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LMG1205: Is it possible to connect a bootstrap diode to the outside?

Part Number: LMG1205

Hello,

This device has a built-in bootstrap diode. Is it possible to add an external diode as shown in the figure below?

Best regards,

  • Hello Kaji-san,

    You can add an external bootstrap diode like you show. I would recommend referring to these sections of the datasheet that show the internal diode specs:

    One thing to keep in mind, is that the diode with the lower Vf will conduct more of the current. In addition, the Vf is inversely proportional to temperature, so parallel diodes can tend to have a positive feedback loop where one will conduct all of the current if the power dissipation is too high. For this reason, it is best to use a Schottky diode or diode with a low Vf, so your external diode can help conduct more current. Section 8.2.2.5 of the UCC27282 datasheet discusses this. It is for a different part, but the same ideas apply. 

    Many customers have added diodes like shown and had success. One thing that can help, is to add a placeholder for a resistor in series with the external diode, in case you need to limit the current drawn by that diode.

    Thanks,

    Alex M.