Diodes AH292 User Manual

AH292

LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR

CONTROLLER

Description

AH292 is a monolithic fan motor controller with Hall sensor’s capability. It contains two complementary open-collector transistors for motor’s coil driving, automatic lock current shutdown, and recovery protections. In addition a Frequency generator (FG) output is also available for speed detection.

Rotor-lock shutdown detection circuit turns off the output driver when the rotor is blocked to avoid coil overheat. T hen, 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 AH292 is available in SOT89-5L package.

Features

• On Chip Hall Sensor

• Rotor-Locked Shutdown

• Automatically Restart

• Frequency Generator (FG) Output

• Built-in Zener Protection for Output Driver

• Operating Voltage: 1.8V to 5.75V

• Output Current: I

• Packaged in SOT89-5L

• Green Molding Compound

O(AVE)

= 400mA

Pin Assignments

(Top View)

Vdd

1

GND

2

3 7

292

SOT89-5L

FG

5

DOBDO

4

Applications

• Two-coil BLDC cooling fans

• Low to medium voltage, low power BLDC motors

Typical Application Circuit (Note 1)

Vdd

(1.8V/5.75V)

D1

FG

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.

1.8V/5.75V DC Brush-less Fan with FG output function

AH292

Document number: DS31049 Rev. 7 - 2

R

pu

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1

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D2

292

32

C3

Coil 2 Coil 1

4

5

GND

R1 R2

C1 C2

June 2010

Pin Descriptions

Pin Name Description

FG Frequency Generation

Vdd Input Power

DO Output Pin DOB Output Pin GND Ground

Functional Block Diagram

Vdd

AH292

LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR

CONTROLLER

Regulator

Hall

Plate

AH292

Document number: DS31049 Rev. 7 - 2

Amp.

Lock detect,

shutdown and

automatic re-start

Control Logic

GND

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FG

DO

DOB

June 2010

AH292

LOW VOLTAGE HALL-EFFECT SMART FAN MOTOR

CONTROLLER

Absolute Maximum Ratings (T

Symbol Characteristics Rating Unit

Vdd Operating Supply Voltage 8 V

I

Output Current 400 mA

O(AVE)

I

Output Current 700 mA

O(PEAK)

PD Power Dissipation 800 mW

TST Storage Temperature -55 ~ 150

TJ Maximum Junction Temperature 150

Recommended Operating Conditions

Symbol Characteristic Conditions Min Max Unit

Vdd Supply Voltage (Note 2) Operating 1.8 5.75 V

TA Operating Ambient Temp erature Operating -20 100

Notes: 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.

= 25°C)

A

°C °C

°C

Electrical Characteristics (T

= 25 °C, Vdd = 5V, unless otherwise specified)

A

Symbol Characteristics Conditions Min Typ. Max Unit

Idd Supply current Operating - 2.6 4.0 mA

T

RLP-ON

T

RLP-OFF

V

OUT(SAT)

R

DS(ON)

Rotor Lock Protection On Time - 0.4 - Sec Rotor Lock Protection Off Time 2.4 3 3.6 Sec

I

= 180mA - 300 - mV

Output Saturation Voltage

O

IO = 350mA - 600 - mV

Output On Resistance - 1.75 - ohm

VOL FG Output Vds IO = 10mA - 0.5 - V

Vz Output Zener-Breakdown Voltage - 15 - V

Truth Table

IN- IN+ CT OUT1 OUT2 FG Mode

H L L H L H Rotating

L H L L H L Rotating

- - H off off - Lockup protection activated

AH292

Document number: DS31049 Rev. 7 - 2

3 of 8

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June 2010