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The issue regarding the maximum switching frequency of the driver board and the switching tube

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yxj34825
yxj34825 Contributor Level 1
in Module Products

We have purchased your company's driver board CGD1700HB2M-UNA and 2300V switch tube CAB7R5A23GM4. We have formed an inverter bridge with two switch tubes. However, our test requires the emission of high frequency, that is, a very high switching frequency. When we emit up to 300kHz, the waveform at the DS terminal has already shown some distortion. Our dead time is 600ns. Is there any data indicating the maximum frequency that can be emitted? We hope you can help me answer this question. Thank you.

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  • Forum_Moderator
    Forum_Moderator Wolfspeed Employee - Contributor Level 5
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    Thank you for your post, it has been approved and we will respond as soon as possible.

  • ChrisN
    ChrisN Wolfspeed Employee - Contributor Level 3
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    Hello yxj34825,

    The maximum switching frequency of the gate driver and power module pair is governed by the gate driver's onboard isolated DC/DC converter and the gate charge of the power module. The appropriate calculation is shown in Section 9 of the CGD1700HB2M-UNA datasheet and repeated below. Substituting the values for the CAB7R5A23GM4 and the CGD1700HB2M-UNA, the maximum switching frequency is only 178 kHz. For your application, I would recommend decreasing the switching frequency.

    Relevant Equations from Gate Driver Datasheet:

    image.png

    Calculations Applied to CAB7R5A23GM4 Application:

    image.png

    Thanks,

    Chris N.

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