Actively Managed Storage Capacitor Offers Host Of Benefits In AC-DC And DC-DC Applications

Focus:

Modern digital loads can slew at rates in excess of 100 A/μs. Often these extremes are handled by enabling and disabling multiple parallel power stages or by using new, faster power switches and sophisticated controllers. But regardless of how the output regulation is accomplished, the peak currents and edge rates required continue to rise, and the ratio of peak to average current will rise as well. To keep a point-of-load converter (POL) operating properly, a large amount of input filter capacitance is required to absorb the severe edges. The intermediate power supply feeding the POL must then drive a highly capacitive load, which is an invitation to instability when using most control methods. The high edge rates also complicate the design of the PDN. This article explores an alternative approach to POL design that reduces the input filter capacitance required in the face of fast slewing loads, while also improving other aspects of converter performance. This approach is based on a proprietary technology known as the Compound Converter. The article begins by reviewing the principles of operation of the Compound Converter as originally applied to ac-dc power supplies, then describes its application to buck converters and the performance benefits associated with this technology. The improved buck converter performance is demonstrated with a simulation of input current variation as a function of load current transients.

What you’ll learn:

• How to understand the operation of Compound Converter technology as applied to dc-dc converters
• How to reduce input filter capacitance requirements in dc-dc converter applications
• How to add input current regulation to buck converters

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Author & Publication:

Tom Lawson, CogniPower, Malvern, Penn, How2Power Today, Nov 15 2014

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