Diodes AH291 - Manual

AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
AH291
Document number: DS31041 Rev. 8 - 2
1 of 9
www.diodes.com
June 2010
© Diodes Incorporated
Description
AH291 is a monolithic fan motor controller with Hall sensor’s
capability. It contains two complementary open-collector
drivers for motor’s coil driving, automatic lock shutdown and
restart function relatively.
Rotor-lock shutdown detection circuit turns off the output
driver when the rotor is blocked to avoid coil overheat. Then,
the automatic recovery circuit will restart the motor. These
protected actions are repeated and periodic during the
blocked period. Until the blocking is removed, the motor
recovers and runs normally.
The AH291 is available in SIP4 and SOT89-5L packages.
Features
• On Chip Hall Sensor
• Rotor-Locked
Shutdown
• Automatically Restart
• Built-in Zener Protection for Output Driver
• Operating Voltage: 1.8V to 5.75V
• Output Current: I
O(AVE)
= 400mA
• Packages: SIP-4L and SOT89-5L
• Green Molding Compound
Pin Assignments
291
1 2 4 3
1 : Vdd
2 : DO
3 : DOB
4 : GND
SIP-4L
(Top View)
1
2
3 74
5
DOB DO
GND
NC Vdd
SOT89-5L
291
(Top View)
Applications
• Two-coil BLDC cooling fans
• Low to medium voltage, low power BLDC motors
Typical Application Circuit (Note 1)
V
dd
DOB
DO
GND
1.8V/5.75V D2
L2 L1
291
1 2 3 4
D1
R1 R2
C1 C2
Notes: 1. R1, R2: typical 56 Ohm
C1, C2, C3: typical 2.2µF
The R, C value need to be fine tuned based on coils design.
C3
1.8V/5.75V Brush-Less DC Fan