i want to know the usage of bootstrap capacitor in IR2110
following figure shows the bootstrap capacitor in IR2110 from its datasheet
Oh, thanks, I didn't see the figure at first. Mehdi, please tell me at first, does this circuit IR2110 have one or does it have two bootstrap capacitors? Then we can think about their rolls. Or do you know the answer already?
The bootstrap cap has to lift the potential for the gating signals of the upper and lower FETs. Is that known to you? This trick with the bootstrapping cap works with FETs only.
The bootstrap capacitor holds enough energy to supply the "HO" Driver circuit output while LO is off:
While LO is on (and HO off), the capacitor is charged from VCC.
When LO is off and HO on, the energy stored has to supply the high side Driver circuit.
This is a rather common "trick" when high side n-channel MOSFETs are used. It requires sufficiently high switching frequencies and not too-high on-times of the high side.
Hope this helps
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