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TPS92511: Best part for a 48V, 350mA LED

Part Number: TPS92511
Other Parts Discussed in Thread: LM3414HV, TPS92551

Hello.

I need to control some 48V, 350mA LED arrays with PWM signals. Previously I have made tests with the LM3414HV driver, but now I see that there are other possibilities, namely the TPS92511.

In the spec sheets of the TPS92511, I have seen that the configuration is practically the same as the LM3414HV, just changing some values of the components. I also read that it is feasible to design a single layer circuit, but couldn´t find the conditions in wich this is possible. This characteristic would be great to simplify the design and manufacturability.

Could you please give me some assistance to choose an adecuate solution? Wich of these parts is the best? Or is there another solution that is better?

Also, I think it is important to notice that the lamps may work 24/7, depending on some lighting scenarios present in the project.

Thank you very much.

  • Hello Luis,

    The TPS92511 is a good choice for that current level. It also has few components so a single layer board is relatively easy to make for this design. The only thing to make sure of is that VIN, LX, and LED- are all tied closely together to minimize the switching loop.

    An even easier option that really makes a single layer layout much more simple is the TPS92551. It is fully integrated and very easy to use. Both are very reliable long term.

    Regards,

    Clint

  • Thank you very much for your response, it has helped a lot.

    I have analysed the TPS92551 and it also propose to do the thermal dissipation with a two layer PCB. Will the circuit have the same reliability in a single layer board? Does the cupper dissipator needs to be adjusted with respect to the one proposed in the datasheet?

    Once again thank you very much.

  • Hello Luis,

    A single layer board should be fine. Just make sure you have a good top layer ground plane to dissipate the heat. The recommendation would be for a worst case thermal situation which is the maximum input voltage (AC losses are proportional to Vin^2) and maximum output current (switch loss proportional to I^2). So you are not running the maximum of either so it will run cooler. It should be easy enough to keep the maximum junction temperature below 125C even with a single layer.

    Regards,

    Clint