DESCRIPTION
Demonstration circuit 2959A-A is a high efficiency, high
power density hybrid step-down converter. It can deliver
12V/50A with an input voltage from 36V to 60V (up to 65V
during transients). This demo board features PolyPhase®
design using the LTM®4660, which uses an architecture
that merges soft-switching switched capacitor topology
with a traditional step-down converter to provide
superior efficiency compared to the traditional switching
architectures. It offers a high efficiency/high density and
cost-effective solution for nonisolated intermediate bus
applications in power distribution, datacom, and telecom.
The LTM4660 on DC2959A-A always operates in continuous
conduction mode. The switching frequency can be
programmed through a resistor or can be synchronized
to an external clock signal. Due to its current mode control
architecture, excellent current sharing and low output
voltage ripple are achievable in the multiphase configuration.
Other benefits include low EMI emissions due to a
soft-switched front end and reduced MOSFET stress.
The LTM4660 monitors system voltage, current, and temperature
for faults. It stops switching and pulls the FAULT
pin low when a fault condition occurs. An onboard timer
can be set for appropriate restart/retry times. Additional
features include ±1.5% output voltage accuracy over
temperature, a power good output signal, short-circuit
protection, monotonic output voltage start-up, optional
external reference, undervoltage lockout, and internal
charge balance circuitry.
The LTM4660 data sheet must be used in conjunction
with this demo board manual.