ROHM Offers a Lineup of 24 Power Supply ICs for AC/DC Converters: Integrated power MOSFET results in the industry’s highest efficiency and smallest form factor

ROHM has recently announced the development of power supply ICs for AC/DC converters in primary power supplies for home appliances and AC adapters. The BM2xxx/F series consists of 24 models that utilize a proprietary low ON resistance SJ MOSFET and feature circuit optimization, resulting in industry-leading efficiency and low noise. In addition, a surface mount type is available in the SOP8 package that contributes to set miniaturization. We are working on expanding our lineup to achieve high efficiency in a wide range of home electronics, including appliances, TVs, and monitors.

AC/DC converters, used to configure the primary power supply in electronic devices, must meet market needs for improved energy and space savings along with greater convenience. Generally, there is a strong demand for power supply ICs in AC/DC converters to be Energy Star compliant and provide high efficiency operation that includes standby power. Also, the increased number of components leads to a larger mounting area, presenting additional challenges regarding design complexity and time.

In response, ROHM utilized power supply technology cultivated from developing LDOs, DC/DC converters, and the like along with discrete transistor analog power technology to develop the BM2Pxxx/F series, optimized for AC adapters, home electronics, and office equipment up to 25W that require high efficiency operation in a compact form factor.

Availability: July 2013 (Samples), September 2013 (OEM Quantities)
Pricing: 100-300yen (Samples)

Key Features

1．High efficiency operation contributes to greater energy savings

In order to improve efficiency a proprietary high performance super junction MOSFET is utilized, while exhaustive optimization of the driver circuitry enabled us to maximize MOSFET performance.

As a result, our products cleared the 86.35% efficiency rating required by Energy Star 6.0. In fact, an efficiency more than 87% is possible by simply replacing conventional products with our ICs (100VAC, 25W applications), while greater than 90% can be achieved through optimization of peripheral components.

2．Improved efficiency also reduces standby power

The internal super junction MOSFET features a voltage resistance of 650V, low ON resistance (just 4.0Ω even with the SOP8 package), low gate charge Qg, and high-speed switching capability.

In addition, standby power consumption is less than 20mW (@100VAC) for a 25W adapter and only 30mW @ 230VAC – significantly less than the 100mW required by the Version 6.0 Energy Star. And even lower consumption is possible by adjusting the peripheral circuitry.

3． Compact package

AC/DC systems typically use a planar-type MOSFET, which is difficult to miniaturize due to problems associated with heat dissipation. In contrast, we use a super junction MOSFET and integrate a number of protection functions, enabling us to offer a variety of package types in the 8W and under class, from conventional DIP7 to surface mount SOP8 (6.2x5.0x1.5mm) that reduces mounting area by 47% for easier design and board layout.

Terminology

• Super Junction MOSFET

A type of power MOSFET that utilizes a three-dimensional depletion spread 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 US by the EPA and the Department of Energy. Target products include PCs, printers, and multifunction devices. It was later adopted in Japan in 1995 by the Ministry of Economy, Trade, and Industry, which implemented an ‘International Energy Star Program.’ The Version 6.0 Energy Star specifications are scheduled to take effect on June 1, 2013.