CMD1668M,CMD1667M
Two-Phase Unipolar Drive Brushless Motor Drivers
Automatic Recovery Circuit C-Pin Voltage
1. While the blades are turning, the capacitor is charged with a current of about 3 µA (typical), and C is discharged by
pulses that correspond to the motor speed.
2. When the blades lock, the capacitor is no longer discharged, and the voltage across the capacitor increases. The
output is turned off when that voltage reaches 0.8
×
V
IN
.
3. When the output is turned off, the capacitor is discharged at about 0.44 µA (typical). When the capacitor voltage falls
under V
TH
2, if the lock state is not yet cleared the capacitor continues discharging until V
TH
1. (Note that the output is
turned on at this time.) These operations, i.e. items 2. and 3., are repeated with a ton:toff ratio of about 1:6 to protect
the motor.
4. If the lock is cleared at the point the capacitor voltage reaches V
TH
2, motor rotation is started by turning the output
on.
* All specs and applications shown above subject to change without prior notice.
1F-5 NO.66 SEC.2 NAN-KAN RD ., LUCHU , TAOYUAN, TAIWAN
Email: server@ceramate.com.tw
Tel:886-3-3214525
Http: www.ceramate.com.tw
Page 8 of 9
Rev 1.0 Aug. 23,2004
.
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