d123
Advanced Member level 5
Hi,
I want to use a BJT instead of a MOSFET in a DC-DC converter circuit, the type is even described as suitable for DC-DC due to its very low Vce(sat) in the datasheet blurb at the top. First need to see how well or not it fits into circuit with the maths. Also want to use same BJT to replace diode in converter circuit as Vf of BJT is ~150mV, Schottky is ~300mV, see this is possible and standard practice, synchronous rectifier it was called, if I remember term correctly.
Anyway, trying to plug the BJT into the formula for switch PD requires MOSFET Qg as one of the values - see attached image for formula.
Does anyone know if, as Coulumbs = current multiplied by time, it will be valid to change Qg/t = IG into IG * t = Qg > Ib * t = ~nC equivalent value as an approximate but useful/valid number to plug in to the PD formula?
If not, any suggestions on how to turn Ib and delay + rise time (or whatever is appropriate) into an equialent of MOSFET Qg?
Thanks.
I want to use a BJT instead of a MOSFET in a DC-DC converter circuit, the type is even described as suitable for DC-DC due to its very low Vce(sat) in the datasheet blurb at the top. First need to see how well or not it fits into circuit with the maths. Also want to use same BJT to replace diode in converter circuit as Vf of BJT is ~150mV, Schottky is ~300mV, see this is possible and standard practice, synchronous rectifier it was called, if I remember term correctly.
Anyway, trying to plug the BJT into the formula for switch PD requires MOSFET Qg as one of the values - see attached image for formula.
Does anyone know if, as Coulumbs = current multiplied by time, it will be valid to change Qg/t = IG into IG * t = Qg > Ib * t = ~nC equivalent value as an approximate but useful/valid number to plug in to the PD formula?
If not, any suggestions on how to turn Ib and delay + rise time (or whatever is appropriate) into an equialent of MOSFET Qg?
Thanks.
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