BQ24650: BQ24650RVAT: high current peak when the mosfets switch and one mosfet burnt

As I am not sure the first picture appears, here is the picture:

Hi Aurelie,

  WHt is the part number for your switching MOSFETs?

Hello Kedar,

The switching mosfet is SVD5865NLT4G

Best Regards

Hi Aurelie,

   Can you add a resistor between BTST pin and C112 and re-test? The resistor is equivalent to R14 in the evm user guide.

Dear Kedar,

I have patch th eboard and test it again. I observe this kind of signal on the Q12 gate, and also on the point between D16, C112 and the new resistor:

The charging doesn't work anymore.

Hi Aurelie,

  The attachment did not come through. I cannot see the image.

Dear Kedar,

I hope the attachment will work this time.

regards

Hi Aurelie,

   It looks like there is a problem with the gate drive. The signal is not switching on/off the MOSEFT strongly. HIDRV is supposed to be driven by BTST (VBTST = VIN + VREGN) w.r.t GND, so the VGS of the HSFET is driven strongly by REGN. The LSFET is to be driven by REGN directly, so VGS = REGN as source of LSFET is referenced to GND. It is likely that this issue is causing slow turn off of the HSFET which is causing shoot-through, as there are brief instants with both HSFET and LSFET on, which is a low resistance path from the adapter to GND. This is not ideal. I would recommend re-visiting your layout and focusing on the layout of HIDRV and LODRV. You should use short clean traces, without routing too much through multiple layers, and also avoid routing near the short wide high frequency PH trace.

I would also recommend obtaining a BQ24650 EVM and configuring for your system conditions, and test.