Ideas on DC-DC Converters in Magnetic Field LCWG06 Linear Collider Workshop, 9-13 March 2006 Bangalore, India Satish Dhawan, Yale University

Inhibit CMS ECAL: Electromagnetic Calorimeter 80 Amps Power supply for 4 LVR Boards Power 30 meters away 3K Boards x 16 amps = 48 Kamps Magnetic Field 4T in CMS Power Delivery Efficiency < 40 % Front end ASICs 0.25 micron CMOS. 2.5 Volts Next version ~ 0.13 micron CMOS

CMS ECAL K amps 1. Power supply output = 6.3 volts meters cable to LV regulator card. Drop = 2 Volts 3. ST Voltage Regulator drop = 1.8 Volts 4. Delivered output voltage = 2.5 Volts 5. Total Drop = 3.8 Volts 6. Efficiency < 40% 7. Heat load ……

1. Power supply output = 48 volts 2. Feed Line drop < 0.1 Volts 3. DC – DC Converter Efficiency > 85 % ?? 4. Magnetic field = 4 Tesla 5. Radiation Environment WITH DC-DC Converter: CMS ECAL 48 1 K amps

Why DC-DC Converters Close to Load ?? 1. Design Copper leads for voltage drop 2. Vdrop ~ I peak x R 3. Power = (I peak ) 2 x R x Duty Cycle 4. Easier Power Cabling 5. Lower Power Dissipation 6. Lower Copper volume inside Detector

IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 40, NO. 4, APRIL 2005 A 233-MHz 80%–87% Efficient Four-Phase DC–DC Converter Utilizing Air-Core Inductors on Package Peter Hazucha, Member, IEEE, Gerhard Schrom, Jaehong Hahn, Bradley A. Bloechel, Associate Member, IEEE, Paul Hack, Gregory E. Dermer, Member, IEEE, Siva Narendra, Member, IEEE, Donald Gardner, Member, IEEE, Tanay Karnik, Senior Member, IEEE, Vivek De, Member, IEEE, and Shekhar Borkar, Member, IEEE Circuit Research, Intel Laboratories, Intel Corporation, Hillsboro, OR Block diagram of a high-frequency four-phase interleaved dc–dc converter.

Features: 48 Vin VI Chip Converter Up to 100 A / 300 W High density – up to 360 A/in3 / 875 W/in3 Small footprint – 90 A/in2 / 270 W/in2 Low weight – 0.5 oz (14 g) Pick & Place / SMD >92% efficiency at 1.5V 125°C operation 1 µs transient response >3.5 million hours MTBF J-lead package Switching Frequency – 3 MHz Mu =100

Future ??? Should this approach be pursued?