Long lifetime is cited as a key advantage of LED-based systems, but long-term reliability is determined not only by the LEDs themselves but also by the electronic components that provide power to the light sources.
With this in mind, NXP has been carrying out continuous testing of LED driver ICs since December 2008, and has reached 7,000 hours with zero failures from the batch of about 70 samples. The tests of NXP’s SSL2101 integrated dimmable mains LED driver IC were carried out under high-stress conditions, with an IC junction temperature of 150°C.
The test goes well beyond traditional lifetime testing procedures in the semiconductor industry, which are typically based on 1000 hours of testing time. After this time, assuming no device has failed, the test is successful.
NXP claims that its results demonstrate that its mains LED controller and driver ICs are capable of matching LED lifetimes. Testing for 7,000 hours at 150°C is extrapolated to over 35,000 hours lifetime at 115°C and over 60,000 hours lifetime at 105°C.
While the LED industry is still trying to agree extrapolation methods for light sources, driver ICs can make use of procedures developed over many years of experience in the mainstream semiconductor industry.
Multiple tests and set-ups were used to detect all possible failure modes in several use cases: continuous-on, on/off switching cycle and various combinations. NXP plans to assess the actual lifetime of its latest LED drivers, running reliability tests until product end of life.
“LED lighting has the potential to be ten times more efficient than incandescent lamps, with manufacturers reporting lifetime figures exceeding 50,000 hours. The reliability of the electronic components – particularly the LED driver – is critical to the overall reliability of most LED systems,” said Jacques le Berre, director of marketing and business development for lighting solutions, NXP Semiconductors.
“Through our ongoing lifetime test…we’ve set a new benchmark and proven that NXP’s mains LED controller and driver ICs are up to the challenge of supporting extreme long-life lamps.”
Le Berre told LEDs Magazine that NXP has many years' experience in AC to DC conversion, which is a requirement for (DC-driven) LEDs connected to the (AC) mains. The focus for NXP's LED drivers is to make them very power-efficient with small form-factor. NXP also has more than 20 years' experience in providing power to traditional (non-LED) light sources.
NXP has also introduced the SSL 2102 integrated dimmable mains LED driver IC for SSL retrofit lamps and modules (see press release), as well as launching its online design tool for SSL applications, which makes it easy for engineers to test the behavior of LED lighting applications based on four NXP products.
