Automotive primary DC/DC converters for stable operation

In recent years, the electrification of vehicle systems has increased. Combined with the limited amount of power available, this trend emphasises the need for lower power consumption. At the same time, the output voltage from the batteries and generators can vary widely, demanding a versatile power supply solution.

With conventional power supply ICs, it is difficult to achieve both fast load responses to ensure stable operation and high efficiency in power conversion, contributing to greater energy savings. The new product adopting original advanced power supply technology, Nano Pulse ControlTM, enables high speed operation at 2.2MHz that will not interfere with the AM radio band (1.84MHz max.) while achieving high step-down ratio. It is an optimum technology for automotive applications.

The BD9P series ensures stable operation during battery input voltage fluctuation, reducing output overshoot to less than 1/10th compared to conventional products. This eliminates the need for additional output capacitors typically required to reduce overshoot voltages. In addition, adopting a new control method makes it possible to achieve both, high efficiency and fast load response (which are in a trade-off relationship).

The DC/DC converters offer a 92% power conversion efficiency at heavy loads (at 1A output current), but also 85% efficiency at light loads (1mA), and thus achieve efficiency across the entire load range. This reduces power consumption, which leads to a reduction in CO2 emissions, and the parasitic discharge of the battery is also reduced.

Furthermore, combining the new product with the BD9S series of secondary DC/DC converters cascaded to the subsequent stage allows users to configure faster, more efficient automotive power supply circuits. Reference designs are also available on ROHM official website. Utilising reference boards, tools, and ROHM’s free web simulation tool ‘ROHM Solution Simulator’ it is possible to perform simulations close to actual conditions, significantly reducing application design resources.

ROHM is committed to support the evolution of vehicles by developing products that contribute to lower power consumption and higher system reliability.