BQ25700A: Unable to charge the battery

Hi Usama,

I will review your schematic and check the register settings and get back to you by tomorrow.

Regards,

Jacob

The previous schematics did not have values viewed.
Here is one with values visible

Hi Usama,

Make sure the ILIM_HIZ pin is not tied to ground. It stops switching when ILIM_HIZ pin is pulled low.

Regards,

Tiger

Hi

ILIM_HIZ is not tied to ground. It just has a test point so i can measure the voltage on it.
It was at 3.8V when left floating

Hi Usama,

I would suggest following the user guide found at https://www.ti.com/tool/BQ25700AEVM-732 as a starting point. From the information you have provided, I can not pinpoint where your setup might be going wrong. 

Regards,

Jacob

Hello 

I have an update

We decided to test it without the battery connected and there was no system voltage. This led me to believe that there needs to be system voltage present for the ic to be able to charge the battery otherwise the conversion is not working.

Also noticed i had a mosfet flipped

I fixed that and started again. There is still no system voltage. 

Here are the steps i followed tring to get system voltage

1. Disable external ilim

2. set minimum system voltage

3. set system input current limit

4. Enable adc for every 1 second and enable voltage read.

Hi Usama,

Could you post your switch node waveforms? 

Regards,

Jacob

Hi jacob by switch node waveforms. you mean the scope outputs of the gates of all mosfets? will post them in a bit

I also made the following changes
1. Tie en_otg to gnd
2. tie ext_ilim to regn

SW1 and SW2 waveforms

these are hidrv1 and lodrv1 waveforms. I think i might have an issue with bootstrap capacitance. i'll keep u posted

Hi Usama,

From the waveforms, it looks the converter did not start up correctly, I would like to suggest you getting a BQ25700AEVM and follow the user guide to evaluate the charger. It also serves as a reference to your application.

Regards,

Jacob