Ideas on DC-DC Convertersin Magnetic Field

LCWG06 Linear Collider Workshop, 9-13 March 2006Bangalore, India

Satish Dhawan, Yale University

Inhibit CMS ECAL: Electromagnetic Calorimeter80 Amps Power supply for 4 LVR BoardsPower Supply @6.3V 30 meters away3K Boards x 16 amps = 48 KampsMagnetic Field 4T in CMSPower Delivery Efficiency < 40 %

Front end ASICs 0.25 micron CMOS. 2.5 VoltsNext version ~ 0.13 micron CMOS

CMS ECAL 2.5 Volts @ 48 K amps

1. Power supply output = 6.3 volts2. 30 meters cable to LV regulator card. Drop = 2 Volts3. ST Voltage Regulator drop = 1.8 Volts4. Delivered output voltage = 2.5 Volts5. Total Drop = 3.8 Volts6. Efficiency < 40%7. Heat load ……

1. Power supply output = 48 volts2. Feed Line drop < 0.1 Volts3. DC – DC Converter Efficiency > 85 % ??

4. Magnetic field = 4 Tesla5. Radiation Environment

WITH DC-DC Converter:CMS ECAL 48 Volts @ 1 K amps

Why DC-DC Converters Close to Load ??

1. Design Copper leads for voltage drop2. Vdrop ~ Ipeak x R3. Power = (Ipeak)2 x R x Duty Cycle4. Easier Power Cabling5. Lower Power Dissipation6. 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 97124

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

Features:48 Vin V•I 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 MHzMu =100

Future ???

Should this approach be pursued?