Demonstration circuit 2879A is a high efficiency, high power density hybrid converter. It can deliver 12V/25A with an input voltage from 36V to 60V (up to 65V during transients). This demo board features the LTM4660, 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.
Due to its current mode control architecture, multiple LTM4660s can be operated in a parallel, multiphase configuration with excellent current sharing and low output voltage ripple to enable much higher power applications. Other benefits include low EMI emissions due to a soft-switched front end and reduced MOSFET stress.
The LTM4660 design eliminates the inrush current typically associated with switched capacitor circuits by pre-balancing the capacitors on start-up. The LTM4660 also 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 clock output for multiphase operation, 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.
