Diodes AH9279 - Manual

Data Sheet
TWO PHASE DUAL-COIL CMOS SMART FAN MOTOR DRIVER AH9279
Oct. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited
1
General Description
The AH9279 is a most advanced fan control and
drive Hall IC manufactured by special CMOS
process. This IC consists of voltage reference, Hall
sensor, signal amplifier, wave shaping circuit, locked
rotor detector, locked rotor protection and restart
circuit, output drive circuit, etc.. To allow survival in
a harsh environment and in consideration of low cost,
the AH9279 has been designed with many functions
internally, and requires less external components.
When there is no motion for one second, the IC will
detect locked rotor conditions, enter protection mode
automatically and disable two outputs for five
seconds. Then, it will turn on drive current from one
channel for one second. If it still fails to detect fan
rotation, the AH9279 will shut off the outputs for five
seconds again. This sequence will be repeated until
rotation condition is detected and the IC enters
normal operation mode. This function prevents the
chip from overheating and damage due to long time
locked rotor.
The power dissipation decides allowable maximum
ambient temperature. Low power dissipation of
AH9279 and the output MOS
FET power transistor
enable it to be used at ambient temperature up to
125
°C on condition that the drive power is lower than
100mW or drive current is less than 200mA.
The AH9279 is available in TO-94 package.
Features
•
On Chip Hall Sensor
• Built-in Zener Diodes Protection for Output
Driver
• Power Efficient CMOS and Power MOSFET
Drivers Allow 400mA Without Overheating
• 5V and 12V Operation
• High Sensitivity for Switching Symmetry
• Locked Rotor Shutdown and Auto Restart
• ESD Rating: 4000V(Human Body Model)
400V(Machine Model)
Applications
•
Dual-coil Brushless DC Fan
Figure 1. Package Type of AH9279
TO-94