• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 16 subscribers
  • Views 2010 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

EZ430-TMS37157: Need help with hardware design

Gerd Christian Knese13
Intellectual 410 points
Part Number: EZ430-TMS37157
Other Parts Discussed in Thread: MSP430F2274, TMS37157, LM2767

Hi,

I recently bought the EZ430-TMS37157. My idea was, to switch of the on-board MSP430F2274 via software (all GPIO to input, WDT off, LPM4) und use the TMS37157 with an external circuit.

A part of my external circuit needs 12V (just a few milliamps), so I throught it's a good idea to use two LM2767 voltage doubler in a series to do that.

The first one does a perfect job. I got a little more that 6V.

But when I add the second LM2767, the whole VCC chain brakes down. All signal shows just 3V ripples.

Any idea why?

Kind regards

Gerd

  • 0
    TI__Guru*** 135355 points

    Hello Gerd,

    Are you have a power problem relating to the LM2767? If so, I can direct your post to the right forum to help with that.

  • 0 in reply to Ralph Jacobi
    Intellectual 410 points

    Hi Ralph,

    > Are you have a power problem relating to the LM2767? If so, I can direct your post to the right forum to help with that.

    I'm not sure, if it's a problem with strange behaviour of the TMS37157 or the LM2767.

    Because the TMS37157 is the more complex IC, I thought it's a good starting point to identify the problem.

    Kind regards

    Gerd Knese

  • 0 in reply to Gerd Christian Knese13
    Intellectual 410 points

    Hi Ralph,

    In the meantime I solved this problem myself.

    I killed the second LM2767 because the input voltage was too high (6.6V).

    By solving this problem, I found the next one. VBAT is not able to deliver enough current to my circuit.

    So, I tried to reproduce the circuit from SWRA395 with my EZ430-TMS37157, a schottky diode 1N5819 and a LM2936-3.3,
    to feed into my voltage doublers LM2767.

    I connected the schottky diode 1N5819 on top of the EZ430-TMS37157 PCB on test pin VCL and the LM2936-3.3 and a 10uF behind,
    but with this (voltage doubler disconnected), the whole RF power brakes down (below 2V) and the TMS37157 becomes unreadable.

    Can you please help with this?

    By-the-way, do you know the link to download the Windows GUI from SWRA395?

    I may need the expert mode for test. I hope a longer charging time will solve my problem.

    At the moment, I'm using the PaLFI demo GUI with SPI Access.


    Kind regards
    Gerd

  • 0 in reply to Gerd Christian Knese13
    TI__Guru*** 135355 points
    Hello Gerd,

    You will get maximum 16mA from VBAT, so that is probably the issue. If you need more than that, then you will need to find another source.

    I couldn't find any released GUI's with expert mode, but I don't think that will solve your hardware problem.
  • 0 in reply to Ralph Jacobi
    Intellectual 410 points

    Hi Ralph,

    Thanks again for your help with this.

    > I couldn't find any released GUI's with expert mode, but I don't think that will solve your hardware problem.

    Sorry to disagree, but it looks to me (on my scope), that the RI-ACC-ADR2-10 is not charging my modified TMS37157 target board long enough to harvest enough energy to fully charge my capacitors.

    Do you have any documentation about the USB interface telegram for the RI-ACC-ADR2-10?

    I found this document "11-07-21-024 RFID Demo Software Users Guide for AES and 80 bit Product Family Rev1.pdf" and on page 9 is a picture of an other GUI (WW MCU-Automotive RFID Demo Software) and it says on page 67 "The related USB / serial protocols are described in the document Car Access Demo Protocol Description." But, I could find this document or the other GUI.

    Having this in hands, I'd be able to write my own GUI with extended charging time or just use a terminal software for some tests, to see if this could work.

    The source code of that was written by Juergen Austen in 2008. You may ask him?

    Kind regards

    Gerd

  • 0 in reply to Gerd Christian Knese13
    TI__Guru*** 135355 points
    Hello Gerd,

    We cannot provide source code for the GUI. I don't know of any documentation for the USB interface, but I can ask along with asking about the GUI which has 'expert mode' tab.
  • 0 in reply to Ralph Jacobi
    TI__Guru*** 135355 points
    Hello Gerd,

    Actually, belay the questioning about expert mode... I stumbled onto the answer that was right in front of my face the whole time.

    The Demo GUI shown in SWRA395 has a new version which you can download here: www.ti.com/.../swrc164

    In this version, the 'expert mode' tab is titled: Direct Access Mode!! :)