Internal soft switching function drives fan
motor in low noise and low vibration ways. EUM6801
can drive motor from stop mode to rotation mode by
adjusting the external capacitor between OSC pin and
GND pin. If a motor is stalled by external force or
obstacles, over-driving current may incur coil overheat
and burning. To prevent motor from overheating, the
lock protection circuit shuts down the internal power
devices for a few seconds after the motor lock is
detected. Then the auto restart circuit resumes to power
up the internal power devices. If the lock still persists,
EUM6801 shuts down power devices for another few
seconds. The lock protection time is built-in and need
no external components. During rotation, FG outputs
signal which represents motor speed. The motor
rotation direction is controlled by setting FR to high or
low.
FEATURES
3-Phase Sensorless Drive Function
(No Hall Sensor Needed)
Few External Components
(3 CAP Only)
Low Startup Voltage: <1.8V
PWM Speed Control and Soft Switching
20μA Low Standby Current
Built in FG Outputs
Built in Thermal Protection
UDFN Small Package with Thermal Pad
(3mm×3mm×0.5mm for Small Fan)
RoHS Compliant and 100% Lead (Pb)-Free
Halogen-Free
APPLICATIONS
NB Fan, Low Noise Fan and Low Power
Consumption Fan
Application Circuit
Figure 1.
DS6801
Ver1.1
Dec. 2010
1
EUTECH [ EUTECH MICROELECTRONICS INC ]
