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

2. Inhibit CMS ECAL: Electromagnetic Calorimeter 80 Amps Power supply for 4 LVR Boards Power Supply @6.3V 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

4. CMS ECAL 2.5 Volts @ 48 K amps 1. Power supply output = 6.3 volts 2. 30 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 ……

5. 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 Volts @ 1 K amps

6. 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

7. 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 97124 Block diagram of a high-frequency four-phase interleaved dc–dc converter.

8. 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

9. Future ??? Should this approach be pursued?