BQ25792: BQ25792 HEAT about

SWENGWOO LEE

Part Number: BQ25792
Other Parts Discussed in Thread: USB-PD-CHG-EVM-01,

I am using usb-pd-chg-evm-01 .

However, the BQ25792 gets quite hot when charging the battery at 2A.

I want to know the temperature according to the charging current of the bq25792.

Also, I want to know if the temperature of the BQ25792 is above how many degrees it operates normally.

over 1 year ago

0 Jeff F over 1 year ago

TI__Guru*** 143950 points

Hi Swengwoo,

IC heating is a function of power losses and heatsinking though the metal that the IC is solder too. The datasheet thermal table has RthetaJA in degrees C/W which can be used to estimate the chip heating but it is only helpful if the PCB is of a very specific type and size. If you can provide the input voltage voltage, battery voltage and load on SYS, I can look through EVM thermal data for a similar setup.

Regards,

Jeff

0 SWENGWOO LEE over 1 year ago in reply to Jeff F

Intellectual 270 points

Thank you for answer.

I am using a 4S1P battery and the voltage is 12.8V~16.8V.

VSYS=12V

USB C Type Input Voltage= 5V.

USB C Type Charging Current = 2A

I am setting like this.

0 Jeff F over 1 year ago in reply to SWENGWOO LEE

TI__Guru*** 143950 points

Hi Swengwoo,

On the EVM, with VBUS=5V and max IINDPM=3.3A, max charge current for VBAT=12V is 1.5A with gives TDIE = 120C and for VBAT=16V is 0.9A with gives TDIE = 120C.

Regards,

Jeff

0 SWENGWOO LEE over 1 year ago in reply to Jeff F

Intellectual 270 points

HI
When tdie = greater than 120c, does the BQ25792 breaken?

0 Jeff F over 1 year ago in reply to SWENGWOO LEE

TI__Guru*** 143950 points

Hi Swengwoo,

The charger has thermal regulation loop that throttles back the input current when the die temp reaches the thermal regulation temperature set in the I2C register. The highest and default value is 120C. The IC is rated for up to 150C max.

Regards,

Jeff

0 SWENGWOO LEE over 1 year ago in reply to Jeff F

Intellectual 270 points

thanks for the answer

Do you have any heatsinks you would recommend for the bq25792?

+1 Jeff F over 1 year ago in reply to SWENGWOO LEE

TI__Guru*** 143950 points

HI Swengwoo,

Unfortunately, I do not. Taking heat from the top of a QFN plastic package typically does not help much. The heat is expected to be removed through the IC pins being soldered to large copper planes.

Regards,

Jeff

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BQ25792: BQ25792 HEAT about