Synchronous boost DC/DC converter IC improves battery life

Today’s portable devices are often driven by single-cell li-ion batteries that deliver an output of approximately 4.2V at full charge. However, a DC/DC converter is needed to boost the voltage when connecting to interfaces requiring 5V output, such as USB, HDMI and audio amps for speakers.

When the remaining battery level is low, the input voltage into the system (battery output voltage) decreases. Utilising industry-leading analogue design technology cultivated over many years have allowed ROHM to deliver stable 5V output even at input voltages as low as 2.5V (down from the conventional 2.7V), extending battery life considerably.

In addition, two operating modes are built in: PWM/PFM mode automatically switches between PFM and PWM based on the load, ensuring up to 90% efficiency across all load regions; and mixing PWM mode which provides higher efficiency than typical PWM at light loads and prevents unwanted audible noise from being generated during switching, making it suited for high fidelity audio systems.

Typically, two or more ICs or one large IC are required in order to obtain an output current of 2A. However, increasing the size of the IC and/or total board area can become problematic, particularly in portable devices that demand smaller components. The BD1865GWL can deliver 5V/2A output in a compact 1.6x1.6mm package, contributing to greater end-product miniaturisation.

The BD1865GWL DC/DC converter IC is available now, priced at $0.43 each in 3,000 unit quantities. An evaluation board is also available.