LNK306 and 42VAC. Is it possible?

Posted by: Yaumen on 12/13/2013

Hi,

At the moment we're using LNK306 for the LED lights with 230 VAC input. Output voltage is 24 VDC (0,3 - 0,36 A).

Will it be able to work with 42 VAC input?

If not, perhaps you could prompt another device for this task. It would be great if it will be pin-to-pin compatible with LNK306.

Best regards

Comments

Probably not, But to make sure can you please tell me more about your design?

Is the design a buck or flyback ? What is your minimum input voltage requirements?

Thank you.

Here some information about our design.

Our design is a signal head for traffic lights. Now it works for 230 VAC application. But our clients ask to us to redesign their to 42 VAC +/- 20%.
Signal head's power is less then 6,5W.
All our signal heads are working with LNK306 in the non-isolated buck mode. We tried to use TOP family (TOP222 and TOP252) but they have too long start-up time for the traffic lights applications.

I can check if you tell me if you need a buck or flyback topology

do you need VOUT to be isolated from the input?

For our design is quite enough non-isolated buck topology. Vout don't isolated from the input

It does not work. for a buck converter you have only about 10 volts from input to output.

It is not enought for the controller to run

Why about 10 volts? Input voltage is 42 VAC. It's equal about 58 VDC on the input of LNK306. Output voltage is 24 VDC. It's a difference more then 30 volts.

I am sorry for the wrong answer.

You need 50 V from DRAIN to SOURCE for the controller to be able to run. With 42Vin (59VP) minues 24VOUT, you have 35 volts from DRAIN to SOURCE. you have to take in account for the ripple voltave in the input cap . So your design is not guaranted to work with such input voltage.