i want your ideas to do a circuit that amplify input signal 0-10 V to 5-24 v to control a 24 v proportional dc valve

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What current is the valve coil?
Max.

 

1.5 Amp is the max.

 

I would look at using something like the OPA551, it is good for ±30v swing at 300ma so you would need a NPN/PNP push-pull output to drive the valve.
Max.

 

Or you can use one of the high-current opamps from here.

 

Or you can use one of the high-current opamps from here.

oh GOD up to 50A it must be very expensive type of opamp.

 

but why should i use this type of opamp? why couldn't use it to drive mosfet that could hold high current instead of opamp?

 

but why should i use this type of opamp? why couldn't use it to drive mosfet that could hold high current instead of opamp?

You didn't look far enough down the page. Apex sells some 3A ones.

In a previous life, I bought hundreds of that type of opamp from Apex.

 

excuse me ,

You didn't look far enough down the page. Apex sells some 3A ones.

In a previous life, I bought hundreds of that type of opamp from Apex.

excuse me,i don't get you

 

...i don't get you

Look up PA74, PA74A, PA75, or PA76 on the Apex web site.

 

oh GOD up to 50A it must be very expensive type of opamp.

TI will send you a couple free samples of OPA551!
Max.

 

ok ,i got you it's dual channel . what is the relation between that and my question?
PA76A costs 131 USD , however there is a Chinese proportional card costs just around 125$ http://www.hawe.de/en/products/product/product/ev-amplifiers-for-proportional-solenoids/

 

I would look at using something like the OPA551, it is good for ±30v swing at 300ma so you would need a NPN/PNP push-pull output to drive the valve.
Max.

but the npn /pnp can't drive 1 A to the valve.

 

but the npn /pnp can't drive 1 A to the valve.

I meant a couple of discrete bi-polar devices to increase the output capacity.
Max.

 

what do you mean by a couple? how to do it ? would you clarify with a picture?

 

Like so.


Max.

 

The normal way of controlling this kind of valve is to drive it with a current that is proportional to the input control voltage, not a voltage proportional to the input.

 

Like so.
View attachment 77801

Max.

this will operate as a voltage follower. when there is positve output the npn will work and connects +v to the valve then 1A passed and blow up the npn

 

The normal way of controlling this kind of valve is to drive it with a current that is proportional to the input control voltage, not a voltage proportional to the input.

That is basically the method I used in #16, in CNC applications where ±10vdc analogue is the source.
Feedback via encoder.

this will operate as a voltage follower. when there is positve output the npn will work and connects +v to the valve then 1A passed and blow up the npn

The circuit shown has been around for a long time used in EDM machines etc.
You can limit the maximum freq by resistor in the collectors if needed, or on the output.
Max.

 

The normal way of controlling this kind of valve is to drive it with a current that is proportional to the input control voltage, not a voltage proportional to the input.

did you see the operation in the link ? i want to do something like this.i don't mind to do it with current but also the valve shouldn't mind