BQ24296: BQ24296MRGER USB Issue

Also I do not see the battery charging. Am I missing anything here?

Hi Ning Li Can you please help here?

Juan Ospina can you please help here?

Also when battery is present and when I unplug USB, for a short time period I see the power supply resetting.

Hi Shyam, 

Can you please help to provide a waveform showing VBUS, VSYS, and VBAT for the scenario of no battery charging as well as no power to SYS. If possible it would also be helpful to review the status of all registers. 

Best Regards,

Garrett 

Hi Garrett,

Thanks for the reply.

I am a hardware engineer and trying to run this charger autonomous, with very little or no FW support.

PSEL is pulled up to REGN

OTG to MCU with no pull up or pull down

CHARGER_EN is pulled up to 3.3V 

Initially battery is connected to the system and when USB is plugged in, I see VSYS dropping down to 1.6V, staying at 1.6V and no REGN.

What should be the connections to make power path work seamless and also to charge the battery when USB is plugged in with no FW effort.

Also, is there anyway to do VBUS detect by reading registers?

Thanks,

Shyam

Hi Garett,

It did not, I had to pull the OTG pin to ground. Still I am not able to charge.

How about the PSEL pin as well?

Hi Shyam, 

Apologies I see it was not mentioned in the previous schematic review, but can you try disconnecting PSEL from REGN and either connect it to GND or pull up to USB voltage. 

Section 9.3.1.3.1 on page 19 of the datasheet mentions required conditions for REGN to turn on. Expectation is after USB input is applied REGN will turn on before Vsys and then charge begins if CE is pulled low. Please confirm a valid input voltage can be observed at VBUS pin.

Best Regards,

Garrett 

Hi Garett,

There us valid voltage on VBUS.

So you are saying if I pull PSEL to GND and OTG to GND and CE to GND, charging should happen?

Thanks,

Shyam

Hi Garrett Kreger,

I pulled PSEL to GND, OTG to GND, CE to GND, VBUS is at 5.02V, REGN reads ~3.9V, TS reads ~2.24V.

Still battery not charging.

Any help here at the earliest is appreciated. Do I need to control the registers?

Thanks,

Shyam 

Hi Garrett,

Can you please help here. I am kind of stuck here.

Thanks,

Shyam

Hi Garrett,

To add, I have pull-ups on SCL, SDA and INT lines, does this mean the device is expecting some register changes?

Thanks,

Shyam

Hi Shyam, 

Shyam Thillainathan said:

I pulled PSEL to GND, OTG to GND, CE to GND, VBUS is at 5.02V, REGN reads ~3.9V, TS reads ~2.24V.

For this test were you able to confirm expected voltage at SYS? What is the status of STAT and PG pins?

Host interaction with the registers should not be required for the battery charger to function, but if you have the ability to check them it will be beneficial for further debugging. Even with SCL, SDA lines connected to pull-ups the device is not expecting register changes to function. 

Best Regards,

Garrett

SYS reads 3.283V

STAT is 3.3V

PG is 2.754V

Hi Shyam, 

It appears you still have a hardware setup issue in your test (or your IC has possibly been damaged). SYS read 3.283V indicates rail is still being powered from battery and not the buck converter. 

With 5V VBUS applied and no register modification SYS should be regulated to approx. 3.5V (SYS_MIN default is 3.5V) and REGN voltage should be approx. 4.8V. In my lab testing REGN = 4.86V with 5V VBUS. For your reference VREGN spec is on page 10 of the datasheet. 

Best Regards,

Garrett