Allegro’s new BLDC fan driver lowers data centre energy use

Allegro MicroSystems has launched what it says is the world’s first three-phase BLDC driver IC with integrated power loss brake (PLB) features.

The A89331 code-free, sinusoidal sensorless fan driver is designed to improve thermal efficiency to reduce energy use and data centre costs. It also includes features that can improve safety and reduce the bill of materials in the data centre.

“We created the A89331 in direct response to trends in the server market,” commented Andy Wang, Product Line Engineering Manager at Allegro. “It is the smallest yet most advanced solution for server and data centre cooling fans.”

When server fans malfunction or break, backflow causes them to go into reverse rotation. The other fans have to work harder to compensate for the resulting airflow – increasing power consumption.

The integrated PLB function in the A89331 applies a brake to fans that aren’t working properly. This eliminates the extra power use and increases thermal efficiency – resulting in reduced energy consumption and data centre costs.

The traditional solution to preventing reverse rotation of broken fans is adding external circuitry to function as the power loss brake, but these external components do not fit into 1U fans. The A89331 counters this as it fits both a three-phase BLDC driver and PLB in a 1U fan.

The A89331’s integrated power loss brake also stops fans from spinning when they are disconnected from power to prevent injury.