By Gina Roos, editor-in-chief
Allegro MicroSystems has claimed the industry’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 in data centers, reducing energy use and costs. In addition, the PLB features improve safety and reduce the bill of materials (BOM).
When server fans malfunction or break, backflow causes them to go into reverse rotation, which forces the other fans to compensate for the resulting airflow, which increases power consumption, according to Allegro.
Traditional solutions for preventing the reverse rotation require additional external circuitry to function as the power loss brake, which don’t fit into 1U fans, driving the BOM cost up and efficiency down, the company noted. It also requires coding, which increases time to market.
The integrated PLB function in the A89331 applies a brake to fans that aren’t working properly, which eliminates the extra power use and increases thermal efficiency, the company added.
The A89331 solution fits a three-phase BLDC driver and PLB in a 1U fan. Allegro also uses proprietary code-free drivers that eliminate the need for software development and verification.
Other benefits include the capability to run server fans at higher speeds and improve speed control accuracy. The A89331 offers a trapezoidal drive for higher RPMs and improves speed accuracy to ±1.5% @ 25°C.
The A89331 offers a max input voltage operating rating of 18 V with an operating temperature range of -40° to 105°C. The device is available in a 28-contact 5 × 5 mm QFN with exposed thermal pad (suffix ES), and a 20-lead TSSOP with exposed thermal pad (suffix LP). These packages are lead (Pb) free, with 100% matte-tin leadframe plating.
Samples of the A89331 are now available. Request samples here.
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