16 phase power regulator for Nvidia AI server

Alpha and Omega Semiconductor (AOS) has launched a 16 phase, two rail controller for the latest OpenVReg16 (OVR16) specifications from Nvidia for AI server designs.

The AOZ73016QI controller design is based on the company’s high performance, proprietary AOS Advanced Transient Modulator (A2TM) control scheme. As well as supporting all the basic requirements of the OVR16 specification, the controller adds RDS(on) and DCR sensing for current monitoring and current balance (see below).

This allows the controller to support both DrMOS and Smart Power Stages (SPS) to deliver a complete AI server and graphic card power solution along with increased design flexibility.

The company previously launched the first four phase PWM controller for the latest Nvidia Blackwell GPU.

The AOZ73016QI digital PWMVID architecture with differential remote sensing achieves 0.5% regulated VOUT accuracy to provide current balance at all load conditions as well as during fast load transients, which is a critical requirement for power-hungry AI and graphics SoCs that demand over several thousands of amps at peak current. It also handles phase doubling or tripling without the addition of a phase doubler so a single controller can support up to a 48-phase design.

Pairing with AOS trench MOSFET-based DrMOS and SPS power stages in an AI server design boosts efficiency and cuts thermal requirements, saving several hundred watts of power during high transient current events. These transients can last for a few 100s of microseconds and up to 1 millisecond when the SoC draws peak power.

Each of the AOS 5 x 5 DrMOS power stages dissipate 14W lower power loss during these peak current events compared to other designs.

The AOZ73016QI also supports an accurate RDS(on) sensing scheme, which uses power stage low side MOSFET RDS(on) sensing, thus enabling the use of low DCR inductors to help boost system efficiency. The device’s automatic phase management (APM) and auto discontinuous mode (DCM) power saving features extend its usability to graphics cards and gaming laptops.

The AOZ73016QI offers full programmability via the PMBUS interface and is also AVS bus compliant. The device features digitally programmable voltage and current regulation loops minimizing the external components required to implement a solution. It supports electronic control system (ECS) programmability with ability to update configuration in the field, and to pre-program up to six configuration settings with a pin-strap selection.

“AOS has a long history of developing leading-edge personal computing, server and datacenter solutions. The launch of our successful AOZ73016QI 16-phase controller for OVR16-based designs is the culmination of several years of R&D investment in multiphase controllers. Developed in close collaboration with our customers’ system architects, the AOZ73016QI is a robust, reliable power solution for more advanced AI servers. Plus, the design flexibility afforded by the AOZ73016QI helps lower TCO for next generation AI servers,” said Ralph Monteiro, Sr. VP, Power IC and Discrete Product lines at AOS.

The AI server controller supports PWMVID, PMBus and is AVSBus compliant and has a user friendly GUI for compensation and configuration with minimal external RC components and a 200kHz to 1MHz programmable switching frequency.

The AOZ73016QI is immediately available in production quantities in a QFN7x7-56L package with a lead time of 12-16 weeks at $4.00 in 1,000-piece quantities.