By Jeff Schnabel, Vice-President of Global Marketing, CUI Inc.
The global regulatory environment surrounding the legislation of external power supply efficiency and no-load power draw has rapidly evolved over the past decade since the California Energy Commission (CEC) implemented the first mandatory standard in 2004. With the publication of a new set of requirements by the US Department of Energy (DoE) set to go into effect in February 2016, the landscape is set to change again as regulators try to further reduce the amount of energy consumed by external power adapters.
Mandating higher average efficiencies in external power supplies has undoubtedly had a real impact on global power consumption. However, with the benefit of a reduced draw on the power grid come challenges and uncertainties for the electronics industry as it tries to keep up with this dynamic regulatory environment.
OEMs which design external power supplies into their products must continue to monitor the latest regulations to ensure that they are in compliance in each region where their product is sold. While the new standards enacted by the DoE will only be mandatory in the US, any OEM wanting to supply products in the US should be taking action now to ensure that they comply.
The evolution of efficiency regulation
In the early 1990s, it was estimated that there were more than one billion external power supplies in use in the US alone. The efficiency of these power supplies, which mainly used linear technology, could be as low as 50%, and they still drew power when the application was turned off or not even connected to the power supply, commonly known as the ‘no-load’ condition. Experts calculated that without efforts to increase efficiency and reduce no-load power consumption, external power supplies would account for around 30% of total energy consumption in less than 20 years.
As early as 1992, the US Environmental Protection Agency started a voluntary programme to promote energy efficiency and reduce pollution; it eventually became the Energy Star programme. It was not until 2004, however, that the first mandatory regulation governing efficiency and no-load power was put in place, and there has been constant change since then, as shown in Figure 1.
Today, the US and Canada mandate Level IV efficiency, while Europe sets a higher Level V standard. From February 2016, however, the US DoE will require compliance with the more stringent Level VI standard. Power supply manufacturers indicate compliance by placing a Roman numeral on the power supply label as specified by the International Efficiency Marking Protocol for External Power Supplies version 3.0, updated in September 2013. This latest version of the Protocol provides additional flexibility on where the marking may be placed, as shown in Figure 2.
While the European Union is, as of October 2015, the only governing body to enforce compliance to the Level V standard, most external power supply manufacturers have adjusted their global product portfolios to meet these requirements. This is in response to the needs of OEMs to have a universal power-supply platform for products that are shipped globally.
The requirement for Level VI compliance in the US from 2016 is likely to induce power-supply manufacturers to adjust their product portfolios again, so that they can market Level VI-compliant products globally. How are the specifications of these new products different from today’s Level V power supplies?
New performance thresholds
The table below shows a summary of how the efficiency thresholds for external power supplies have become more stringent over time; a summary of past and current performance thresholds. The term ‘power’ means the power specified on the label of the power supply
The internationally approved test method for measuring efficiency has been published by standards body the International Electrotechnical Commission (IEC) as AS/NZS 4665 Part 1 and Part 2. The tester is required to measure the input and output power at four defined points: 25%, 50%, 75% and 100% of rated power output. Data for all four points are separately reported. An arithmetic average active efficiency across all four points is also calculated.
Some types of external power supplies are exempted from the scope of the standards in both the US and the EU, such as those for some medical devices, for battery chargers, and replacement parts for products first manufactured before 1 July 2008. A low-voltage external power supply, a unit with a nameplate output voltage of less than 6V and a nameplate output current greater than or equal to 550mA, will also be exempt.
The migration to Level VI efficiency
Power-supply manufacturers such as CUI are already prepared for the coming transition to the more stringent Level VI standards. This has not only called for design modifications to meet tightened regulations for existing adapters: the new standard also expands the range of products within the scope of the standard. Regulated products will now include:
The new performance thresholds are summarised in the tables below:
The new standard also defines power supplies as being either for direct or indirect operation. A direct-operation product is an external power supply which functions in its end-product without the assistance of a battery. An indirect-operation power supply is not a battery charger, but cannot operate the end-product without the assistance of a battery. The new standard only applies to direct-operation external power supplies. Indirect-operation models will still be governed by the limits defined by EISA2007.
It is expected that other nations will soon follow the US’ lead and implement Level VI efficiency standards. In the EU, the mandatory European Ecodesign Directive for external power supplies is currently under revision; it is expected to harmonise with most, if not all, of the US standards. It should be expected that countries with existing efficiency regulations in-line with those of the US, including Canada and Australia, will also move to harmonise with the new standard.
The EPA estimates that external power-supply efficiency regulations implemented over the past decade have saved some $2.5bn annually and reduced CO2 emissions by more than 24 million tons per year. Moving beyond the mandated government regulations, many OEMs are now starting to demand greener power supplies as a way to differentiate their end-products, driving efficiency continually higher and even pushing the implementation of control technologies which in some cases eliminate no-load power consumption altogether.
In late 2014, CUI began introducing Level VI-compliant adapters to keep their customers one step ahead of the coming legislation. In future, CUI will continue to look for ways to implement the latest energy-saving technologies into its external power supplies in order to address market demands and to comply with current and future regulations.
Details on all of CUI’s Level VI-compliant power supplies may be found here.