Is Monolithic Power System (MPWR US) a Short? – The GB200 Power Module War

Following my previous article on the PCIe topology of NVIDIA GB200 (Astera Labs (ALAB US) – How Large is the GB200 Content Opportunity?), today I'll discuss another important area of GB200: the power modules, as well as Monolithic Power Systems (MPWR US), a power management IC company listed on the U.S. stock market that's been gaining a lot of attention from investors lately.

First of all, we should understand that the GB200 power modules are divided into three different steps: AC-DC, 48V-12V DC-DC, and 12V-1V DC-DC.

Step One: In a data center, AC power (typically between 180V-305V, though varying by country) is first converted to 48V DC through the power supply units (PSUs) on the GB200 racks. A standard GB200 NVL72 rack has six rows of power shelves—three at the top and three at the bottom of the rack（see graph below）. Each power shelf is 1U in height and contains 6 PSUs, giving a total of 6 x 6 = 36 PSUs per rack. Each PSU provides 5.5kW of power, so the total power supplied by all PSUs together is 5.5 x 36 = 198kW. The PSU suppliers are Delta Electronics (primary supplier) and Lite-On, with China-based Megmeet also undergoing verification.

Some readers may wonder here: since the GB200 NVL72’s total power consumption is 120kW, why does a rack require 5.5 x 36 = 198kW of PSU capacity? The reason is that the 5.5kW represents each PSU's maximum load, and for redundancy purpose, PSUs are typically provisioned at 50-60% of their maximum load. This redundancy design justifies having 198kW of PSU capacity for the 120kW- GB200 NVL72 rack.

Step Two: Once the 48V DC enters each compute tray, the voltage is then stepped down to 12V through a power module. There are two module options here: NVIDIA uses IBC (Intermediate Bus Converter) module on its DGX servers, while the latest GB200 servers use PDB (Power Distribution Board) module. Delta Electronics recently disclosed that they lost some content in the GB200’s power module, which refers to this shift from the IBC module to the PDB module.

In simple terms, IBC module is a set of DC-DC converters. A traditional DGX server has 8 IBC modules per compute tray, each corresponding to one SXM module (i.e. one GPGPU), priced around ~$60. The B200 DGX server will still use IBC modules, though at a slightly higher price (~$70), due to supporting the 1.2kW B200 GPU (compared to the 0.7kW of the H100/H200 GPU). Delta, Emerson, and Flex are the main IBC suppliers here.

For the GB200, NVIDIA switched to the newly designed PDB module. Each compute tray contains an 8kW PDB module, which is made up of two 4kW DC-DC converters（see diagram below）. Each PDB module costs around $250, supplied exclusively by Renesas. Monolithic Power Systems has long sought to enter the PDB space but has yet to succeed; the reasons for this will be detailed later.

After covering the PSU, IBC, and PDB, we come to Step Three: the VRM (Voltage Regulator Module) on the Bianca board, which is responsible for converting 12V to 1V. Here, the main supplier is Monolithic Power Systems (MPS). In the paragraphs below, I’ll discuss MPS’s products used in the GB200 Bianca board, its content dollar, market share, and upcoming competition.