Timeline for How can I measure gate capacitance?
Current License: CC BY-SA 3.0
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| when toggle format | what | by | license | comment | |
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| Aug 26, 2015 at 6:46 | comment | added | scanny | After further research, I've learned that the "10x threshold" part of the graph is known as the Miller plateau. Also I learned that my circuit won't reach that level, because that breakpoint indicates where the drain voltage begins to drop because the current compliance of the source behind it is exhausted. Since I'm staying in the linear region where the source voltage remains constant, it seems I'm at least safe from that big bump in incremental capacitance :) | |
| Aug 24, 2015 at 3:44 | vote | accept | scanny | ||
| Aug 28, 2015 at 21:46 | |||||
| Aug 24, 2015 at 3:43 | comment | added | scanny | This is very interesting indeed Dave. I think I'm coming up against this very "10x threshold capacitance" (or whatever it would be called) that you mention. I was able to largely overcome the \$V_{DS}\$ stability dependence I identified with the help of Spehro's answer, by substituting a lower capacitance MOSFET. But now I'm getting a 500kHz oscillation right around 4.35V \$V_{GS}\$ (\$I_{DS}\$ = 400mA) and continuing until \$I_{DS}\$ gets to about 2.4A, at which point it very abruptly disappears. This is certainly consistent with this chart. I think it's time to add a driver stage :) | |
| Aug 22, 2015 at 23:56 | history | edited | Dave Tweed | CC BY-SA 3.0 |
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| Aug 22, 2015 at 20:59 | history | answered | Dave Tweed | CC BY-SA 3.0 |