help schematic.. pic mcu pwm out controlling LM2576 or LM2596 0-25VDC

[mbyka]

i need simple but stabil adjustable DC 0-25v 3A or 5A support supply schematic for my 24v dc motor.
i dont want to use for control the motor with any buck boost converter becaouse motor cable wil be long(3meter) to control board.
For that reason i want to control my dc motor voltage range 0-25 dc with out voltage of lm2576 it has suport 3A or lm2596 has support 5A(it is better)
i want to use picf16877 pwm out to change regulator out voltage
but my analog electronic level is not enough to modify lm2576/lm2596 with my own self op-amp knowlege
so why i want help from you.
thank you .

 

[schmitt trigger]

For starters: What is the DC input voltage range?

Most modern micros are capable enough to implement a switchmode topology without requiring a LM2576. But you will definitively require an external Power fet, a fet driver IC, and external current sensing.

 

[mbyka]

input voltage wil be 24v dc or 30vdc by other lm2596 circuit(on market)
i will control 3 motor(selectable) with only one pwm outand one adjustable lm2596 voltage source
3 motor will never run in same time together.

 

[KlausST]

Hi,

I don't understand your requirements.
I read you don't want to use a buck converter, but LM2576 is a buck converter.
And I don't understand what cable length has to do...

Please draw a sketch of what you need.

Klaus

 

[mbyka]

i dont want to make my own a buck converter with external mosfet ,inductor and control current and voltage with pic mcu

 

[KlausST]

Hi,

In another post you referred to this: https://www.edaboard.com/showthread.php?377215-Design-of-PWM-controlled-SMPS-output-voltage
As far as I can see this is exactly what you need. What's the problem with it?

Klaus