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TPS9210EVM-592: Performance Problem

Julio Cuevas
Prodigy 20 points

Hi,

I recently bought the evaluation board TPS92010EVM-592 and it works fine, so I tried to build my own bord using a circuit that  you have in the users guide but for some reason it didn't work, the document  is "sluu418c.pdf", I downloaded from this link http://www.ti.com/litv/pdf/sluu418c,  I bought all components that the document asks for, except the mosfet because I coundn't get it because of delivery times, so I replaced it with STD3NK80ZT4, which is the only diference between the two boards but in the board I made the maximun voltaje that I get is 12.7V with a 100mA load and 17.3V without load, I tested all configurations of constant current that the document says but the problem still continues, I got little variations between the differents configurations but nothing relevant. Also the efficience is bad, it is arround 62%.

Can any one make me some recomendations about it? or Does anybody know how to solve this? I will appreciate any suggestion.

 

JC

  • 0
    TI__Genius 15910 points

    Hi Julio,

    Did you use the same PCB gerber files that were used for the HPA592?  The regulation issue may be layout related (perhaps the controller is missing the valley due to noise).  I would be happy to forward the gerbers to you if you dont already have them.

    The MOSFET that you selected has higher Rds(on), longer rise and fall times, higher gate capacitance, and higher total gate charge which will all add up to greater losses.  I'm not completely convinced that they add up to a 22% difference in efficiency but as the MOSFET, the transformer, and the output rectifier make up the majority of the losses and this is a low power design, I would expect lower efficiency when using the ST FET. 

  • 0 in reply to Lisa Dinwoodie
    Prodigy 20 points

     


    Hi Lisa,


    Sorry for the late, I had no acces to computer

    yes please, can you send me the PCB gerber files? and Can you make me some recomendation to replace the MOSFET? because I can't get this part number,the dealers  hasn't this part number in stock  (Digikey, Mouser, Newark ). 

     

    JC