Dr. Michael Heidinger
CEO, Digital Power Systems - based on his PhD thesis at KIT
CEO, Digital Power Systems - based on his PhD thesis at KIT
Why Do LED Luminaires Fail?
A study by the US Government's Building Technology Office shows that 52% of all LED streetlight failures are related to the power supply - and only 10% to the LEDs themselves. A truly long-life power supply is therefore critical for overall luminaire reliability.
The Lifetime of LEDs
An optimistic estimate for LEDs is 150,000 to 200,000 hours of lifetime at 65 °C operating temperature. This equals approximately 23 years of continuous operation. For commercial applications, LEDs may therefore be replaced due to technical innovation rather than due to defects.
💡 Core problem: In contrast to LED lifetime, the driver service life ranges between just 20,000 and 50,000 hours. This means a power supply has to be exchanged four to ten times before the LED module reaches its end of life. Therefore, the LED driver is typically constructed to be replaceable - not the LED module.
What Limits the Lifetime of LED Luminaires?
Based on our experience, lifetime is limited by the following factors:
- Fans: Susceptible to dust, clogging air channels. Typical maintenance interval: 7,500 to 15,000 hours. The good news: most LED drivers do not require a fan.
- Electrolytic capacitors: Typical high-temperature lifetime (70 °C) of 30,000 to 50,000 hours. With adequate design using film capacitors, 200,000 hours are achievable.
- MOSFETs and switches: Can be destroyed by overvoltage. Stress parameters must be measured under high-line operating conditions.
- Overvoltage protection: Particularly critical in LED street lighting - adequate protection is mandatory.
⚠ Industry reality: Typical high-volume manufacturers often will not admit that their technology has natural limits. Internally, they hope to outlast the warranty period. This may work for disposable products - but not for long-lasting industrial equipment where your brand is at stake.
Where to Get Long-Life Power Supplies?
We should take a step back from our disposable culture and invest in high-end, long-life equipment. One approach I am an evangelist for: construct long-life power supplies. If the power supply breaks, everything else breaks too.