It’s not easy being tasked with designing a “better” DC/DC buck converter, which must transform a lightly regulated DC voltage into a tightly regulated source for motors, industrial equipment, and communications infrastructure; as always, the objective is higher efficiency, but without any penalty in size, complexity, or performance.
The efficiency mandate is driven by multiple factors: The desire to use less energy and thus reduce the direct cost of the sourced electricity; the need to cut the system cooling requirements; the promise of greater long-term reliability due to cooler operation; operation over a wider minimum/maximum output-current range, with minimal dissipation in light-load conditions; increasingly stringent regulatory mandates on efficiency across the entire load range, and going down into lower end of the load range as well.
The first step to efficiency in industrial and datacomm infrastructure applications is to use higher voltages such as 48 VDC to reduce IR drop and I2R losses. Yet the efficiency quest can’t accept any compromise in basic specifications such as accuracy and line/load regulation. Further, these applications are in electrically harsh environments, so any converter must gracefully handle unavoidable events such as lightning-induced transients.
To meet these needs without getting mired in a circuit-topology swamp, ROHM Semiconductor is leveraging its IC design capabilities to take the already high efficiency of buck converters further. Rohm is achieving this without compromising performance or adding to circuit complexity or the bill of materials (and even reducing it). Rohm’s latest entry into the higher-voltage buck-converter arena is an IC that handles inputs from 12V to 76V, while delivering up to 3A at a user-set output voltage, and includes the critical high-voltage MOSFET.