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LMG3422R030: Reverce Conduction (Third quadrent) Characteristics

Yajush Sihag
Prodigy 10 points
Part Number: LMG3422R030

Tool/software:

In my application, TI LMG3422R030 need to operate in third quadrant. What is the voltage drop at 5A, 10A, 15A and 20A when IN pin is high and switch is operating in third quadrant (Reverse conduction). Is it same as drop at first quadrant (Forward conduction)?

  • +1
    TI__Prodigy 540 points

    Hi,

    When IN pin is high, the voltage drop will be IFET x Rdson. For the duration when IN is low and the FET is operating in third quadrant, you can refer the curve Fig. 5.6 in the datasheet of LMG342x.

    Thanks & Regards,

    Ruchika

  • 0 in reply to Ruchika Sinha
    Prodigy 10 points

    Thank you for your response. I agree with your point, but I noticed that in the LMG3422R030 (as shown in the functional block diagram of the datasheet), a Si FET is connected in series with the direct-drive GaN FET. I am wondering whether the body diode of the Si FET could affect the overall GaN FET’s voltage during reverse conduction. Could you please confirm this?

  • +1 in reply to Yajush Sihag
    TI__Expert 7583 points

    Hi Yajush,

    We designed it in a way that the series Silicon FET is always ON when the VDD is applied to the device hence during the reverse conduction the body diode voltage doesn't show up. However, when VDD is not applied, the Qrr of the body diode comes into effect.

    Hope that answers your questions. Please click the green button if your question is resolved.

    Best,

    Pratik A.