Hello,
I am a new beginner with PoE (Power over Ethernet). I'm working with the TPS 23750 on the evaluation board HPA 107.
HPA 107 documentation : http://www.ti.com/lit/ug/slvu136a/slvu136a.pdf
TPS 23750 documentation : http://www.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=slvs590b&fileType=pdf
On this evaluation board I have an output voltage of 5v. I'd like to modify the board to get 12v.
Apparently I have to modify 2 resistor R6 et R10.
For R6 I have to calculate its value to get 1.5V between SEN and SENSP (I found R6 = 10449 ohms)
But for R10 I don't know how to calculate its new value. Apparently the voltage on R10 should not exceed 0.5V. To calculate R10 I need to know how much current is going through it. But how can I calculate this current (in particular the peak current) ?
If you have an idea thank you ;)
Please see the PMP4679 reference design http://www.ti.com/tool/pmp4679 which is available on the TPS23750 product page. C9-C12 values will change as will L2. The current through R10 produces a voltage proportional to the FET and inductor switching current. You can view this EVM design as a positive side buck converter and use traditional buck converter design guidelines.
Thank you for the answer.
I'll try the PMP4679 reference design