Solution Finder

110VDC input power supply for T8

Posted by: Wilsonhan on Wed, 07/18/2012

Dear Sir,


I am wondering if you could have  products for 110vdc input power supply for LED T8.

Its input range: 77 - 138 VDC.




Submitted by PI-Skywalker on Thu, 07/19/2012

Most of PI products can be used for 110 VDC input power supply for driving LED T8.

What is the output voltage and current of this LED driver?

Submitted by Wilsonhan on Thu, 07/19/2012

Thanks PI-Skywalker,


Output voltage:36 or 42V

Output Current :430mA


I am wondering if PI's products could work between the range 77 - 137.5H VDC.






DER 257 is univesal input 12 W buck converter design using LNK405, and you might be able to increase the output power using larger device. For T8 LED application you might need to use a couple of SMD power inductors in series.

Submitted by Wilsonhan on Fri, 07/20/2012

Thanks PI-Skywalker,


I have one more concern about its input range.


In DER 257, it says that its min input voltage is 90 VAC and Max input voltage is 265VAC.

After rectifier bridge, Min 90VAC is converted to 136 VDC(1.4X90).

I am wondering if its constant current could wok  well in the input voltage range of 77VDC to 137.5VDC.


I really appreciate for your help.


Best Regards

Submitted by PI-Skywalker on Fri, 07/20/2012

The Vpin resistors in RD254, R3 and R4, need to be changed to lower input undervoltage limit for 77 VDC input.

When I lowered R3 to 1M ohms, R7 to 50 K ohms, and added 150 uF in parallel with C1, the output current was 0.58 A at 32 V output. The input was 60 VAC, and the measured voltage cross C1 was 74V DC.

Thanks PI-Skywalker,


Your solution is very helpful.