T
treez
Guest
![Newbie level 1](/styles/images/ranks/alevel1.gif)
Hello,
We have designed a 60W PFC’d Flyback LED driver. Output is for 60V LED string.
VAC input is 240VAC.
The output diode is STTH3010D.
When the LED driver is in its plastic enclosure, which is itself inside a metal enclosure, we record 120 degrees on the tab of the diode. This is with the equipment in 22 degrees centigrade ambient. We cannot afford to buy a bigger heatsink than the one that we have for it. And in any case, we couldn’t afford to re-do the board so we could fit a bigger heatsink in. –This is because the extra cost would make our product uncompetitive with already existing offthe shelf products made by huge electronics corporations.
The diode datasheet says it is for use up to 170degrees Centigrade at the junction. However, going above 100 degrees Centigrade obviously bares with it the danger of thermal expansion/contraction damage. However, our equipment is only switched on and off once per day.
Due to this, do you think that the product will not suffer badly from expansion/contraction damage, due to the low amount of power cycling events? (the product will be on full power for 6 hours per day)
The external ambient that the product is installed in has temperatures ranging from -10degC to 24degC.
STTH3010D datasheet:
https://www.st.com/resource/en/datasheet/stth3010.pdf
We have designed a 60W PFC’d Flyback LED driver. Output is for 60V LED string.
VAC input is 240VAC.
The output diode is STTH3010D.
When the LED driver is in its plastic enclosure, which is itself inside a metal enclosure, we record 120 degrees on the tab of the diode. This is with the equipment in 22 degrees centigrade ambient. We cannot afford to buy a bigger heatsink than the one that we have for it. And in any case, we couldn’t afford to re-do the board so we could fit a bigger heatsink in. –This is because the extra cost would make our product uncompetitive with already existing offthe shelf products made by huge electronics corporations.
The diode datasheet says it is for use up to 170degrees Centigrade at the junction. However, going above 100 degrees Centigrade obviously bares with it the danger of thermal expansion/contraction damage. However, our equipment is only switched on and off once per day.
Due to this, do you think that the product will not suffer badly from expansion/contraction damage, due to the low amount of power cycling events? (the product will be on full power for 6 hours per day)
The external ambient that the product is installed in has temperatures ranging from -10degC to 24degC.
STTH3010D datasheet:
https://www.st.com/resource/en/datasheet/stth3010.pdf