• State Resolved
  • Locked Locked
  • Replies 9 replies
  • Subscribers 63 subscribers
  • Views 1734 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.

BQ51013B: Device not starting up

Matthew Kozak69
Prodigy 55 points
Part Number: BQ51013B

I've tried many C(coil)1, C(coil)2 combinations with several coils of different sizes and inductance and I am unable to get voltage outputted from the device.

I'm using my own custom board, and I tried it on four different boards; however, the problem still persists despite using various inductors and capacitors, with two different transmitters. I used Figure 48 on the product's datasheet as reference for my design.

I captured Vrect for review.

The RECT cutoff timing changes depending on the capacitor values chosen. I used the calculations as a base, and then I change out C(coil)1 and C(coil)2 in an attempt to tune it but I still haven't been able to get it working yet. Do I just need to keep trying different capacitors to tune it until it works, or do I have a different issue?

How should I go about troubleshooting this problem? Thank you for your assistance!

  • 0
    TI__Guru* 75486 points

    Hello

    The schematic look OK.

    1.) R-ILIM R13 / R14 is a little low may need to increase, but do not think that is the problem

    2.) R-OS R6/R7 for now remove, value needs to be set later.

    The scope capture looks odd.  The jump in voltage may be the output turning off and rectified voltage jumping up.  Problem would not be the jump but why output turns off.

    Could you check the output vs RECT?

    Also typical RECT start up waveform attached.4062.bqTESLA FAQ--Start up.pdf

  • 0 in reply to Bill Johns
    Prodigy 55 points

    Hi Bill,

    Thank you for your feedback! I increased R13 and R14 to a total of 113Ω, combined with Rfod at 196Ω gives a total Rilim of 309Ω.

    Also, I temporarily removed R6 and R7.

    I think the oscilloscope reading only looks different due to the locations of the coils. Vrect (blue) still doesn't look like the Start Up example that you provided. Vout (pink) never seems to become active. Is there anything else I should try?

    Thank you so much for your help!

  • 0 in reply to Matthew Kozak69
    TI__Guru* 75486 points

    Thanks for the additional data.

    Unfortunately it does not help -- Vout does not move.  

    What is your output load, could you test with a resistive load?

  • 0 in reply to Bill Johns
    Prodigy 55 points

    Hi Bill,

    The previous oscilloscope captures had no load on Vout.

    I used an LED with a 510Ω resistor as a load and captured the following oscilloscope reading:

    Here is what my coil V looks like. For all of these oscilloscope readings, I have C1(coil) = 183nF and C2(coil) = 2100pF with Ls = 12uH. I have tried many different combinations, but I can try a specific combination if you'd like me to get an oscilloscope reading of different values for comparison.

    Some inductors that I have readily available include: 12uH, 13.9uH, 14.3uH, 16.7uH, 25uH, and 47uH.

    Thank you again for your help!

  • 0 in reply to Matthew Kozak69
    TI__Guru* 75486 points

    Hello

    This does not look like an inductor or tuning problem.

    The RECT has a sharp jump then goes flat.  We can see the RX is sending Control Error Packets (CEP) when the voltage is lower and voltage is moving.  It could be the TX changing operating point very quickly then comm is failing.

    What TX are you using do you have another one?

  • 0 in reply to Bill Johns
    Prodigy 55 points

    Hi Bill,

    The problem occurs using a transmitter from TDK (WTM505090-10K2-5V-G1) and an off-the-shelf charger from Amazon.

    We also bought a receiver from Adafruit (1901), which uses the BQ51013B, and this product works fine with both transmitters.

    Thank you for your help!

  • 0 in reply to Matthew Kozak69
    TI__Guru* 75486 points

    Thanks for the additional info.

    The TX look OK, Qi certified.  There are chargers on the market that are Qi compatible, this is un-defined and has some risk.

    Jump in the RECT waveform does not look right but not clear what is causing this. 

  • 0 in reply to Bill Johns
    TI__Guru* 75486 points

    Hello

    I would like to work with you offline on this problem and have sent you a request.

    We have covered all the obvious problems and need to go into a trouble shooting mode.

  • 0 in reply to Bill Johns
    Prodigy 55 points

    I got it working. One of my two boards had a manufacturing defect on one of the traces and that was the primary board that I was working with. Thank you for your patience and guidance!