The LM2639 provides an attractive solution for power supplies of high power microprocessors (such as Pentium II?,
M II?, K6?-2, K6?-3, etc.) exhibiting ultra fast load transients.
Compared to a conventional single-phase supply, an
LM2639 based multi-phase supply distributes the thermal
and electrical loading among components in multiple phases
and greatly reduces the corresponding stress in each component.
The LM2639 can be programmed to control either a
3-phase converter or a 4-phase converter. Phase shift
among the phases is 120° in the case of three phase and 90°
with four-phase. Because the power channels are out of
phase, there can be significant ripple cancellation for both
the input and output current, resulting in reduced input and
output capacitor size. Due to the nominal operating frequency
of 2 MHz per phase, the size of the output inductors
can be greatly reduced which results in a much faster load
transient response and a dramatically shrunk output capacitor
bank. Microprocessor power supplies with all surface mount components can be easily built.