BQ24600: Chip Heating Up

Kushal Ramdas

Prodigy 40 points

Part Number: BQ24600

Hi, I am designing a charger using BQ24600.

Input: 24V 4A.

Output/Charging battery at 16.8V, 2A. The Mosfets and charger IC get very hot, only after a few minutes.

Is there something I missed in the design? Please check, I have attached design files.

Note: SIR418 used instead of SIR426. Thanks,

over 5 years ago

0 Kedar Manishankar over 5 years ago

TI__Mastermind 24075 points

Hi Kushal,
I will provide you with layout tips, and an explanation of key considerations due to high switching frequency of BQ24600 as soon as possible.

0 Kushal Ramdas over 5 years ago in reply to Kedar Manishankar

Prodigy 40 points

Hi Kedar, Thank You.

0 Kedar Manishankar over 5 years ago in reply to Kushal Ramdas

TI__Mastermind 24075 points

Hi Kushal,
The power dissipation on the IC is mainly resulted from LDO, gate driver to drive the FETs with high frequency. PCB needs to have enough copper areas for the heat to be dissipated. The power loss from the power stage also needs copper areas to dissipate. Reducing the input voltage can help reduce both charger IC and power stage (MOSFETs) switching power loss. We don't have quantified data for this as the results are also related to the MOSFETs' gate charge. 4 layer board is recommended over 2 layer board to help with thermal dissipation as this charger has a high 1.2MHz switching frequency that contributes to higher switching losses. Another way to reduce switching loss is to use lower Qg FET for HSFET and LSFET.

0 Kushal Ramdas over 5 years ago in reply to Kedar Manishankar

Prodigy 40 points

Hi Kedar,

I do have copper areas for the heat dissipation. I also have a FET with a very low Qg. But let me try 4 layer with more copper areas, or lower input voltage. This should help. thanks for the assistance.

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BQ24600: Chip Heating Up