AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
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.
Pin Assignments
(Top View)
291
1 : Vdd
2 : DO
3 : DOB
4 : GND
1 2
3
4
(Top View)
Vdd
1
2
291
5
NC
GND
DO
3
7
DOB
4
SOT89-5L
SIP-4L
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
Applications
•
•
Two-coil BLDC cooling fans
Low to medium voltage, low power BLDC motors
Typical Application Circuit
(Note 1)
1.8V/5.75V
V
dd
D2
D1
291
L2
L1
1
2
3
4
GND
C3
DO
Notes:
DOB
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.
R1
C1
R2
C2
1.8V/5.75V Brush-Less DC Fan
AH291
Document number: DS31041 Rev. 8 - 2
1 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
Pin Descriptions
Pin Name
Vdd
DO
DOB
GND
NC
Description
Input Power
Output Pin
Output Pin
Ground
Not Connected
Functional Block Diagram
Vdd
Lock detect,
shutdown and
automatic re-start
Regulator
DO
Hall
Plate
Amp.
Control Logic
DOB
GND
AH291
Document number: DS31041 Rev. 8 - 2
2 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
Absolute Maximum Ratings
(T
A
= 25°C)
Symbol
Vdd
I
O
P
D
T
ST
T
J
Characteristics
Operating Supply Voltage
Output Current
I
O(AVE)
I
O(PEAK)
SIP-4L
SOT89-5L
SIP-4L
SOT89-5L
Rating
8
400
400
700
550
800
-55 ~ 150
150
Unit
V
mA
mA
mA
mW
mW
°C
°C
Power Dissipation
Storage Temperature
Maximum Junction Temperature
Recommended Operating Conditions
Symbol
Vdd
T
A
Notes:
Characteristic
Supply Voltage (Note 2)
Operating Ambient Temperature
Conditions
Operating
Operating
Min
1.8
-20
Max
5.75
100
Unit
V
°C
2. The output of IC will be switched after the supply voltage is over 1.8V, but the magnetic characteristics won't be normal until the
supply is over 2.0V.
Electrical Characteristics
(T
A
= 25
°C,
Vdd = 5V, unless otherwise specified)
Symbol
Idd
T
RLP-ON
T
RLP-OFF
Characteristics
Supply Current
Rotor Lock Protection On Time
Rotor Lock Protection Off Time
Output Saturation Voltage
Output On Resistance
Output Zener-Breakdown Voltage
Conditions
Operating
Min
-
-
2.4
-
-
-
-
Typ.
2.6
0.4
3
300
600
1.75
15
Max
4.0
-
3.6
-
-
-
-
Unit
mA
Sec
Sec
mV
mV
ohm
V
V
OUT ( SAT )
R
DS(ON)
Vz
Truth Table
IN-
H
L
-
I
O
= 180mA
I
O
= 350mA
IN+
L
H
-
CT
L
L
H
OUT1
H
L
off
OUT2
L
H
off
Mode
Rotating
Rotating
Lockup protection activated
AH291
Document number: DS31041 Rev. 8 - 2
3 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
Magnetic Characteristics
(T
A
= 25
°C,
Vcc = 24V, unless otherwise specified,
Note 3)
(1mT = 10 Gauss)
Max
Unit
60
-
-
Gauss
Gauss
Gauss
Symbol
Bop
Brp
Bhy
Notes:
Characteristics
Operation Point
Release Point
Hysteresis
Min
-
-60
-
Typ.
30
-30
60
3. The magnetic characteristics may vary with supply voltage, operating temperature and after soldering.
Operating Characteristics
DOB
DO
Output Voltage in Volts
Output Voltage in Volts
RP
12
10
8
6
4
OFF
OFF
12
10
8
6
4
OP
ON
2
OP
V
SAT
RP
2
ON
V
SAT
Brp
0
Bop
Brp
0
Bop
Magnetic Flux Density in Gauss
Magnetic Flux Density in Gauss
S
Marking
side
S
Marking
side
N
( SIP-4L )
N
( SOT89-5L )
AH291
Document number: DS31041 Rev. 8 - 2
4 of 9
www.diodes.com
June 2010
© Diodes Incorporated
AH291
LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR
CONTROLLER
Performance Characteristics
(1) SIP-4L
T
A
(°C)
P
D
(mW)
T
A
(°C)
P
D
(mW)
P
D
(mW )
6 00
5 00
4 00
3 00
2 00
1 00
0
0
25
50
75
10 0
125
15 0
T
A
(°C )
25
550
105
198
50
440
110
176
60
396
115
154
70
352
120
132
80
308
125
110
85
286
130
88
90
264
135
66
95
242
140
44
100
220
150
0
Pow er D iss ipation Curv e
(2) SOT89-5L
T
A
(°C)
P
D
(mW)
T
A
(°C)
P
D
(mW)
25
800
105
288
50
640
110
256
60
576
115
224
70
512
120
192
75
480
125
160
80
448
130
128
85
416
135
96
90
384
140
64
95
352
145
32
100
320
150
0
P
D
(mW )
900
800
700
600
500
400
300
200
100
0
-4 0
0
25
Power Dissipation Curve
50
75
10 0
125
1 50
T
A
(°C)
AH291
Document number: DS31041 Rev. 8 - 2
5 of 9
www.diodes.com
June 2010
© Diodes Incorporated
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