Theses›Datacentre & AI compute›Converter plane cooling

Converter plane cooling

The power-converter plane is a second thermal path with no cold plate on it

  • Early
  • $7.6B by 2035

The call, a draftThe power converter under an AI accelerator is turning into the hardest heat problem in the package, and nobody has picked the fix yet. The window is early, though channels etched into the substrate already work in the lab.

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Fig. 1The balance. Drivers and catalysts against restraints, each block sized by its weight; catalysts hang dashed because they have not happened yet, sized by their odds. It tips toward the drivers.
  1. D1Accelerator power climbs from 1.0-1.2kW on B200 to about 3.6kW on Rubin Ultra, and with about 14% of it lost in conversion, the heat on the converter plane triples with it.
  2. D2Conversion is moving under and into the package on dated schedules: Vicor's second-generation vertical power ramps in H2 2027, TSMC puts an integrated regulator inside CoWoS-L in 2028, and ADI is buying Empower for $1.5bn.
  3. D3Height is the gate at the converter plane, which rules out cold plates, vapour chambers and thick interface pads and leaves a 0.5-10 micron film as close to the only thing that goes in.
  4. R1Channels etched into the substrate already take a 1kW converter block from over 110C to about 84C at 1.6 g/s with pumping power under 0.1% of the processor's, and they reached the literature before any material did.
  5. R2Nobody has published what a vertical power module spends on thermal materials, so the size of the slot is an estimate built from adjacent bill-of-materials lines.
  6. R3The 2mm height limit comes from one wafer-scale architecture, and Infineon's TDM2454xx module is 5mm tall, so the gate is softer in merchant modules than the headline suggests.
  7. R4When the converter moves inside the package, TSMC or the packaging house takes the thermal decision along with it.
  8. C1A backside vertical-power platform passes about 1M accelerators a year, led by Vicor's second-generation ramp with a hyperscaler and two OEM programmes from late 2027.31 Dec 2028
  9. C2A named accelerator vendor or converter maker states on the record which thermal approach it has chosen for the converter plane.30 Jun 2027
  10. C3A shipping accelerator power module specifies CVD diamond or another spreader above 1,000 W/mK inside the module.31 Dec 2028
What would prove itdated tests, open and resolved
202720282029today1234567predictionswatch 202720282029today1234567predictionswatch
Fig. 2Each ring is a dated test: dashed while open, struck through when overdue, ticked or crossed once resolved.
  1. 1No AI-accelerator power module or vertical-power-delivery product announced between 6 Nov 2026 and 31 Jan 2027 specifies a diamond, graphene or other >1000 W/mK spreader at the converter plane.Jan 2027 · open
  2. 2An accelerator vendor or converter maker names its converter-plane thermal approach on the record.Jun 2027 · open
  3. 3Vicor's second-generation vertical power ramps into hyperscaler and OEM production.Dec 2027 · open
  4. 4By end-2028 at least one shipping AI-accelerator power module publicly specifies a high-conductivity heat-spreading material — CVD diamond, a >1,000 W/mK composite, or equivalent — inside the module, rather than relying on substrate microchannels, module case conduction or the board alone.Dec 2028 · open
  5. 5The kill line.Dec 2028 · open
  6. 6TSMC's integrated voltage regulator in CoWoS-L reaches production, moving the converter into the package.Dec 2028 · open
  7. 7Microchannel-cooled vertical power in two or more shipping platforms with no merchant material alongside closes the slot.Dec 2028 · open
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