BQ51050B: bq51050B (bq5105xB) Charging phase not start

zoom of pulses after first stage ends

Hi 

Try grounding the AD pin 

Pin may be floating up and setting wire charging and disabling wireless charging.

Hi Bill,

thank you. I grounded AD pin but no change. Receiver will start but after few seconds (2 maybe) it falls to pings again. Waveforms below are from receiver rectifier.

Hi 

Keep the AD pin grounded.

This could be End Power Transfer command, couple of things to check on:

1.) What battery simulator are you using?

2.) Can you take a scope capture of Comm 1 or 2 pin that shows the bit pattern.

3.) Do you have a 10k resistor connected to TS / CTRL pin?

Hi, thank you for hints, answers below:

1. User lipol battery precharged to 4V, then same battery discharged to 3V. Also tried regulated power supply with current limit to 500mA. All have same result.

2. Scope enclosed. first 2 images are for Ping , rest is message sent during init phase which end every time after 2 sec (3 different zooms of same view).

3. yes, 10k is present. There is 500mV pulse every 450ms on TS pin, otherwise there is 0V.

* Charger is Baseus BS-W510 just to report.

I think the packet is Signal Strength  ( 0X01) and is what is expected, first packet RX should send at start up.  NOT End Power Transfer.

Later one, last packet scope picture, is Control Error Packet which is normal also, sent every 250mS.

The problem could be communications, something to try would be increase comm1 and comm2 caps from 22nf to 44nf or 66nf.

I just tried 47nF and 69nF on COMM1 and COMM2 (both variants) with no difference. May I try another transmitter ?

Hi 

Problem still looks like a communications issue between the RX and TX.

A couple of things to try:

1.) Yes try another transmitter

2.) Coil tuning -- C107, 108, 109 are tuned along with coil Ls' to 100kHz.  With coil Ls value of 16.7uH my estimate of Ls' is 18uH.  That would put value of the three capacitors at 141nF or 47nF each.

3.) Try changing the coil to coil distance see if this helps also.

Hi,

Thank you for help.

1. using another transmitter (ZENS brand) solved the problem. I will try other baseus unit on Monday to confirm this was just bad unit or bad model. To make it more clear.

2. Coil is tuned. Ls' at 100khz is 16.7uH according to datasheet. so C107.108.109 gives 150nF total now to make it in resonance. Anyway that was from begining

3. Distance change makes no difference.

I will keep you updated about different baseus transmitter.

I was still unable to obtain another baseus unit, so not marking as solved to make sure that problem was really found.

can you send scope capture of startup with good unit?