BQ24650: about FETs

ACGUY

Part Number: BQ24650

Hello E2E,

When it using high current FET, the bq24650 can't drive FETs normal. However, the bq24650 can operation when change the FETs to small parasitic capacitance.

Question;
Does this device have restriction for FETs characteristic?

Regards,
ACGUY

over 4 years ago

0 Michael Emanuel35 over 4 years ago

TI__Mastermind 40705 points

Hello,

In the datasheet in Section 9.2.2.4 it says the gate drive voltage provided is 6 V. Additionally, the turn-on and turn-off resistors are attached below:

If you cannot charge/discharge the MOSFET capacitance fast enough you will be unable to switch the MOSFET at the 600 kHz switching frequency.

Please choose a device that the BQ24650 can switch fast enough for correct operation.

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

0 ACGUY over 4 years ago in reply to Michael Emanuel35

Guru 11170 points

Hello,

Thank you for reply.

Could you provide a specific upper limit for capacitance?

Regards,

ACGUY

+1 Michael Emanuel35 over 4 years ago in reply to ACGUY

TI__Mastermind 40705 points

Dear ACGUY,

Please select a MOSFET with parasitic capacitance that will allow the turn on/turn off of the MOSFET in the appropriate time. I suggest looking into the charging/discharging equations of a capacitor to start.

Please see the attached link for more information on gate drive circuits:

https://www.ti.com/lit/ml/slua618a/slua618a.pdf

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

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BQ24650: about FETs