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I am designing a boost converter for wind turbin, with load 12Vdc, 2A. Before I install my boost converter on my windturbin, I putt a test to make sure it work properly. So I use this circuit to simulate noload test

the battery represent power supply and I use tip142 as the gate driver. with no load circuit, the boost converter is working. but when I add load, like the circuit bellowload test

it's not working, there's no boost effect measured. power supply work in current mode in low voltage. Is it because the gate driver? Do I really have to use bootstrap? or something else?

Thanks,

Rani Purbasari
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    The NPN transistor is backwards, and there is nothing to ever turn off the FET. Also, please PLEASE [clean up your schematic](http://electronics.stackexchange.com/questions/28251/rules-and-guidelines-for-drawing-good-schematics/28255#28255). – Connor Wolf Apr 25 '15 at 18:25

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You are completely driving your MOSFET incorrectly. Firstly there is no postive voltage source that can turn on the device and secondly the BJT will not work to pull-down the gate voltage to zero on alternate half cycles of any PWM signal you might apply.

If you tried connecting the NPN BJT's collector to your micro controllers Vcc then you have the basic means to activate the FET but you still need something that discharges the FET's gate capacitance when deactivating.

You should also look to see if you can find a MOSFET that can be adequately driven with a logic level voltage - if not then you should consider using an intermediary voltage (maybe 8V) to power a driver that can properly switch the FET on and off at the PWM rate.

Andy aka
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