White Paper: High Performance ZVS Buck Regulator Removes Barriers To Increased Power Throughput In Wide Input Range Point-Of-Load Applications

High Performance ZVS Buck Regulator Removes Barriers To Increased Power Throughput In Wide Input Range Point-Of-Load Applications

Over the past few years, the industry has seen significant improvements in device packaging,
silicon integration and MOSFET technology, yielding highly integrated, compact solutions. While these solutions work well over a narrow voltage range, the efficiency and throughput power tend to drop slightly at modest step-down ratios of 10:1 or 12:1 and fall off dramatically when they are subjected to a wide input range that can be higher, with a step-ratio approaching 36:1. This paper will illustrate the challenges of hard switching in a moderate and high switching frequency environment by comparing simulation models of two designs using the conventional buck regulator topology.

This paper introduces and details the challenges that have existed up to now when attempting to operate the conventional Buck Topology at high input voltage and switching frequency. Operation of a buck converter at high frequency and input voltage is desirable to reduce the overall size of a power system solution so that it could be used to replace dual conversion stages and operate over a wider input range at high efficiency. In order to operate at higher switching frequencies, turn-on losses of the high-side MOSFET need to be reduced or eliminated.

ZVS Buck Topology is presented as the means to achieve the required size reduction without reducing throughput power. A new product, called the PI33XX is introduced that utilizes a Picor high performance silicon controller architecture and contains the necessary features to allow wide input range 8 V – 36 V input to various outputs such as 1 V, 2.5 V, 3.3 V, 5 V, 12 V and 15 V at high throughput power and efficiency. Finally, the same high performance silicon controller architecture can be used to address hard switching applications that are typically done with either Boost or Buck-Boost topologies, yielding significant throughput power and density improvements.

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