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I'm working on a SEPIC DC-DC convertor, in the reference design from Texas instrument there is MOSFECT which is derived by DR pin of the main controller (LM3488) as follows: enter image description here

There is an diode (D4), which is parallel with a 0 Ω resistor. My question is what is the point of this resistor (R34)? (practically the diode is shorted by the resistor, but apparently there is a reason for having this resistor).

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    \$\begingroup\$ I wonder why someone downvoted this question, it seems perfectly fine to me. \$\endgroup\$
    – marcelm
    Commented Jun 30 at 8:54

1 Answer 1

Reset to default
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The resistor is there so that you can slow down the turn-on of the FET if you want to, by changing the value from zero to something else. The turn off would be faster since the diode would conduct on the falling edge of the gate drive.

You might want to do that if you have trouble with the current sense ringing for example, or if you have EMI problems. Otherwise keeping the resistor at 0 ohms will result in the highest efficiency.

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