5 volts supply design

Got any questions or comments on any of our other products, such as Mathematics or Geography, then this is to forum for you.

Moderators: Benj, Mods

Post Reply
User avatar
acestu
Posts: 1720
Joined: Thu Dec 01, 2011 9:36 pm
Location: Macclesfield UK
Contact:

5 volts supply design

Post by acestu »

Hi,

I am trying to build a simple power supply for a diy project, it consists of an i2c 4 x 20 display, a pic 16f1824 and a 5 volt songle relay, I have built an LM2567 -5 3amp 5v supply which I can run off a 12 volt battery detailed here:

http://www.ti.com/lit/ds/symlink/lm2576.pdf

and attached it to my breadboard but when I start it up it powers everything but when the relay kicks in the display goes dim, could this be because I am using a breadboard with long loose wires everywhere ? or should I be using a different power supply ? as ever any information is greatly appreciated.

thanks
Stuart
Laptop Mac Book Pro i7 retina El Capitan //// Tower/Intel i7-Windows 7 64 Bit, Toshiba i5 Laptop Windows 10
Computers are like air conditioners. They work fine until you start opening windows.

User avatar
Steve001
Valued Contributor
Valued Contributor
Posts: 1142
Joined: Wed Dec 31, 2008 3:37 pm
Contact:

Re: 5 volts supply design

Post by Steve001 »

Hi Stuart

Personally I wouldn't use 5 volts to power drive a relay coil I would keep coils etc. well away from the 5 volts.
I would use a transistor relay driver from 12 volts supply.

have you seen the layout guides ? these devices are quite finicky they like low impedance supply and ground interconnections.(try doubling up your links and tidying up your wires make as short as possible)

Also I am not sure if the added inductance to ground upsets the regulation with the relay energised.

A relay driver circuit can be found on the relay board eblock

http://www.matrixtsl.com/resources/file ... 8-30-1.pdf

Steve
Success always occurs in private and failure in full view.

User avatar
acestu
Posts: 1720
Joined: Thu Dec 01, 2011 9:36 pm
Location: Macclesfield UK
Contact:

Re: 5 volts supply design

Post by acestu »

Hi Steve,

So what you are saying is use the 5v out from the microcontroller to switch the negative side of a 12 volt circuit switching the relay instead of switching the negative side of a 5 volts switching the relay ?

thanks
Stuart
Laptop Mac Book Pro i7 retina El Capitan //// Tower/Intel i7-Windows 7 64 Bit, Toshiba i5 Laptop Windows 10
Computers are like air conditioners. They work fine until you start opening windows.

User avatar
Steve001
Valued Contributor
Valued Contributor
Posts: 1142
Joined: Wed Dec 31, 2008 3:37 pm
Contact:

Re: 5 volts supply design

Post by Steve001 »

Hi Stuart

you use the output of the micro to drive a transistor this the can be used to switch a higher separate voltage circuit such as the 12 volts to power your relay.

A relay driver example attached along with a micro controller interfacing circuits pdf that i found on here some time ago
(thank you who ever posted this)

Steve
Attachments
example relay driver circuit.JPG
example relay driver circuit.JPG (74.89 KiB) Viewed 5015 times
MICROCONTROLLER interfacing circuits.pdf
(348.32 KiB) Downloaded 119 times
Success always occurs in private and failure in full view.

User avatar
acestu
Posts: 1720
Joined: Thu Dec 01, 2011 9:36 pm
Location: Macclesfield UK
Contact:

Re: 5 volts supply design

Post by acestu »

Hi Steve,

That's brilliant thanks.

Stuart
Laptop Mac Book Pro i7 retina El Capitan //// Tower/Intel i7-Windows 7 64 Bit, Toshiba i5 Laptop Windows 10
Computers are like air conditioners. They work fine until you start opening windows.

Post Reply