Need help selecting a LED driver

Hello,
A little more information may be useful. Does this have to be isolated or not? What power factor are you looking to achieve? Would the 45 volt solution need to be Class 2? Does it have to dim? If so 0-10 or other dimming method?
It appears you may be developing a ballast type solution with the lamps separate from the power source? If so how do you plan on balancing the LED loads? We do have solutions that can balance current between strings if that is what you are looking for.
Thanks,Irwin

Hi Irwin,

We would like these to be class 1. So an isolated supply would be necessary. Low cost is the main consideration.

Dimming is not required.

PF > .90

Line input range 90- 305VAC.

The 36V model is for a high bay lamp. Output load current is 1.5A

The 45V model will come in 2 versions. 45V at 750ma. and 1.5A. The lower current design is for a 2 lamp T8 design, the higher current is for a 4 lamp design.

This design will be for a luminare.

All of these designs will be in a ballast type housing.

Any help pointing us to a specific part or reference design would be appreciated.

Thanks,

Hello,

I forgot to ask, we would be interested in the load balancing would be done for the 2 and 4 T8 lamp designs.

Thanks

Hello,

There are quite a few ways of approaching this.  I would probably go the route of creating a flyback voltage regulator using the UCC28810/11 at around 52 volts or so.  If it can be kept below 100 watts and 60 volts you can go for class 2.  Then I would use something like the LM3409 as a buck converter to regulate individual strings.  This solves the load balancing issue.  The benefit of this is you have high bandwidth at the last stage so changes in input voltage tend to not show up in the light level.  Another benefit is if you regulate voltage you can change the load, two lamps versus four lamps without having to change the first stage (isolation stage).  This also has the benefit of regulating current at each string so if one opens the remains strings current does not change.  If it is class 2 the LM3409 circuits could be on the lamps instead of part of the ballast.

Another option is to use the UCC28810/11 as a current regulator and provide load balancing with the LM3466.  This would require two different current settings between the two and four lamp solution.  A possible issue is a fault in one LED load will cause the current to go up in the remaining load(s).  Routing the output of the LM3466 could be interesting depending on how the system is constructed.

If you just want to send current to two or four strings that can be done as well.  There are disadvantages to this such as the low PFC bandwidth will allow input line changes to show up in the light level.  There is also the issue of load balancing (due to heating or differences in LED Vf) and fault protection if an LED sting opens or an LED shorts (so the stack voltages are different).  A discrete circuit could be used to balance the LED loads with a slight efficiency drop.

Thanks

See other reply,

Can be done with independent buck converters, LM3466 or even a discrete circuit.

Hi Irwin,

Thanks, will look at all of this.

Paul