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# BLDC,3 half H Bridge, help to choose driver

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#### SuperTrump

##### Junior Member level 1
Hi there!

I'm building an e-bike for my bachelor thesis, and i have a problem with driving the bldc motor.
The motor is at 250W and my battery at 24V. I will drive the motor with a 3 half H bridge and lets assume that i decided to use the IRFB4110PbF mosfet (if u have to recommend a better one, please do!). Here comes my problem, which is lack of knowledge .
This mosfet, has input capacitance Ciss = 9620pf. So i found an article talking about input impedance and input capacitance and if i understood well, i need a Ig to drive the mosfet quick enough to the ON state. So my calculation are:

If i want to have Vgs = 10V
Ig=I1+I2 where
I1= C1xdV /dt = Ciss x 10V / tr = 1,435 mA
I2= C2 (Vdc+10V) / dt = Crss x 34V / tr = 0,126 A
so
Ig = 1,561A

First of all, this is how we determine the required Ig ??
And my main question, all i need is a driver that will have a 5V input (from a micro controller) and will have an output of 10V and 1.5A ??

I hope that i 'm not totally out of my way...

Dimitris

Anyone?? :|

chitru

Points: 2