BQ24610: Vgs waveform fault for high-side mos

user5112180

Part Number: BQ24610

Hi,

When I test BQ24610 circuit, I found a voltage fall back when high-side Vgs is lifting, is there a way to avoid? ps: hide-side mos: NTMFS4941NT1G, low-side mos: NTMFS4935NT1G

over 6 years ago

0 Jing Zou over 6 years ago

TI__Mastermind 20240 points

Could you please mark what each wave form is? Are they all tested under the same condition?

0 user5112180 over 6 years ago

Prodigy 210 points

Hi, Figure 1,6,7,8 are for VGS fault on high-side mos, Figure 2 is for schematic, Figure 3,4,5 are for VDS. And and figures were tested in same condition.

0 Jing Zou over 6 years ago in reply to user5112180

TI__Mastermind 20240 points

Can you please share the layout? Especially on the converter part of the circuit.

0 user5112180 over 6 years ago in reply to Jing Zou

Prodigy 210 points

This is 6 layers pcb, second layer is for GND, fifth layer is for POWER shape, gate pin for High-side and Low-side is in layer 3, SW in layer 4, BQ24610 MOS and Inductors are in top layer.

0 Jing Zou over 6 years ago in reply to user5112180

TI__Mastermind 20240 points

For best practice, it is better to have all power components on the same layer and use the ground layer as shield, especially all the switching elements.

From your waveform earlier, it looks like the voltage spike on VGS is highly likely caused by the parasitic inductance. It is highly important that you have your high frequency switching loop as small as possible. Below is an example.

Power management

Power management forum

BQ24610: Vgs waveform fault for high-side mos