• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 712 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: C1 and C2 Calculation Double Check

Eric Scott70
Intellectual 370 points
Part Number: BQ51013B

Hello All,

I am currently trying to diagnose issues that I am having with a BQ51013B during power transfer. I am not getting a regular 5V output on the OUT line, instead it is floating around 1.5V while on the TX coil. When I watch the RX and TX coils during startup, the control loops appears to fail to lock in on a resonant frequency for power transfer. I measured the "Ls" and "L's" coil inductance as detailed in the BQ51013B datasheet (11.814 uH, 11.027 uH respectively). When I ran the numbers I found that we should have C1 and C2 values of 214.4 nF and 2.322 nF. In our system, C1 is currently 183 nF and C2 is 1.9nF. Is that difference between the ideal and implemented C1 and C2 values enough to throw off my wireless charging system?

Best regards,

Eric

  • 0
    TI__Guru* 75656 points

    Hi Eric

    The C1 and C2 value of is close enough.  It is best to measure L's with the coil in case with all the final parts around it.

    Take a look at FAQ section -- in the TX Trouble Shooting Guide -- Slide 6 will show a normal RX start up.  Take a look at that one and see how it compares to your unit. 

    Very good point to look at on the RX is Vrect, it will tell you a lot about the start up and regulation behavior.