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Old 04-25-2012, 08:29 PM
cinan cinan is offline
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Join Date: Dec 2011
Posts: 58
Improoved MOSFET driver

Driving MOSFET properly is not so easy. Each MOSTET needs certain driving current, which is dependent
on gate chagre (Qg) and frequency and demand on driving circuit is increasing wif frequency.
Higher frequency, bigger driving current is needed to "fight" gate capacity. Proper current
will ensure steep raising edge of impulse, and this is what we need. This boosting is specially needed
when MOSFETs are paralelling, as total gate capacity is Qg1 + Qg2 + ..Qgn. So goal is to choose
MOSFET with low Qg and low Rds as silicon power disipation is dependent on current and Rds.

In att. you have oscillator circuit posted before by Mad Scientisct with corrected error in wiring
and booster stage for MOSFET. This solution is low side, single phase only. For tests you can basically
use any generator and boost his output via any MOSFET driver. In this case MCP1406 from Microchip.
See datasheet for connection details. There are other low side driver circuits (inverting/non inverting)
on the market and yu just need to pick proper one. See Farnell or Digikey for additional info.
MCP1406 / IR4426 / TC4427 / etc...

Cinan
Attached Files
File Type: pdf Driver_Boost.pdf (74.1 KB, 184 views)
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