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TPS28225: Reverse diode for gate drive

na na78
Guru 16770 points
Part Number: TPS28225

Hi

The customer is assuming to insert reverse diode at gate of FET for reduction ringing like following image.

1.

In common, what kind of diode should be selected for such usecase?

2.

Is there problem if reverse diode and gate resistor is inserted at both of high-side and low-side?

(Inserting to high-side only is popular?)

3.

Regarding to use of reverse diode, could you please tell us if there is a point to be considered?

BestRegards

  • 0
    TI__Genius 12990 points
    Hi nana,

    Good to hear from you, thanks for reaching out to us about this diode selection. Im an apps guy and will help you out.
    This diode is meant to pull the gate of the FET down to ground faster bypassing the gate resistor. This means that during turn off most of the power dissipation will be internal to the driver. The main point of the diode is to quickly turn off the FET so this diode should have a small ON resistance for higher sink current capability. Its also a good idea to keep the parasitic capacitance low for this reason. Low forward voltage schottky can be used to limit the risk of miller turn on this way the current fully flows through the diode and not the gate resistor during turn off.

    Check out section 3.4.1 of www.ti.com/.../slua618.pdf
    Thanks,