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Dc-Dc Buck converter

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i bought alot of IRF9540n ICs :(
i need suitable solutions for my problems

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this is a mistake.
because 99% designes are based on n channel mosfets.
by using gate driver ic you can switch on +ve or -ve supply.
so both problems +ve switching or -ve switching is possible by n channel mosfets.
another thing that there is no verity of p channel mosfets.



mosfets that i have mentioned are not so caustly.
irf740= irf840= 40 rupees= .5$
irf450= 125rupees=1.2$.

have you bought these from hall road???????
 

can you give schematic for using n-channel-mosfet in dc-dc chopper
and in my local stock there is only one gate driver IR2110
 

if work with p-channel and irf2110 driver ... how the driver will adjust Vgs ... it's output is 20 volt max ?? i have 48 volt source
 

driver can not drive p-channel mosfet's.
if you want to use a mosfet as switch . and you want to turn on mosfet then gate need Vgs of approximately 10v .
and when you want to turn off mosfet then gate need Vgs of 0v or -ve voltages if possible.
when you use mosfet as high side switch and turn it on then drain voltages passes through mosfet and goes to source.
now source voltages are equal to vd (drain voltage ). and now gate shuld have Vgs of 10v . so you need Vcc+10 now.
this ic solves this problem by using charg pump technique.
 

irfan ahmad said:
driver can not drive p-channel mosfet's.
if you want to use a mosfet as switch . and you want to turn on mosfet then gate need Vgs of approximately 10v .
and when you want to turn off mosfet then gate need Vgs of 0v or -ve voltages if possible.
when you use mosfet as high side switch and turn it on then drain voltages passes through mosfet and goes to source.
now source voltages are equal to vd (drain voltage ). and now gate shuld have Vgs of 10v . so you need Vcc+10 now.
this ic solves this problem by using charg pump technique.
Click to expand...
you talked about n-mosfet
i have no time to try all these things
i want to drive p-mosfet , can i ? using IR2110 ?
 

Here is a way to drive a P-mosfet, so that it conducts when the control signal is positive.



During On-time, the gate level is pulled close to 0V, which is sufficient to turn it on.

During Off-time, the gate automatically receives 48 V, which is the volt level needed to turn it off.

The additional transistor might cause a small delay in the action. This could make a difference when operating frequency is very fast.
 

BradtheRad said:
Here is a way to drive a P-mosfet, so that it conducts when the control signal is positive.



During On-time, the gate level is pulled close to 0V, which is sufficient to turn it on.

During Off-time, the gate automatically receives 48 V, which is the volt level needed to turn it off.

The additional transistor might cause a small delay in the action. This could make a difference when operating frequency is very fast.
Click to expand...
vgs max = +/- 20 v

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... i will use n-mosfet as many people advised me
so how can i use IR2110 to drive IRF540n (resistors , capacitor)
 

switch.JPG

try this circuit.
 

If you look your other thread, https://www.edaboard.com/threads/279004/, you will find my proposal for gate drive circuitry. It will not over-drive the gate voltage (a zener limits it to 15V) and it has a "speed-up-circuit for discharging the gate.

You may further increase the off->on switching speed by adding a small capacitor (maybe a few hundred pF maximum) parallel with R1 on that schematics.

I copy the schematics also here. The notes I made earlier, that I have not had time to properly calculate component values, still applies. They should be checked. However, this should work as it is, but at least reverse VBE of Q1 should be verified.

The fact, that regulation needs some load applies for the circuitry anyway, so if you put for instance a resistor load on it, things are easier for microcontroller to regulate, And the programming is bit tricky, so you have to understand how your "software-set gain" and processing delays work out as part of a feedback loop.

17545_22.jpg
 

what is rate of power >>> output voltage*current or input voltage*current??
my mosfet IRF9540 is 140 watt max i have 48 volt in 24 volt out
 

what is rate of power >>> output voltage*current or input voltage*current??
Click to expand...

While it is conducting, the mosfet will be like a switch. The goal is to drive it fully on, so it will have minimal resistance. It will show minimal voltage drop.

Then it should be able to carry several amps, yet without dissipating several watts as heat.

It should not heat up much if you stay under its current rating. Nevertheless you should expect to provide heatsinking in case it does start heating up.

To my mind, if it gets so hot it burns my fingers, then it needs heatsinking.
 

ahmedmedowahdan said:
can i replace
ir2101 with ir2110
what is high freq diode
is ther capacitor of .1uf value?
What watt size of resistors?( is there high watt resistors?)
Click to expand...


1 : Yes you can use ir2110.
2 : Fast recovery diode. More examples example fr 207 , fr307
3 : Capacitor shuld 1uf .
4 : Resistor shuld 2/w minimum.
 

irfan ahmad said:
1 : Yes you can use ir2110.
2 : Fast recovery diode. More examples example fr 207 , fr307
3 : Capacitor shuld 1uf .
4 : Resistor shuld 2/w minimum.
Click to expand...
capacitor you mean is bootstrap cap ?
resistor of 2W or 1/2 w??
 

Two watt resistor.
Yes this is bootstrap capacitor . Which is boosting gate voltages for high side mosfet.
 

**broken link removed**
what vlaue of RG
Zener diode D3 and R1
i found this paper , it's notes for IR2110 form IR
 

what i different between Vcc & VDD & Vb and what i have to connect for high side >
 

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