ROHM Develops BD1865GWL...Achieving High Efficiency with Proprietary Mixing PWM Mode

ROHM Co., Ltd. announced the development of BD1865GWL, a compact, highly efficient, high-power step-up DC/DC converter that operates from a single-cell lithium-ion battery for smartphones and tablets.

The BD1865GWL, suitable for mobile devices equipped with USB and HDMI terminals, applies analog design technology to enable ultra-low voltage operation down to a minimum of 2.5V during battery discharge in mobile devices requiring miniaturization and extended battery life. As a result, the company explained that battery operating time is extended compared to conventional 2.7V products.

Additionally, it incorporates two operating modes: PFM/PWM mode and ROHM's proprietary Mixing PWM mode, and when selecting PFM/PWM mode, it achieves high efficiency of the 90% class across all load ranges.

When Mixing PWM mode is selected, it prevents ringing caused by switching noise that is critical in audio applications. Furthermore, with a single compact IC of 1.6x1.6mm, it can handle a maximum output current of 2A, contributing to miniaturization of applications.

This product began mass production from December 2015 with a production capacity of 500,000 units per month (sample price: 200 yen/unit). The front-end manufacturing is conducted by ROHM Hamamatsu Co., Ltd. (Shizuoka), and back-end manufacturing by ROHM Apollo Co., Ltd. (Fukuoka).

Product Development Background

Smartphones and tablets use lithium-ion batteries with an output voltage of approximately 4.2V at full charge. Meanwhile, USB, HDMI, and audio speakers mounted in these applications operate at 5V, so a step-up DC/DC converter that boosts the battery output to 5V is essential for operation.

Since mobile devices prioritize miniaturization and extended battery life, further miniaturization and higher efficiency are required at the component level. However, existing 5V output step-up DC/DC converters have lacked products that satisfy all conditions—compact size, high efficiency, low-voltage operation, and high-current capability—at a high level.

Product Features

1. Contributes to Extended Battery Life through Ultra-Low Voltage Operation at Minimum 2.5V

As battery capacity decreases, the battery output voltage, which is the system input voltage, gradually declines. This new product applies analog design technology accumulated over a long period to enable 5V output even at a low input voltage of 2.5V. With minimum 2.5V support, battery operating time increases compared to standard products.

▲High-efficiency PFM/PWM mode and Mixing PWM mode are both incorporated.

2. Realizes High-Efficiency, High-Performance IC with Two Operating Modes

PFM/PWM Mode: This mode automatically switches between PFM and PWM in response to load variations, achieving high efficiency of the 90% class across all load ranges. It is optimal for applications such as smartphones and tablets where mode switching is abrupt and efficiency is critical.

Mixing PWM Mode: This mode uses ROHM's proprietary control method to achieve higher efficiency even at light loads compared to conventional PWM mode. Additionally, it suppresses audible noise and prevents ringing, making it suitable for applications that prioritize sound quality, such as audio devices.

3. Realizes High-Power 5V/2A Operation with Compact Package

When realizing 2A output current, there is typically a problem requiring two ICs or an increase in IC size itself. This product achieves a maximum output current of 2A with a single compact IC of 1.6x1.6mm (when 5V output voltage is set), contributing to miniaturization of mobile devices.