I have the bqTESLA kit, and it has started periodically failing to start up.
when i place the receiver on the tx pad (bq500110EVM-688), it struggles to start up.
Scoping the PWM output shows the pwm starting up, reducing frequency, then stopping
This repeats slightly quicker than once per second.
Sometimes this repeats for 20-40 seconds, then settles. Other times it never settles and continously repeats this.
Have tried different loads - doesnt seem to affect it. sometimes very slightly lifting the receiver up from the pad helps.
I have the earlier receiver bq25045evm-687 which never shows the same problem
Also, the red and green lights blink together - it is led mode 4, and the table doesn't mention both blinking together which is strange. Unless they are not actually blinking, but going from both on (standby) to a 'startup mode' then failing so going to standby?
Any ideas as what is wrong?
First place to look is the RX V-rect test point (TP12), what does the WF look like in no load condition. The voltage should converge on about 7V and hold steady.
Bill Johns, Applications Engineer
bqTESLA Wireless Power Products
Texas Instruments Inc
when first placing on Vrect rises up to around to around 5.8V (with brief pulses up to 8-10V) then cuts out, repeating this with the PWM coming on and off as described earlier.
When it eventually works Vrect converges at 7V.
I will contact you using the conversation feature of the forum regarding replacement of the unit.
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