UCD 25 watts to 1200 watts using 2 mosfets

Hi All

The importance of the gate charge data to the designer is illustrated
as follows. Taking the charge are required to switch a previous
example, about 15 nanocoulombs of gate if 1.5 amps is supplied to the
gate, the device will be drain voltage of 80 volts and a drain current
of 12 amps. Since the 15 nC gate charge is the product of the gate
input current and the switching time, switched in 10 nS. It follows
that if 15 mA is supplied to the gate, then switching occurs in 1 us,
and so on. These simple calculations immediately tell the designer the
trade-offs between the amount of current available from the drive
circuit and the achievable switching time. With gate charge known,
the designer can develop a drive circuit appropriate to the switching
time required.
Consider a typical practical example of a 100 kHz switcher, in which
it is required to achieve a switching time of 100 nanoseconds.The required gate drive current is derived by simply dividing the gate charge, 15 X 10
-9
, by the required switching time, 100 X
10
-9
, giving 150 mA. From this calculation, the designer can further arrive at the drive circuit impedance. If the drive circuit
applies 14 volts to the gate, for instance, then a drive impedance of about 50 ohms would be required.
Link: http://www.electro-tech-online.com/custompdfs/2010/08/an-944.pdf
Regards
Manoj
 
Hi Manoj
IR2110 can drive 2nos of IRFP250N(Qg=140) 3nos of IRFP240 & IRFP4227 (Qg=70 minimum)

Yes it can , but it'll overheat :flame::D
The DIP package can dissipate more power that the SOIC one
 

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I already posted the graphs from 2110 datasheet
Maybe you missed them?
They are for a IRFPE50 with it' 150 nC total gate charge at 15V at gate.
How you can see the SOIC can heats up to 100 degrees at 300KHz , i think it's too much IMHO:)
Yes , it can sustain more (up to 150Deg) but it's too critical.
 

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Manoj
is it right???
I don't really know:)
We are speaking of two independent things , the capability of driving due-to Qgate vs. Iout (your opinion) and Qgate vs. Temperature IC.
The Appnote that you mentioned is only a guide /theoretical layout how to design the gate drive on an ideal and not on a specific IC.
If you put a good heatsink on IR2110 , a really good one , maybe it'll be "ideal" and your calculations will be right.
Regards
Dmitri