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LMG2100R044: LMG2100R026 Single input control

HyunBae Jeong
Prodigy 60 points

Part Number: LMG2100R044

Tool/software:

Hello. My name is Steve, and I am designing with TI LMG2100R044.
Currently, I am operating GaN driver by inputting two different frequencies using LMG2100R044.
One is inputting 7.25MHz frequency and the other is inputting 2MHz frequency and operating GaN driver.
The circuit part that inputs 2MHz frequency and outputs GaN driver operates normally and can confirm the output,
But the circuit part that inputs 7.25MHz frequency and outputs GaN driver does not operate normally.
It operates as if it is shorted (consuming 3.5A momentarily), and there is no actual circuit short in the circuit or PCB.
It seems to be a dead time issue. If the dead time is increased significantly so that the 7.25 MHz signal does not enter the input of the GaN driver, even if a 35 V power supply is applied,
the IC does not experience overcurrent, but if the dead time is gradually reduced so that the 7.25 MHz signal enters the input, an overcurrent occurs that causes a short circuit.
The part that receives the 2 MHz frequency input can check the output because the GaN driver operates normally, but the part that receives the 7.25 MHz frequency input
I do not know why the GaN driver does not operate normally.

Please check.
Thank you.

GaN DRIVER SCH.pdf

  • 0
    TI__Expert 4520 points

    Hello,

    Thank you for providing the schematic, I do not see anything of concern at the moment.

    Can you provide me with more details about the deadtime you are using now?

    Do you also have any waveforms showing PWM signals and/or SW signals to help diagnose?

    Thanks,
    Zach S

  • 0 in reply to Zachary Soviero
    Prodigy 60 points

    to zachary soviero

    The waveform data according to the circuit operation is attached.
    As shown in the attached circuit diagram, the LMG2100R044 circuit is designed to be divided into two input signals, 2 MHz input signal and 7.25 MHz input signal, and the GaN driver of the 2 MHz input signal operates normally.
    However, the GaN driver of the 7.25 MHz does not operate normally. (The GaN driver does not switch accurately, and the IC dies due to overcurrent.)
    We have attached the tested file, and we have confirmed that the GaN driver with a 2MHz input signal that operates normally does not operate properly when we change the frequency to 7.25MHz.
    We have concluded here.
    We have confirmed that LMG2100R044 does not operate at 7.25MHz.
    Is this conclusion correct?
    The DATA SHEET states that it can operate up to 10MHz.
    Please confirm.

  • 0 in reply to HyunBae Jeong
    Prodigy 60 points

    TO zachary soviero

    I would appreciate a quick response.

  • 0 in reply to HyunBae Jeong
    TI__Expert 8568 points

    Hello Steve,

    Apologies for the delay. Zach is out so I'm jumping in. You're correct, it can operate max up to 10MHz frequency. Although the gate driver of the LMG2100R044 device is capable of driving the GaN FETs at frequencies up to 10 MHz, careful consideration must be applied to ensure that the running conditions for the device meet the recommended operating temperature specification. Specifically, hard-switched topologies tend to generate more losses and
    self-heating than soft-switched applications.

    You mentioned there is an over current event. I'm suspecting a shoot through here (probably due to noise or hard switching). Does the HS chip with 7.25MHz not switch to begin with? Have you tried doing ABA swap? Can you please send the layout for review. We'll debug this together.

    Best,

    Pratik A.