Issue link: https://resources.mouser.com/i/1505196
mouser.com/vishay / 15 Scalability Reaching higher output power is possible by paralleling several phases, and there are some benefits to using this approach. Efficiency drops in light-load mode, and using one buck regulator at maximum efficiency is better than using two phases at partial load. Furthermore, the size of the input buffer capacitors can be reduced when operating with interleaved DC/DC converters in parallel. If the same load is supplied with several phases, the output capacitors can be smaller and the intervals without power delivery can be shorter. Finally, the redundancy of parallel phases can ensure higher reliability. When using parts in parallel, designers need to consider that monitoring the current per phase is necessary and important in ensuring a balanced load across all the individual phases. For these high output currents, we typically find that shunt resistors can help ensure an equal load per phase, but are not needed for precise evaluation of the current in multiphase converters, as the DC resistance (DCR) of IHLP inductors is precise enough. While standard inductors offer DCR tolerances of ±5%—which is related to the minimum variance of their wire diameter—Vishay can offer tolerances down to ±1%. Vishay performs 100% end-of-line testing on its inductors and also screens their DCR, making it simple to implement a binning procedure. While Vishay's inductors will experience some drift due to temperature coefficient of resistance (TCR), all inductors in the converter will be running at a similar temperature, so the differences between them will be negligible as long as they have the same initial DCR. In the case that the absolute value of current is needed, a current sense resistor can be implemented. To keep losses low, a low- ohmic-sensing resistor with a resistance in the range of a few milliohms is required. Here, Vishay's Power Metal Strip resistors are the technology of choice, as they offer high stability over time and temperature for precise regulation. Kelvin terminal plus long side termination as offered by the WSKW0612 is an ideal choice. Outlook and Inductor Roadmap Vishay is one of the manufactures with the widest variety of powdered iron core blends. One example is the so-called -8A material, offering up to 180°C temperature capability being important of exhaust gas treatment electronics. Upcoming materials will have a tighter hysteresis curve, to reduce AC losses even further. Engineering samples of this brand-new material are already available on request at the factory. Moreover, Vishay offers the option of semi-customized coils with rectangular cross-section for both higher current capability and reduced DCR. These parts are produced on fully automated lines and push the boundaries of SMD components to higher power for filters and storage inductors in applications such as EV charging infrastructure, solar inverters, and welding machines.