60-A Digital POL DC-DC Modules Based On SEPIC-Fed Buck Topology
CUI Inc. leveraged its Solus Power Topology, which integrates a conventional buck converter into a SEPIC converter, to drive the new NDM3ZS-60 family of digital point-of-load (POL) dc-dc modules. The single-stage topology uses pulse-width modulation to optimally control one magnetic element, one control switch and two commutation switches. Lower voltage and current stresses coupled with an inherent gate-charge-extraction (GCE) process enables the topology to reduce switching turn-on losses by 75% and switching turn-off losses by 99% on the control FET over conventional buck converters, according to CUI. It also distributes energy delivery into multiple paths, reducing circuit conduction losses by nearly 50%. The compact, 60-A non-isolated modules feature efficiency peaks up to 91.3% at 12 V dc in to 1.0 V dc out, 50% load, and up to 88.5% at full load. CUI says the module is the first to use Intersil’s ZL8800 digital power controller, which helps enhance transient response by responding to a transient load step in a single switching cycle. Zero compensation allows the modules to set optimum stability in real time as conditions change. Input range for the series spans 7.2 to 14 V dc; programmable output ranges from 0.6 to 1.5 V dc.