Power Over Ethernet

Reference design for TPS23754 3.3V output

SanchoPancho — Tue, 17 Nov 2009 09:55:50 GMT

Hi,

Is there a reference design for TPS23754 for 3.3V output? There is only reference designs for 5V and 12V outputs.

tnx

IEEE 802.3af standard problem using the TPS23750PWP

Jelle — Fri, 25 Sep 2009 15:19:56 GMT

Hello,

I have a problem with my currently designed PD device. I used at this moment the spare lines for getting power for my pd device. The problem is that a Endpoint (end-span) switch needs to see the pd on the spare-lines and data-lines. To make our system accept power from the datalines isn't possible because the transformer isn't suitable for POE current.

The only way to let the switch believe that there is a correct PD device present, is to place a 25k Ohm resistor between the transformer points of the data lines. But is this possible and does this work or is this allowed??

Hopefully you can answer my question.

Thanks,

Jelle

Output Voltage Range of PoE controllers with built-in DC/DC converters

Johnny T — Wed, 10 Jun 2009 08:11:28 GMT

Hi.

I'm normally not designing power-related circuitry, but now I'm considering the using the TPS23754 in a design. I have tried to read the spec, but I'm still not sure about the output levels and how it's adjusted.

I need to generate a +24V system voltage (1A max current), from the ethernet cable. Is this voltage level achievable, and what transformer should I use?

I'm planning on implementing this feature on a Gigabit LAN. Do you seee any problems with that?

doubt related to my project

nikunj shah — Tue, 24 Feb 2009 14:02:12 GMT

Introduction:
Hello sir, myself Nikunj, trying to make project on “ETHERNET ENABLED UNIVERSAL CONTROLLER" it means that it would be monitoring (sensing) and controlling various parameters at a time and also on a single cable. In my project I’ve taken thermocouple, PT-100 RTD, 1-5 volt signal source and 4-20 mA current signal source and would be providing these all signal conditioning to convert them into 1-5V signal. Then I would be multiplexing and converting them to digital signal by ADC with inbuilt MUX and transmitting data to microcontroller which I would be programming to display data on local LCD and also on a PC for a front end purpose. I would be providing 6push buttons to make different settings such as 'enter, up, down, shift left, shift right, auto- manual mode purpose'. I’ll be implementing software temperature compensation for thermocouple and RTD in program itself. I'll be implementing PID algorithm for controlling purpose of parameters at their set point and outputting these data on DAC to D_MUX to 4 different controlling elements such as valves. I've also provided ETHERNET IC interfacing with microcontroller.

PROBLEM:
Now the problem I'm facing is the selection of components, especially microcontroller because ADC which I’ve selected has serial output and DAC has serial input, PC also has communication via serial port. If I think, Ethernet IC would also be having serial communication. How would I interface all these components on microcontroller having one serial port? Also I need to interface LCD and switches beyond that. So if u please suggest me any microcontroller for this purpose that would be able to interface all these devices and if u suggest name of each components from TI and circuit diagram of the whole interfacing, it would be very thank full to you. I was wishing to select TLK1201ARCP ETHERNET IC and ADS1256 ADC with inbuilt MUX from TI.
REQUEST:
right now I'm having exams which will be over by the end of January. So if u provide me the whole circuit so that I can give it for fabrication by this time and after that I can focus on programming it would be very thank full to you.

Yours sincerely,
NIKUNJ SHAH