kender
Advanced Member level 4
H-bridge. Diodes in series with MOSFET gates. What are they for?
Folks,
Sometimes a resistor is added in series with MOSFET gate. Together with gate capacitance, it forms an RC, which slows down the turn on of the MOSFET, which sometimes is useful. On the web, I saw several schematics of H-bridges having a diode parallel to the resistor. See an example below.
In this picture, the diodes in question are MBR150 in series with 100Ω resistors. What are they for?
My guess is that they make the MOSFET turn on more slowly than turn off. This is a kind of a dead time generator, which prevents a vertical shoot-through. What do you think?
Any suggestion, insight or reference is really appreciated!
Cheers,
- Nick
Folks,
Sometimes a resistor is added in series with MOSFET gate. Together with gate capacitance, it forms an RC, which slows down the turn on of the MOSFET, which sometimes is useful. On the web, I saw several schematics of H-bridges having a diode parallel to the resistor. See an example below.
In this picture, the diodes in question are MBR150 in series with 100Ω resistors. What are they for?
My guess is that they make the MOSFET turn on more slowly than turn off. This is a kind of a dead time generator, which prevents a vertical shoot-through. What do you think?
Any suggestion, insight or reference is really appreciated!
Cheers,
- Nick
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