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asking for suitable driving IC

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afesheir

New Member
hi everybody ..

I have an OpAmp that has an output voltage of about 24 volt. well, this output is going to drive a motor of high current (about 1.5A with starting current of 5 A) ..

by reading the datasheet of uA741, I found that the max. o/p current is 40mA ..

Is there a suitable IC (and available commercially) that can drive this huge motor and delived the required 5A with the 24V from OpAmp ..??

thx in advance ..:D:D
 

Sceadwian

Banned
Isn't the maximum voltage for a uA741 only 22 volts, also it's not a rail to rail opamp so even if run at 24 volts (higher than it's supposed to) it can't provide 24 volts output.
 

afesheir

New Member
yeah it is 22 volt .. sorry i missed this .. ok no problem this can be solved easily i can reduce o/p voltage (over reducing motor speed) but the o/p current problem has to be solved .. so i am still asking for the driving IC ..

thx Sceadwian
 

audioguru

Well-Known Member
Most Helpful Member
Most opamps including the lousy old 741 opamp have a max allowed supply of 36V.

But if you use a high power amplifier then when the voltage to the motor is 18V the heating in the amplifier is the same as the heating in the motor. 18V x 2.5A= 45W which is a lot of heat for an amplifier.
That is why Pulse-Width-Modulation is used to vary the speed of powerful motors on wheelchairs and golf carts so that the electronics stays cool.
 

Sceadwian

Banned
A mosfet as a voltage follower. You'll have to deal with the fact that at low voltages the mosfet will be burning a lot of power though, especially if the motor is stalled.

What's your electronics background because doing something like this is something they cover in school.
 

afesheir

New Member
You don't feed a motor from an opamp, you need considerable power - and if you're trying to vary the speed you use PWM, not a linear device.
ok i will search for speed control using PWM .. thanks alot ..

ost opamps including the lousy old 741 opamp have a max allowed supply of 36V.

But if you use a high power amplifier then when the voltage to the motor is 18V the heating in the amplifier is the same as the heating in the motor. 18V x 2.5A= 45W which is a lot of heat for an amplifier.
That is why Pulse-Width-Modulation is used to vary the speed of powerful motors on wheelchairs and golf carts so that the electronics stays cool.
yeah i got the idea .. thanks alot man ..

What's your electronics background because doing something like this is something they cover in school.
oh by the way .. if u don't like to reply or answer my questions it is up to u, but if u did u shouldn't underestimate forum members in this manner !! did u understand ..?or they don't teach how to speak politely with people in ur school ..?
 

Sceadwian

Banned
afesheir, I was asking what your background in electronics was, the fact that you took that personally is your own problem, leave it out of the forum, ***** at me in private mesages if you want. It was a very valid question.
 
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afesheir

New Member
I understood the question as underestimating me (they cover in schools) but anyway if u don't mean this, forget what i said and forgive my aggressive accent ..

for my background .. I am studying electronics in my faculty but my most interrest is in computer network and communications so I have some poor knowledge of electronics and that is why I participate in this board ..

thx mate ..
 
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