Synchronizable POL converters beat the noise
By Margery Conner, Technical Editor -- EDN, April 26, 2007
Power subsystems that use a DPA (distributed-power architecture) usually have several independent power modules throughout the system, providing different voltages and currents and probably switching at different frequencies. These differing frequencies can cause significant noise problems for the system. The IBA (intermediate-bus architecture) is even more susceptible to module switching noise. They have more switching modules with higher switching currents resulting from the lower voltages of their nonisolated POL (point-of-load) converters. Add to this the fact that the power subsystems often mix power converters from different manufacturers, and a very noisy power environment can result.
To address these problems, the NAT1vvvvXcc family of POL converters from NetPower includes a synchronization option to allow all POL converters in a system to operate at the same switching frequency and eliminate beat frequencies. In addition, you can phase-shift the converters’ clocks, allowing the converters to operate in an interleaved mode and further reduce switching-frequency noise. The synchronization also lets designers avoid critical frequencies that may interfere with the system’s operation or modulate the switching frequency to eliminate or manage system EMC (electromagnetic-compatibility) problems. The input range for the modules is 8.5 to 18V, and the output range is 0.75 to 8V with a 12A ($9.30) or a 20A ($11.50) output current.
