BD67173NUX Datasheet, PDF (12/30 Pages) Rohm – Three-Phase Full-Wave Fan Motor Driver

BD67173NUX
2. Sensorless Drive
BD67173NUX is a motor driver IC for driving a three-phase brushless DC motor without a hall sensor. Detecting
a rotor location firstly at startup, an appropriate logic for the rotation direction is obtained using this information
and given to each phase to rotate the motor. Then, the rotation of the motor induces electromotive
voltage in each phase wiring and the logic based on the induced electromotive voltage is applied to the each
phase to continue rotating.
2.1 Motor Drive Output Voltage and Current U, V, and W
The timing charts of the output signals from the U, V and W output is shown (Figure 6.).
The detection of the BEMF voltage does with output U, V, and W (for rise and fall zero-cross) and detects the position of
the motor rotation.
Position[deg] 0
60
120
180
240
300
360
60
120
180
240
300
360
Output Voltage
U
Output Voltage
V
Output Voltage
W
Output Current
U
Output Current
V
Output Current
W
Soft switching of PMW operation
Figure 22. Motor Drive Output Timing Chart
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TSZ02201-0H1H0B101160-1-2
08.Sep.2015 Rev.001