Bootstrap Capacitor Calculation Problem - help

[Maverickmax]

Hi

I am currently learning how to calculate the bootstrap capacitor for IR2110 Application. So far I have identified every parameters apart from one:

Qgate 27E-06
Frequency 21600
Icbs(leak) 0
Qls 5.00E-09
Vcc 14
Vf 0.78
Vls 4.5
Iqbs(max) 230E-06
Vmin ??

I use the forumla from Application Note AN-978 on page 6. At the moment I am not certain on how to obtain Vmin, I use a half bridge configuration and the voltage is about 100V and the IGBT is IRG4BC20UD.

Please explain me how to obtain Vmin?

 

[bishal]

See here for Vmin calculation: https://electronics.stackexchange.com/questions/18423/bootstrap-capacitor-selection-with-ir2110-3

 

[FvM]

See here for Vmin calculation

Obviously, Google isn't able to distinguish confuse posts from real answers to a question....

There are actually two parameters that determine Vmin:
- IR2xxx undervoltage lockout threshold
- required minimum Vgs for safe operation
The larger value of both plus a safety margin is your Vmin