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# bootstrap capacitor IR2110 and IRF540

Hi all, I am trying to make a full bridge inverter for this, I am using the IR2110 controller and the Mosfet IRF 540, but I don't know how to calculate the starting capacitor, I have followed a guide to calculate this, but I am in doubt. VLS appears in the formula = Voltage drop across the low side FET (or Load for a high side driver), but I don't know where to look it up in the datasheet or where I can look at this. as well as VMin = Minimum voltage between VB and VS, I would appreciate your help, thank you very much I follow the dt98-2a-Bootstrap Component Selection For Control IC's guide.

The frequency I am using is 25KHz but my question is how do I see or where do I find Vls and Vmin according to that formula in which part of the tab or how, thanks

1 Solution
Moderator
Moderator

# Re: bootstrap capacitor

Vmin is VBSUV- in datasheet. For IR2110 you can choose 9.5V.

5 Replies
Moderator
Moderator

# Re: bootstrap capacitor

We have another AN which explains bootstrap circuit calculation with examples:

https://www.infineon.com/dgdl/Infineon-Using_Monolithic_Voltage_Gate_Drivers-AN-v01_00-EN.pdf?fileId...

Very common range of values for Cboot is between 1 - 10uF for 25kHz switching, you can also choose 2uF or 3uF, every capacitor should work just fine.

Br

YF

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# Re: bootstrap capacitor

Thank you very much I was sure I had written it in English, I have changed it.
I saw your answer, thanks for the information you provided, but by any chance do you know about vls and vmin in the above document, I don't want to be left with that doubt of how to get those values or in which part of data sheet I can find them.
Anyway I will follow the guide you sent me, but if someone knows is open the question, thank you

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Moderator

# Re: bootstrap capacitor

Vmin is VBSUV- in datasheet. For IR2110 you can choose 9.5V.

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# Re: bootstrap capacitor

dear @yiye_4841451
thank you very much for your help, thank you very much, thanks to this image I understand where to get the value of vmin and how to interpret it which is the important thing, I would only be missing "VLS" and that's it.

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