Ultra-compact high efficiency power supplies for automotive applications

Paul Boughton

ROHM has announced the development of compact, high efficiency power supplies designed to drive DDR memory, microcontrollers, and other components in car applications.

The BD905xx series integrates a phase compensation circuit and feedback resistor, reducing the number of external parts considerably compared with conventional power supply ICs. This simplifies design load and contributes to end-product miniaturisation.

In recent years the increasing popularity of electric and hybrid vehicles has led to more sophisticated electronic systems and a greater demand for microcontrollers and memory.

Conventional LDO regulators are commonly used, but they feature poor efficiency and cannot meet higher current demands. As a result, DC/DC converters, which provide greater efficiency and higher current-handling capability, are becoming the preferred solution.

However, they are not without their drawbacks, which include more external parts and consequently a larger mounting area, increasing circuit design complexity significantly. With the trend towards improved performance and decreasing model cycles in the automotive industry comes a need for easier-to-use, high efficiency power supply ICs that lighten the design load and minimise mounting area.

A primary factor in the number of external components used with power supply ICs is the phase compensation circuit required to maintain a stable output voltage. Normally external capacitors and resistors are used to set the desired characteristics. However, ROHM was able to successfully optimize the phase compensation circuit internally, reducing parts count by 80 per cent and contributing to more compact automotive systems. In addition, phase compensation adjustment, which is a common problem with power supply designs, is no longer required, shortening design time significantly.

For more information, visit www.rohm.com/eu