The Ideal Situation：Family of Versatile Lineup of Products

With a view toward building a great family of DC/DC converters, ROHM is developing a wide variety of DC/DC converter ICs. The DC/DC converter comprises several types, including a synchronous rectifier type, and each type includes several control methods. ROHM’s DC/DC converter family is intended to provide “the best fit for each application”, offering a slew of advantages.

Designing a DC/DC converter involves the selection of a power supply IC through consideration of various requirements, including the transient response, switching frequency, size, and cost, beyond such input/output conditions as the input voltage, output voltage, and load current. Thus, the fact of life is that given the same set of input and output conditions, no single power supply IC can fulfill all the performance requirements. For this reason, the designer looks for a power supply IC that satisfies the requirements imposed by the equipment for which power is to be supplied, and designs circuits specific to each set of requirements. There may be times when an IC that snugly fits into the design requirements; most of the time, however, the designer performs the maximum possible extent of optimization while accommodating needs for making compromises, all of which involves the expenditure of enormous amount of time and effort.

ROHM’s family of DC/DC converters is intended to provide a set of products which, first of all, provides an “optimal solution” to a given set of requirements. The chart below illustrates an overall organization of the currently available family of products. There are different types of products by scheme and control method. In working with the family, the designer selects a scheme with performance characteristics that satisfy a given set of requirements, and narrows the choice by zeroing in on that which is required in terms of input and output conditions.

I suspect that in situations where the lineup is not extensive enough, there may be more than a handful of designers who have had an experience where, after searching extensively, no just-right IC was found and were forced to look for offerings from other manufacturers. An ideal situation would be the availability of products from a single source that fulfills all the performance requirements.

This is a question relevant not only to designers, but also to supply chain management. In terms of procurement, components making up a product purchased from an extensive list of manufacturers mean an increased level of complexity of operations and management, resulting in unwitting increases in cost. On the other hand, there is a limit to how much flexibility you can have in selecting components in accommodating the needs of procurement. If most of components for a given power supply IC can be procured from a single manufacturer, for example, it would be possible to save the required amount of labor despite the larger number of components that must be obtained.

［BD9x family system chart］