AN4192 Datasheet, PDF (1/47 Pages) STMicroelectronics – In the latest generation of CPUs for modern desktop and notebook platforms

AN4192
Application note
Power MOSFETs:
best choice guide for VRM applications
By Filadelfo Fusillo, Filippo Scrimizzi
Introduction
In the latest generation of CPUs for modern desktop and notebook platforms, the VRMs
(voltage regulator modules) must have some specific features in order to reach high
performance in terms of power management. This target can be reached by analyzing all
the design parameters and their optimization, with a particular focus on the MOSFET
electrical characteristics and configuration.
The power stage must deliver very low core voltage (typically 1.2 V - 1.3 V) to the CPU at
high current levels (up to 160 A), with ever-increasing switching frequencies (up to 500 - 700
kHz). In order to match these requirements, the basic topology used in the VRMs is the
“multiphase synchronous buck converter”, which typically steps down to 12 V input voltage,
providing the desired core voltage.
November 2012
Doc ID 023820 Rev 1
1/47
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