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18W Led Driver using LYT7504

Posted by: nilsao on Tue, 08/20/2019

Hello everybody!
I am developing a driver for led lamp, using the following features:
Output: 72V/240mA (24s4P)

This driver will be placed in a 1.20 meter tubular lamp. An average of 90 light bulbs of this type will be used installed on the same power grid to illuminate a chicken house.
Attached, I send my circuit, which I have already done the prototype and in isolated tests at 220Volts, the circuit behaved well.

My question is: Do I need to be more careful with the input filters? Since more lamps will be turned on in the same primary loop
Can I use this type of inductor without GAP?
At this output power is the LYT7504 indicated? Or would it be better to change my output to a lower voltage and change my LED arrangement?
I want to produce in scale now, so I ask your help ...

Thank you very much in advance!


Attachment Size
Circuit.PNG 86.83 KB


Submitted by PI-Martok on Thu, 08/29/2019

Thanks for choosing Power Integrations LED driver IC. LYT7504 has been discontinued and we do not recommend using it for new design especially for high volume build. But if you would like to used it for few samples only, Here are my recommendations upon reviewing your LED driver requirement.

1. The LED driver circuit that you attached is for triac dimmable application which means that the input filtering(L1, R2 and C3) and fuseable resistor(R1) are lossy to prevent light flicker and shimmer during phase cut tric dimming. If your application is for non triac dimming then you can removed R2 and C3 and use Fuse For R1 for better efficiency. Also you can try to lower the inductance of L1 to reduce copper loss.

2. For the buck inductor, It is oK to use dog bone type inductor like what you've shown on the attached circuit diagram. You just need to ensure the DC current rating is enough for 240mA output current to avoid core saturation. The bigger the better.

If your product is for high volume quantity, I recommend using an active product which is LYT5228D LED driver. You can refer on below link for design example(DER-526).

Best Regards