First eFuse product suitable for server applications

04-02-2022 | Alpha and Omega Semiconductor | Passives

Alpha and Omega Semiconductor Limited has released its initial eFuse product for sub-power rails in server applications. The AOZ18101DI series are 5A eFuses in a compact 3mm x 3mm DFN package. The new products use advanced co-packaging technology, incorporating a high-performance IC with protection features and its latest high SOA Trench MOSFET. The new devices provide low RDS(ON) (20mOhm) back-to-back MOSFETs to isolate the load from the input bus when the eFuse is off.

Due to high-reliability needs for server products, all critical power rails are monitored and protected by an eFuse device to protect the main power bus from interruption due to abnormal load under fault conditions. The eFuse constantly monitors the current flowing through the power switch. If the current is higher than the set limit, the switch will limit the current to the maximum permitted. If the high current load continues, the switch will finally turn off, protecting downstream loads from damage, thus acting as a fuse.

The devices' integrated True Reverse Current Blocking (TRCB) for the fault conditions that the power rail at VOUT is higher than the main bus at VIN, enabling no reverse current. Control for external blocking FET is also offered for designs currently in production by providing a drop-in replacement to existing eFuse products needing external FETs to implement the TRCB feature. For loads with high inductive kickback such as hard disc drive and server fans, the AOZ18101DI-03 and AOZ18101DI-04 offer the TRCB feature disabled to avoid shut down the input power bus due to a reverse current. All devices provide startup SOA management and other protections permitting for glitch-free power-up of the system or hot plug into the 12V backplane.

“High-reliability systems such as servers and storage require input bus protection. Traditional designs use a hot-swap controller and an external discrete FET. Still, this solution is increasingly dropped in favour of a more compact solution offered by an eFuse. AOS’s ability to combine TrenchFET technology with leading IC design enables compact, robust eFuse products,” said Peter Cheng, Power IC senior marketing director at AOS.

By Natasha Shek