Hi, I fried now four BQ25792 chargers, to the extent that it produces real flames!
This happens during charging via USB-C PD of a LiFePo4 battery when the battery is getting full.
Then the VBAT_OVP_STAT stats flag turns on and seconds later the chip burns.
Relying on the MCU to set CHG_EN to zero is too much risk. I would expect that battery over-voltage protection actually protects by itself and does not rely on the MCU. however, in reality it burns down and even kills the MCU every time by putting an overvoltage onto I2C. Four ESP32 S3Pro are dead too.
Any suggestion? This should not happen at all and without a robust solution I cannot recommend using this TI chip for any project.
settings written by MCU after startup in this sequence:
* CE off on MCU startup and keep it off while writing configuration to registers
* Cell-count 4S
* ADC control enabled
* Charging current control enabled
* SYS voltage limit 12V
* BAT voltage limit 14.5V (LiFePo4 battery top-off voltage; the TI chip fried with lower voltage goals too)
* BAT current limit 1A
* Input voltage limit 20V
* Input current limit 3A
* HVDCP enabled (connected to USB-C PD resulted in 12V/1.5A mode)
* CE on (after settings written), and CHG_EN bit also enabled
MCU runtime:
* reading voltages and fault status
* BAT_OVP
BQ25792 fries - Charger 25 Click
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BQ25792 fries - Charger 25 Click
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- IvanJeremic
- mikroElektronika team
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Re: BQ25792 fries - Charger 25 Click
Hi,
This is concerning, correct me if I understood incorrectly, if you attach a battery that is already fully charged the click board gets burned?
We have had fully charged batteries connected to this click board, but this click never got burned.
Does the STAT led start blinking before the board gets burned?
Regards,
Ivan.
This is concerning, correct me if I understood incorrectly, if you attach a battery that is already fully charged the click board gets burned?
We have had fully charged batteries connected to this click board, but this click never got burned.
Does the STAT led start blinking before the board gets burned?
Regards,
Ivan.
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Re: BQ25792 fries - Charger 25 Click
Yes, the stat led started blinking too. And i had a V-meter on VSYS which spiked wildly.
I have now added a 220uF/36V electrolyte capacitor to VSYS in the hope that this supresses voltage spikes that likely kills the chip. still testing.
Thx!
I have now added a 220uF/36V electrolyte capacitor to VSYS in the hope that this supresses voltage spikes that likely kills the chip. still testing.
Thx!
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- Posts: 3
- Joined: 17 Mar 2024 12:13
Re: BQ25792 fries - Charger 25 Click
yes, id did blink in irregular patterns.IvanJeremic wrote: ↑17 Mar 2024 21:28Does the STAT led start blinking before the board gets burned?
Regards,
Ivan.
I added a 220uF electrolytic capacitor now to VSYS and see whether this helps.
Thx!
- IvanJeremic
- mikroElektronika team
- Posts: 316
- Joined: 05 Sep 2022 14:32
Re: BQ25792 fries - Charger 25 Click
Hi,
Can you tell me if the capacitor solved the issue?
Can you send me some sort of specifications for your battery (datasheet or something similar)?
Regards,
Ivan.
Can you tell me if the capacitor solved the issue?
Can you send me some sort of specifications for your battery (datasheet or something similar)?
Regards,
Ivan.