The BM2xxx/F series comprises 24 models utilizing a low-on-resistance SJ MOSFET with circuit optimization, resulting in industry-leading efficiency and low noise. A surface-mount option in an SOP8 package is also available, further contributing to miniaturization. ROHM is working to expand its product line to achieve high efficiency across a wide range of home electronics, including appliances, televisions, and monitors.
AC/DC converters, used to configure the primary power supply in electronic devices, must meet market demands for improved space and energy efficiency, along with greater convenience. In general, there is strong demand for integrated circuit power supplies in AC/DC converters to comply with Energy Star regulations and provide high-efficiency operation, including standby power. Furthermore, the increased number of components leads to a larger assembly area, which presents additional challenges related to design complexity and time.
In response, ROHM uses power technology developed in DC/DC LDO converters and the like, along with discrete transistor analog power technology to develop the BM2Pxxx/F series, optimized for AC adapters, household appliances and office equipment up to 25W, which require high-efficiency operation in a compact format.
Availability: Samples are available now, OEM quantities available from September 2013
Key Features
1. High-efficiency operation that contributes to greater energy savings.
To improve efficiency, an original high-performance MOSFET with a "super junction" structure is used, while comprehensive optimization of the driver circuitry allowed the company to maximize the MOSFET's performance.
As a result, ROHM products achieved the 86.35% efficiency rating required by Energy Star 6.0. In fact, an efficiency of over 87% is possible simply by replacing conventional products with ROHM integrated circuits (100VAC, 25W applications), while over 90% can be achieved through optimization of peripheral components.
2. Improved efficiency also reduces standby power consumption.
The internal "super-junction" MOSFET offers a 650V voltage withstand and low on-resistance (only 4.0Ω even with the SOP8 package), low gate load (Qg), and high-speed switching capability.
Furthermore, standby power consumption is less than 20mW (@ 100VAC) for a 25W adapter and only 30mW @ 230VAC – significantly less than the 100mW required by the Energy Star 6.0 version. Even lower consumption is possible by adjusting the peripheral circuitry.
3. Compact Packaging:
AC/DC systems typically use a planar MOSFET, which is difficult to miniaturize due to heat dissipation issues. In contrast, ROHM uses a "super junction" MOSFET and integrates a range of protection features, allowing the company to offer a variety of 8W package types, from the conventional DIP7 to the surface-mount SOP8 (6.2x5.0x1.5mm), which reduces the mounting area by 47% for easier board design and layout.
Terminology
• MOSFET "Super Junction"
A type of power MOSFET that uses an extended three-dimensional reduction for lower switching loss than conventional products.
• PWM (Pulse Width Modulation)
A modulation method that lengthens and shortens the output time of the pulse signal to control current or voltage.
• Energy Star:
An international standard for energy efficiency in consumer products, established in 1992 in the U.S. by the EPA and the Department of Energy. Target products include PCs, printers, and multifunction devices. It was subsequently adopted in Japan in 1995 by the Ministry of Economy, Trade and Industry, which launched an "International Energy Star Program." Version 6.0 is currently under review.
