Hello
Please we have a problem in the production version of our product.
We used the same schematic in the board we designed for internal tests, it worked correctly, but when we redesigned the PCB, the IC stopped to work.
WHEN WE CONNECTED THE BATTERY, THE SYSTEM WORKS PROPERLY, WHE WE CONNECT THE USB CONNECTOR, THE CHARGER DON'T WORK AND THE SITUAZIONE IS AS FOLLOW:
- The /PG is low, but every 250msec return high for about 10 msec.
- The state output is high fix.
This is the schematic.
Note:
- C33 is in reality 44uF, R8=R7=470 ohm, OTG is floating (we tried also with a 10k pull down, but nothing changes, and in the first PCB for internal test worked with OTG floating).
- we have tried with D+ & D- connected to USB connector, connected with 200 ohm together end connected with 0 ohm together, same result
- In the PCB for internat tests, L2 was 4,7uH, and it worked, but didn't work in the new PCB, so, given that you didn't suggest to use inductors greater than 2,2uH, I passed at 1uH in the new PCB
Herewith are some screen shots of signals in different zoom views.
Vbat and vsys seems to be 5 V cause limitation of my digital oscilloscope, but really they are 8V as they had to be.
If you can't see exactly the labels of the screen shots, they are (from top to down) VREGN, VBUS, VBAT, VSYS, VPMID, VSW
I read that if the VREGN doesn't start (as I suppose happens in my circuit) it can be cause the source NOT VALIDATED, but I don't see any problem in the VBUS signal.
Moreover, I tried to give with a power supply directly 5V near to the circuit, but nothing changes.
If I could I 'd return to the PCB made for internal testing, but we are limited by the plastic enclosure of the product.
Please can you tell me which can be the problem???
Thanks and best regards.