BQ51013B: Charge Current Low

When you load the bq51003 with a resistive load at OUT, do you still see 5V at 60mA?
For this test do not load the bq25100.

Ok, so i make again my test. what i see is 90mA of current going to the battery when it is the bq51013 that give current to the BQ25100. (not 60 mAs as i said before). But when i put directly the power on the bq25100 the charge is correct : 200mA.

So i come back to your test.
I remove the battery from the bq25100.
I put a resistive load at OUT of the BQ51013, and i look to the current going through this resistor.
- 47ohm give me current around 90mA
- 20ohm give me a current around 250mA :-).....

So the wireless parst seems able to deliver the requested current ! But it does not do it when this current is requested by the bq25100 ?

Thanks for running the test.
Each of the two circuits seem to be working.

When the two circuits are connected:
1.) What is DC voltage out of the bq51003 when bq25100 is only supplying 90mA?
2.) Is Communications current limit enabled/disabled (EN1 / EN2 configuration)?
3.) What is noise level on voltage out of the bq51003?

1) 5V between the bq51013 and the bq25100

2) EN1/EN2 are plugge to the microprocessor, but on microprocessor side not yet configured, so should be pull down internally by the bq51013

3) the 5V seems ok, no noise found.

Another remark, i found that the bq25100 switch fast to low charge current. When this one is already switching, if i put the battery on an external charger the charge current is not yet reduce (voltage seen by my external charger is 3.8V).... strange that bq25100 go already to lower end charge current at this step. But i don't think this problem is linked to the charge current low in wireless mode.

Finally today , i get same problem of low current (60mA, then 50mA... slowly going down) whit 5V directly put on input of the bq25100. It seems that the problem is on this side.... I don't success to see the 200mA today (but i already seen then !!!!)...

Here my schematic around the bq25100:

A couple of things to look at:

1.) Try removing C33, 1uF cap on TS pin

2.) Try replacing RT2 with a 10k resistor

3.) What is voltage on ISET pin vs voltage at OUT

4.) Send layout file for review.

1) Removing C33 does not have any impact.

2)

- With RT2 (without C33) : 32ma on Out (yes i am not always around 70 or 90)

- Replacing by a 10k : 32ma too

- Remove RT2 (no RT2 , no 10k, no C33) : 52 ma !!!

3) Test made with RT2 replaced by a 10k 

    - Voltage on ISET : 280mV

    - VOltage on OUT : 4,07 V (for information i get also this last voltage without battery connected)

4) i wil try to send it later

But i success again to have a 200mA current to the battery :-). With the 2  methods: 5v suplied directly to the bq25100 or with the wireless part :-) 

TO success to do it, i need to put a "total" discharge battery (i discharge it with a tool to 3V.)

I succes to charge totally the batteyr this ways (1h15 for my 250mA batterry)

I need to investigate, but i think that if i put a battery "middle" discharge, the full charge does not start and i am in this case between 32ma and 90 of current.

One possibility is solder issues on the IC, open or intermittent pins. Are you seeing the same problem on more than one unit?