Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Common Ground Problem

Status
Not open for further replies.

Nihan

New Member
Hello

I work on a converter circuit which works with 24V AC or DC input. And since I need common ground I used half wave rectifier. But the problem is since half rectified voltage is half effective than full rectified, I can not supply enough current to my circuit.

Here is my circuit

MC34063.PNG


So I thought I should use bridge rectifier but if I use it how can I provide common ground?
I don't think it is right thing to do but if I connect the red wire is it possible?

Capture.PNG
 

MaxHeadRoom78

Well-Known Member
Most Helpful Member
You cannot have two power commons at the same potential either side of a bridge rectifier.
One or the other.
Also AC24vac will not be a N if it is not at earth ground or a star point of a 3ph transformer..
Max.
 

spectrum

Member
As far as i know, your first diagram seems good for powering 24VAC and DC.
You said you cannot supply enough current. In place of EC50 i would use a 2200 u and things should work. I am more a fw developer btw, so let's wait confirmation from better masters.
 
Last edited:

dr pepper

Well-Known Member
Most Helpful Member
Initially I'd be trying a larger cap in C51's position, and one that has a low esr, it sounds like the voltage on this cap is dipping low enough for the '34063 not to regulate properly.
Ideally you'd want to calc the value, there are implications on other aspects of the circuit such as inrush, so you might need to beef up the 1n4007 and increase the fuse if your able to do so.
Its also going to affect stability & your compensation network being a voltage control switcher, can you rerrange the power supply to maybe + - 12v ac.
 

unclejed613

Well-Known Member
Most Helpful Member
make the fuse a time-delay (indicated by a "T" designation rather than a "F" for fast-blow) to deal with the inrush current charging the larger capacitor and use a 3A diode.
 

MaxHeadRoom78

Well-Known Member
Most Helpful Member
Does the circuits need to be referenced to earth ground as your symbol implies?
Max.
 

Attachments

  • GNDsymb copy.jpg
    GNDsymb copy.jpg
    23.3 KB · Views: 15
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top