60-A digital POL dc-dc module sets performance benchmarks

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By eeNews Europe

The NDM3ZS-60 is a non-isolated module that outputs 60 A in ultra low-profile vertical and horizontal packages. The series is the first non-isolated design to incorporate CUI’s patented Solus Power Topology which integrates a conventional buck converter into a SEPIC converter to form a SEPIC-fed buck converter; a single stage topology with one magnetic element, one control switch and two commutation switches that are optimally controlled by pulse-width modulation (PWM).  

With lower voltage and current stresses in the topology coupled with an inherent gate charge extraction (GCE) process, the topology is able to reduce switching turn-on losses by 75% and switching turn-off losses by 99% on the control FET when compared to a conventional buck converter. The Solus Topology further increases total efficiency by distributing the energy delivery into multiple paths, reducing circuit conduction losses by nearly 50%.

The NDM3ZS-60’s topology allows the device to achieve key performance metrics quickly. Efficiency peaks at 91.3% at 12 Vdc in to 1.0 Vdc out, 50% load.  Efficiency remains high up to full load at 88.5%. Transient response is also greatly improved with the SEPIC-fed buck. At 12 Vdc in to 1 Vdc out with a 30 A load step (from 15 A to 45 A) and a 10 A/µs slew rate, peak voltage is 16 mV with typical external capacitance required.

The NDM3ZS-60 is also the first released module to use Intersil’s ZL8800 digital power controller which incorporates a range of advanced digital features. The ZL8800’s ChargeMode Control technology further enhances the module’s transient response performance by responding to a transient load step in a single switching cycle. With zero compensation required, the modules autonomously balance the trade-offs between dynamic performance and system stability on a continuous basis. With this feature, designers are able to bypass the traditional practice of building-in margins to account for factors such as component ageing, manufacturing variations, and temperature, which inevitably lead to higher component cost and longer design cycles. The NDM3ZS’s zero compensation feature allows the module to dynamically set optimum stability in real time as conditions change.

The NDM3ZS-60 series is available with an input range of 7.2~14 Vdc and a programmable output range of 0.6~1.5 Vdc. Additional features include voltage sequencing, voltage tracking, synchronization and phase spreading, programmable soft start and stop, as well as a host of monitoring capabilities. All features are dynamically programmable via PMBus commands or through CUI’s simple, easy to use Novum ACE GUI.
The family is available in three compact configurations, a through-hole vertical version measuring 33.02 (L) X 8.92 (W) X 18.11 (H) mm and a horizontal version measuring 33.02 x 18.11 x 7.44 mm that is offered in surface mount or through-hole configurations. For added flexibility during the development process, the modules are footprint nested to accommodate dual layout needs in the event that design requirements change. Additionally, the NDMZ3S-60 is footprint compatible with 40 A and 50 A digital modules currently available from CUI and other manufacturers, providing up to a 50% increase in power density over existing solutions.

“CUI’s patented Solus Power Topology is a SEPIC-fed buck converter topology and it allows higher power densities, higher efficiencies and faster transient responses so it has a lot of inherent characteristics that take the best of the FET world and the best of the controller world and makes it better,” explained Mark Adams, CUI’s Senior Vice President.  “We have also coupled it with Intersil’s ZL8800 digital power controller and are really pushing some significant limits with the solution.  We are putting 60 A in the same footprint that we currently put 50 A or Ericsson puts 40 A.  That is anywhere between 25 to 50 percent more power in the same exact footprint in a vertical orientation”.

"Our networking customers have hit a ceiling with existing POL topologies as the challenges of powering today’s advanced ICs have increased. Our NDM3ZS-60 addresses these efficiency, power density, and transient challenges head-on."  
Engineering samples are available immediately for select customers.

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