nelly1
Junior Member level 3
I use two same mos diode(G and D connected mosfet which acts like diode) stacked as normal free wheeling diode. The symbol is like the pic1 below because they are insulated mosfet with pwell/dnwell and dnwell/psub junction diodes.
The problem is
1.when the diode is reversed biased, their voltage drop (VDS) are not the same,whatever the mosfet size is large or small..
2.when i add a VDC=Vth between the G and D of the lower mosfet to decrease the forward voltage drop, (when the diode is forward biased and current is small, Vgs=Vth, Vout=Vin-vth), why the reverse voltage drop of the lower mosfet increase?
REALLY NEED SOMEONE HELP!!!!!!!!!
The problem is
1.when the diode is reversed biased, their voltage drop (VDS) are not the same,whatever the mosfet size is large or small..
2.when i add a VDC=Vth between the G and D of the lower mosfet to decrease the forward voltage drop, (when the diode is forward biased and current is small, Vgs=Vth, Vout=Vin-vth), why the reverse voltage drop of the lower mosfet increase?
REALLY NEED SOMEONE HELP!!!!!!!!!
Attachments
Last edited: