High step-down ratio enables single-stage voltage conversion in 48V systems

November 20, 2017 // By Christoph Hammerschmidt
Rohm Semiconductor has introduced a DC/DC converter IC that features a particularly high step-down ratio – the device can generate an output voltage of 3.3 or 5V from an input voltage of up to 60V. In 48V systems such as those currently introduced in mild hybrid vehicles, this chip can help to simplify system design and reduce space requirements.

To obtain this high voltage ratio, Rohm’s new BD9V100MUF-C uses the semiconductor manufacturer’s proprietary Nano Pulse Control technology, which leverages high-voltage BiDCMOS processes and ultra-high-speed pulse control to realize an unprecedented on time of just 9 nanoseconds. The technology enables single-stage voltage conversion in 48 V systems; at switching frequencies of 2 MHz the number of parts required is halved, reducing application size and simplifying system design, while high-frequency operation also permits the use of smaller external components, e.g. coils and output capacitors.

Energy savings and environmental performance are the driving force behind constant innovation in the auto industry. Through optimized power distribution, mild hybrid vehicles with 48 V systems achieve significantly lower energy and fuel consumption, which in turn reduces CO2 emissions. Active systems for enhanced comfort in automobiles, such as brake-by-wire or electric power steering, increase the electrical power requirements. In traditional 12 V systems, electrical energy must be transported to loads at a low voltage level, causing increased losses in the wiring harness. The need for thicker copper wires also adds weight, with a negative impact on fuel consumption. The use of 48 V technology cuts the amount of electricity transferred by a quarter, so reducing losses in the wiring.