LM2576: LM2576

Ramana Murthy

Part Number: LM2576
Other Parts Discussed in Thread: LM317

Dear Sir,

i want to give feedback voltage to pin No:4 through an voltage buffer from externally controller instead of voltage divider.i want to generate 2 Volt to 12 Volt variable voltage at output with 24 Volt input supply by using feedback pin no:4 i want to vary output voltage.my aim is that i don;t want to use potentiometer to vary the output voltage.

over 6 years ago

0 kai klaas69 over 6 years ago

Guru 140200 points

Hi Anand,

and your question is?

Kai

0 Ramana Murthy over 6 years ago in reply to kai klaas69

Expert 1765 points

Dear Sir,
i am using LM2576 HVS-ADJ
i want to control the output voltage by external Voltage not by using potentiometer.

Input is 60 V
output is Required 0 to 36 VDC'
Current : 100mA

i want to give control voltage externally to control the output voltage
please suggest IC suitable for this application

0 Samuel Jaffe over 6 years ago in reply to Ramana Murthy

TI__Mastermind 25590 points

Anand Murthy,

This depends on what is controlling this voltage. Do you have a microcontroller which will control the voltage of LM2576? If so you could use a DAC or PWM with some filtering. If not, what is controlling this voltage?

-Sam

0 Ramana Murthy over 6 years ago in reply to Samuel Jaffe

Expert 1765 points

Yes Sam,I am using Microcontroller which is generating control voltage using DAC.

0 kai klaas69 over 6 years ago in reply to Ramana Murthy

Guru 140200 points

Hi Anand,

you could use the methode shown in this post:

e2e.ti.com/.../304938

Here a negative regulator is shown, though. But the principle is the same. You see that the LM2576 still has a voltage divider to provide the needed feedback loop. Without that feedback loop the LM2576 will not operate properly. Keep in mind that the LM2576 does not work like a LM317 where a different scheme can be used.

Then you add a resitstance to the feedback pin of LM2576 and impress a control current to change the output voltage of LM2576.

Kai

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LM2576: LM2576