Tech Insights

Developments in the AC-DC External Power Supply Market

December 05, 2014 by Richard Ruiz

Led by a number of traditional applications within the communications, computers and consumer segments as well as a number of emerging applications, the

Led by a number of traditional applications within the communications, computers and consumer segments as well as a number of emerging applications, the outlook for the external ac-dc power supply market is expected to remain strong over the next several years increasing from $10.7 billion in 2014 to $14.9 billion in 2019, a compounded annual growth rate (CAGR) of 6.9%. Although considered one of the more conservative markets with little change in technology when compared to the embedded ac-dc and dc-dc power supply markets, external power supplies are poised to experience a number of significant opportunities and developments in technology and materials over the next several years.

One of the more interesting opportunities for external power is the emergence of digital power. Traditionally, external ac-dc power supplies have not been considered one of the “best” markets for digital power management and control. Composed of adapters and battery chargers primarily for portable devices, they are not part of the high-end, distributed power systems, which are better suited to digital control. However, the “added functionalities” that enable increased efficiency (and thus meet certain rating systems and regulations) are starting to open this market for digital power management, particularly at the IC level.

As an example, CamSemi offers the C2160 PSS controller ICs that are aimed at high-volume, universal input application rates at 1W to 8W, including chargers for mobile phones, digital cameras, handheld games and other portable devices, along with external power adapters. These devices are designed to help manufacturers comply fully with the latest efficiency requirements, including the 5-star rating system for mobile phone chargers. The key to the PSS controllers’ performance is a proprietary, patented method of measuring the circuit’s output voltage and current level.

Drivers for digitally controlled external ac-dc power supplies are coming primarily from standards and regulations mandating stricter power supply requirements. With the emphasis on increased energy efficiency, manufacturers have the flexibility to offer power adapters that can communicate changes in power requirements, such as higher or lower voltage, or to shut off completely when not in use.

Regulators in the both the US and the European Commission (EC) have proposed minimum efficiency requirements for offline power supplies. In fact, the EC’s Integrated Product Policy (IPP) program and the world’s top five cellphone makers have introduced a voluntary five-star energy rating system for mobile device chargers, making it easier for consumers to determine which ones use the least energy. This rating system covers all chargers currently sold by Nokia, Samsung, Sony, Ericsson, Motorola and LG Electronics, and ranges from five stars for the most efficient chargers down to zero stars for the units consuming the most energy.

There is also an opportunity to use USB 3.1 and another other standards to promote digital control in external ac-dc power supplies. For example the UPAMD/P1823 is a standards working group sponsored by the Microprocessor Standard Committee (MSC) of the IEEE Computer Society. The project was authorized by the IEEE Standards Association Standards Board in June of 2010. Specifically, the Universal Power Adapter for Mobile Devices (UPAMD™) standard defines a power delivery connection between a power adapter and a power-using device in the 10 Watt to <240 Watt range.

A communications link between the power adapter and the mobile power-using device is also defined in this standard. The communications may be used to coordinate the power delivery and provide identification between the power adapter and the device. While intended for portable computing and entertainment devices, this standard may also be used with other mobile devices in offices, homes or vehicles.

The increased power level of USB 3.1, along with power being delivered to multiple devices, could drive the need for programmable control of battery chargers and adapters. With such functionality already being a “preferred” mode of control in certain dc-dc converter applications, it will eventually migrate into external ac-dc power supplies, as well.

Chip makers and power supply manufacturers now have the technology needed to undertake the transition from clunky black bricks and wall warts to sleek, efficient digital power adapter architectures capable of exchanging information between the power source and the load and adjusting power use according to product need.

Another area of interest is advancement in standby power management. It is generally accepted that the energy consumed by external chargers left plugged into an outlet while disconnected from the end product – accounts for a substantial portion of the energy consumed by mobile devices. The only means of eliminating this waste has been with a mechanical switch, a feature rarely found on mobile-device power supplies. To address this, a number of semiconductor companies have introduced products designed specifically to both lower costs and reduce standby power in consumer electronic devices.

Dialog Semiconductor offers a digital pulse width modulation (PWM) controller that was designed to efficiently drive low-cost, 10W power bipolar junction transistor (BJT) switches to reduce the BOM cost in 5V/2A smartphone adapters and chargers. The company’s iW1679 allows designers to replace field effect transistors (FETs) with lower cost BJTs and address the market trends for lower standby power and higher light-load and active average efficiency in smartphones, media tablets and consumer electronic products.

The use of the Dialogs iW1679 enables designers to meet or exceed the emerging global energy standards, including the stringent European CoC Version 5, which is anticipated to require 76% active average efficiency and high light-load efficiency down to 10% loads, as well as the proposed U.S. DOE regulation, expected to require 79% active average efficiency, and the Energy Star EPS 2.0, which will require 73% active average efficiency.

In addition, technology developed by Texas Instruments (TI) is also expected to contribute to the reduction in standby power. In March of 2014, Texas Instruments introduced two flyback power solutions that claim the highest energy efficiency and lowest standby power consumption for 5-100W ac-dc power supplies. The UCC28910 700V flyback switcher and UCC28630 high-power, green-mode controller with primary-side regulation (PSR) both achieve sub-30mW standby power and expand TI’s portfolio of flyback controllers covering a power range of ac-dc adapters and power supplies used in personal electronics, printers, white goods and smart meters.

Additional areas to watch are advances in technology, components and materials, in particular advanced semiconductor materials such as Gallium Nitride (GaN) which is expected to have an impact on the power supply market over the forecast period. The Adoption of GaN technology will have a major effect on the external power supply market over the next several years, as the technology promises both smaller and more efficient ac-dc power supplies and dc-dc converters.

According to GaN Systems, a Canadian manufacturer of power conversion semiconductors for cleantech applications, GaN devices offer five key qualities that make it unique: high dielectric strength, high operating temperature, high current density, high-speed switching and low on-resistance. These traits are due to the properties of GaN, which when compared to silicon, offer ten times higher electrical breakdown characteristics, three times the bandgap, and exceptional carrier mobility.

However, the current challenge faced by GaN technology remains cost, as an expensive and extensive process is required to grow a GaN crystal or wafer on which transistors and integrated circuits (ICs) can be fabricated. A number of companies are exploring the use of GaN technology in a variety of areas and once the process is implemented on a large enough scale, the cost should eventually come down.

The adoption of GaN technology is expected to have an effect on the external power supply market over the next several years. The California-based startup Transphorm has developed power electronics technology based on gallium nitride, a semiconductor that wastes far less power than the silicon components used in conventional devices. Not only are these electronics more efficient, they can also do without some of the bulky cooling systems.

For example, the company hopes to reduce the size of the charger bricks required by laptops today—or eliminate them altogether by incorporating the necessary electronics into the computer itself. The more compact design is also important for automobile applications, where space is limited and weight is important to fuel efficiency. Transphorm believes it can reduce wasted electricity by 90%.

A startup called FINsix has developed laptop power adapters that are 75% smaller than their conventional counterparts. The technology employed could also be used to improve the efficiency of a wide variety of devices and appliances, including washing machines and air conditioners.

The FINSix adapter is GaN-based and is currently expensive at $79.00 per unit (Retail for a PC) which is about 7 or 8 times as expensive as a common notebook power supply. However, if they can they bring down the cost into the same $/W as today’s designs it will have a transformative effect on the ac-dc adapter industry. The 65W power adapter operates at 30-100MHz and can be used to charge a variety of laptops or other devices such as smartphone or tablets (it comes with a 2.1A USB connector)—it can even charge more than one device at a time.

FINsix’s power adapter is called the Dart and is an after-market charger that can work with a variety of laptops and other devices. This GaN-based device shrinks power electronics by increasing the frequency at which these devices operate. The higher the frequency, the smaller the device can be. Ordinarily, higher frequencies also reduce efficiency.

However, researchers at MIT and FINsix developed a way to recycle much of the energy that’s normally lost inside a power adapter, improving efficiency and making it practical to use frequencies 1,000 times higher than those used in conventional power adapters. Production of the North American Dart (US prongs) will begin in the fall of 2014.

Due to the sheer size of the overall external ac-dc power supply market it is an attractive opportunity for digital power supply manufacturers and is projected to see considerable advancement over the next several years.


About the Author

Richard Ruiz is a Research Analyst at Darnell Group. Mr. Ruiz is a regular contributor to Darnell in Depth, EDN Power Technology Magazine, Bodos Power Systems and several other publications


This article originally appeared in the Bodo’s Power Systems magazine.