Powering AI processors – 48V vertical power delivery changes the game
AI models demand huge current, driving legacy multiphase designs past 50 phases—causing space, thermal, and control limits Vicor addresses
Customer’s challenge
New solid-state X-ray technology allows medical X-ray scanners to be more portable and battery operated, enabling medical professionals to check patients in any location. Medical X-rays typically need a short pulse of high-intensity radiation energy, which can conveniently be stored and supplied to the X-ray diode by a supercapacitor, in this case charged to 28V. Normally the 28V would be sourced from a number of Li-ion batteries in series. However, in a portable application, this type of battery array and charging system is too large and too heavy. The key goals were:
- Find an alternative to heavy and bulky multiple-cell battery solutions
- Fast charging of the supercapacitor requires a high current pulse
- Long battery life to minimize the need for recharging
The Vicor solution
Use of a bi-directional DC-DC converter reduced the battery array to just one 2.7V Li-ion cell, reducing size and weight significantly compared to a typical boost converter solution. In addition, the bi-directional converter delivered higher efficiencies when charging the supercapacitor from a low voltage source, extending battery life.
Key benefits
Key benefits
Ultra-small, lightweight solution (8.6cm2 footprint, 16g weight) compared to a boost converter solution
Unique bi-directional converters (DC-DC transformer) available as standard products
Higher efficiency achieved using low-loss Sine Amplitude Conversion topology
Bi-directional VTM, operating in reverse mode, enabled highly-efficient x12 transformation
A Vicor VTM, operating in reverse, stepped-up the 2.7V input to provide a nominal 32V rail with an efficiency of more than 94%. For the supercapacitor charging circuit, a ZVS Buck-Boost converter regulated the 32V and provided the necessary current limiting. This architecture was accomplished in a footprint of just 8.6cm2. To analyze this power chain, go to Vicor Whiteboard online tool.
Power delivery network
Isolated fixed-ratio
Input: 0 – 60V
Output: 0 – 55V
Current: Up to 130A
Peak efficiency: 97%
As small as 22.83 x 8.52 x 4.9mm
Non-isolated regulated
Input: 8 – 60V
Output: 10 – 54V
Power: Up to 150W continuous
Peak efficiency: 97%
10.5 x 14.5 x 3.05mm
Resources
Resources for the design engineer
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