lm25101 bootstrap capacitor

Markus Hoffet

Hello,

I plan to use an LM25101A gate driver in a Buckconverter application.

Is the value RD on page 5 in the data sheet to understand like a series resistor with the Bootstrap diode? Are there any min and max values for the bootstrap capacitor? I have 44V on the buckconverter input, 14V on the output and 14V as VDD for the driver. I am using infineon BSC039 MOSFETs with a total Gate chate of 32nC.

Thanks for you reply

Markus

over 11 years ago

0 Ryan May over 11 years ago

TI__Genius 13700 points

Hello Markus,

The Rd in the datasheet provides a characteristic of the bootstrap diode. Here is a short document that explains that characteristic. Nothing to be worried about.

http://webench4.ti.com/appinfo/webench/led/Rd.pdf

For sizing you bootstrap capacitor I would recommend looking at these other E2E posts that discuss the selection and provide links to some additional material on the matter. Conveniently one boot strap is much like another so while the parts are different the same concepts apply.

http://e2e.ti.com/support/power_management/isolated_controllers/f/188/t/200576.aspx

http://e2e.ti.com/support/power_management/isolated_controllers/f/188/t/278843.aspx

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lm25101 bootstrap capacitor