Integrated Voltage Regulators Help Pull Heat Out of Processors

Power-hungry AI chips in data centers are starting to be powered from below, with DC-DC converters placed directly beneath the processor rather than crowded around it on top of the PCB. The closer placement of the power converters means less parasitic resistance and inductance to obstruct thousands of amps of current as it travels through the copper PCB traces. That helps reduce power losses that can add up over over longer lateral distances as well as impedance that can slow down transient response times.

But one challenge in bringing power electronics as close as this to the system-on-chip (SoC) is thermal coupling, said Mukund Krishna, senior manager of product marketing at chip startup Empower Semiconductor (see video above).

High-performance AI chips run hot, and voltage regulators also produce heat when slinging over a kilowatt of power into them. Heat dissipated by the processor impacts the thermal situation in the DC-DC converter — and vice versa — and heat from both sources meets in the ground planes of the PCB.

Better Power Delivery with IVRs

This is one of the issues that Empower tries to tackle with its Crescendo series of integrated voltage regulators (IVRs) shown at APEC 2026. These devices integrate the converter, inductors, and capacitors in a single ultra-thin package.

The startup claimed this allows for faster, more efficient power delivery than traditional DC-DC converters. DC-DCs rely on relatively large inductors and vast clusters of capacitors to smooth out current racing into the processor and prevent voltage droop. These passives limit proximity to the processor.

Empower claims Crescendo can be up to 5X smaller with 20X faster transient response times and 20% better efficiency than board-level designs used to meet the massive current and bandwidth demands of AI chips.

By consolidating the power regulator into a single chip and enabling vertical integration, these IVRs can be positioned much closer together as well as a lot closer to the processor than board-level power architectures.

Crescendo is also modular and scalable: as many as 50 voltage-regulator ICs, each supplying up to 60 A of current, can be connected into a multiphase power converter that delivers up to 3,000 A. The solution steps down a 3.3-V input to the core voltage of the processor, which can be between 0.3 and 1.8 V.

Helping with heat dissipation is the thin form factor of the Crescendo chips. Unlike traditional voltage-regulator modules (VRMs), which put power inductors on top of the power die, the IVRs aren’t as tall. Since heat travels a shorter vertical distance to the cold plate, the devices aren’t as difficult to keep cool.

The higher power density also means the Crescendo platform can be scaled up to higher currents without straying out from under the processor, which would reintroduce the issues of distribution losses and heat.

However, the startup said it can turn down the heat even more by uncovering the underside of the IVR and equipping it with a copper interface that significantly reduces the junction-to-case thermal resistance (θJC) of the device to around 1°C/W. The copper pad helps pull heat out of the PCB and push it into a heatsink or cold plate placed directly under the regulators.

“The reason that thermal resistance matters is because to achieve high power density, you need really good thermals to go along with it,” said Krishna.

At APEC 2026, the startup showed a Crescendo-based vertical power architecture linking 16 voltage regulators to deliver close to 1,000 A to processor operating on a core voltage of 0.75 V. In the demo, each device dissipated 5 W worth of heat from itself and more than 6 W of heat from the board above it.

“So, we’re not only pulling heat out of our device because of the backside thermal solution, but we’re also pulling heat out of the PCB, which is sandwiched between these heat sources,” said Krishna.

Fresh Funding for Fresh Competition

Empower is touting the thermal performance of its IVRs after it raised $140 million of new funding last year to scale up production of the Crescendo platform and prepare for more commercial traction. For instance, Marvell recently announced plans to offer Empower’s pre-validated IVR solutions as part of its business building custom AI accelerator chips, or XPUs, for others. These IVRs are intended to be placed under, adjacent to, or even inside the same package as XPUs.

Empower said Crescendo features 2X faster voltage-droop response than other converter solutions, which allows it to reduce the power consumed by XPUs by up to 15%. Crescendo uses ultra-fast CMOS power transistors based on the same FinFET technology used in GPUs and other advanced logic chips. Thus, it responds faster to load transients without requiring lots of power inductors and bypass capacitors to prevent voltage droop. The faster speeds also help achieve higher processor utilization in a typical AI workload.

Crescendo will ultimately compete with more traditional VRMs from Analog Devices, Infineon, Monolithic Power Systems, Texas Instruments, and the like. Add to these a growing number of startups such as Endura Technologies, Ferric, and Power Lattice developing IVRs to tackle the increasingly tricky issues around AI power delivery.

Said Jack Egan, research analyst at Charter Equity Research, “Many of the large semiconductor players will be allocated the bulk of voltage regulator volumes in the near and intermediate term, while startups, like Empower Semiconductor, will have significant opportunities to compete in the long term. Empower’s strong technological capabilities and engagements with XPU providers position it well for growing adoption of VPD.”