BQ24610: HIDRV PWM issue

Alexander Strokanov

Intellectual 450 points

Part Number: BQ24610

Hello!

The device setup is for charging 4 cell LiPo battery with 4A CC till 16.8V.

4,7 uH IHLP-5050FD series inductor

BSC010N04LS FETS in high and low sides.

Input pwr sply is 20 V (over 200 W power).

As result I have only 3 A charging current max, and HIDRV fet is heating (not very much but too hot for 3 A current).

Then I chenge setup for 2-cell battery and charge goes 4A.

Here is the oscilogram of HIDRV then battery is charging. What could be the reason?

over 5 years ago

0 Kedar Manishankar over 5 years ago

TI__Mastermind 24075 points

Hi Alexander,

HIDRV FET heating up is due to MOSFET gate driver power loss. Pic_driver_loss = VIN*Qg_total*fs. The current FET you have is rated for 100A and as a result has a high Qg. For 4A application a lower continuous drain current FET, with lower Qg can be selected, and this will decrease the power loss on the HIDRV FET.

0 Alexander Strokanov over 5 years ago in reply to Kedar Manishankar

Intellectual 450 points

Thank you! Would try to FDS8447 like its in EVM. If the result is not better, I will report here.

0 Kedar Manishankar over 5 years ago in reply to Alexander Strokanov

TI__Mastermind 24075 points

Hi Alexander,

Sounds good. I will close the thread for tracking purposes, and when you have new results feel free to update this thread. Note that this board was released while back, so it is possible to find better FET with lower Qg in the current market. It is not necessary that this FET is the most optimal FET

0 Alexander Strokanov over 5 years ago in reply to Kedar Manishankar

Intellectual 450 points

Oh, It will take couple of days to get other FEts, so I'll reply here if I get good results.

0 Kedar Manishankar over 5 years ago in reply to Alexander Strokanov

TI__Mastermind 24075 points

That is not an issue. Feel free to re-open the thread once you get results.

Power management

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BQ24610: HIDRV PWM issue