Power Supply/Battery Charger/CC Supply All In One

Hello,

Here's a pretty simple power supply that can also charge
batteries and work as a constant current source for many
of your testing needs. Depending on what resistors you
connect to the terminal strip, you either get a
1. Voltage regulator
2. Current regulator
3. Li-ion battery charger (up to 1.5 amps)
4. NiMH batt charger (if you're willing to watch for -dV)

This could have been called
"Power Supply on a Terminal Strip"

With the terminals strip, you can connect any kind of
resistors you need to configure the ps any way you need.

To run as voltage regulator alone, connect
Rvs, RCL, and 220 ohm resistor. RCL sets current limit.

To run as constant current supply, short RCL and connect
RCC and dont connect Rvs.
This will also charge NiMH cells if you watch for
the minus delta V with a meter.

To charge Li-ion cell, use Rvs, RCL, and 220 resistor.
Set Vout with pot to 4.15 volts, then connect cell.
RCL limits max current for your cell, depending on
what kind of cell it is.

Heat sink should be large enough so the LM317 doesnt
go into thermal overload with high input voltage
and low output voltage and high current.
I used a heat sink with many fins, size 3x3x1.5 inches.

I actually built and tested this with the terminal
strip, and i can tell you it's the most versatile
power supply i've ever had.
The terminal strip i used only had one screw per position,
but you can get the type with two screws per position to
set this up without having to solder anything to the
terminal strip.
I used a 10 turn pot but you can use almost anything
from about 1k to 5k. The 1k 10turn pot gives nicer
voltage adjustment.





Take care,
Al

love the wiring on a terminal strip that's genius.

Its a Great Design Mr Al,

Thanks for keeping it Soooo simple.

I will be building this along with the charger (other Post) based on same LM317 ...

Today, Its sunday, so shops closed here... i will be getting the parts tomorow....

Also, I doubt if i could get a 10 turn 1 K pot.... but i can surely get 10 100 ohms pot..... it will make my power supply box "more Scientific" if others see me working with this so many of em.. adjusting "EACH" of em to get a "PERFECT" voltage .... hehehehe... but my question is that .. will that serve my purpose ? i mean using 10 pots of 100 each achieving the more precise change in voltage...

Thanks & Regards,
ViReN

Hi again,

andrew:
Ok, i had my laugh for the day /ubbthreads/images/graemlins/smile.gif
The terminal strip i used has solder lugs on the bottom
so you have to solder the permanent wires to the bottom,
but i think it would be easier with a double screw type.
It works pretty nice however, because you can stick any
resistor you want on it to program output current max
and constant current, and to set the max output
voltage.
At some point i'll probably solder the 220 ohm resistor
into the circuit, because all applications required
that the regulator chip draw at least 5ma, so that
resistor can always be present for any configuration. If
in constant current mode, it only adds another 5.5ma
to the total cc output, and i intend to use this mostly
from 100ma up to maybe 1.2 amps.
I guess it should be noted that the 220 ohm resistor is
about the maximum value for use when using for voltage
regulation, but if using another chip (like LM350)
you'll have to check the min current requirement for
that new chip. It may have to be as low as 100 for some
chips.

Viren:
You can save yourself some trouble by using a 1k pot in
series with a 100 ohm pot instead of 10 x 100 ohm pots /ubbthreads/images/graemlins/smile.gif
You set the approx output with the 1k pot, then adjust
the 100 ohm for fine tuning. You may have to adjust the
100 ohm to one end or in the center before you start.

Take care,
Al

Ah Excellent Idea Mr Al....

Good Morning by the way /ubbthreads/images/graemlins/smile.gif

-ViReN

Hi Viren,

Good morning /ubbthreads/images/graemlins/smile.gif

Take care,
Al

Hello Mr Al,

I had been working on a couple of things .. including crazy ideas (regulated Photon Freedom Light) ... nourishing them ... Here & Here ... Also built up a new MiniM-G Lite Mod any ways...

Back to Power Supply...

Before I actually build (Make using EasyPCB Method) this PCB & solder the things up, i want to ask a few quesitons here.

Please view the images

Pic1 : a typical 78XX Voltage Regulator, 5 times zoomed PCB


Please Note I/P & O/P Capacitors

Pic2 : Adjustable Voltage Regulator using LM317, 5 times zoomed PCB

Please Note Only I/P Capacitor

Now My Question is, We Know that Capacitor gets charged if left on NO-LOAD Condition. So When the I/P Is there and i am yet to connect any thing to the O/P Side, a Brilliant Spark will appear, most likely will also DAMAGE the Circuit that i am testing. so, as an improvement to this, If i Remove the O/P Capacitor, what will be the case? will similar thing happen (knowing that there is an capacitor at I/P End....

I am a TOTAL Newbie in PS, please advice....

Thanks & Regards,
ViReN

Hi Viren,

With the linear supplies you dont have to worry as much
as with the boost supplies. With the boost supplies
operated no-load there could be a problem with the
output cap charging up to high levels, but with the linear
supply that's not going to happen. The load connected
should be able to handle the voltage you adjust the
supply for (before connecting) so it will always be ok.

I use mine without any caps at all and it seems to
work just fine (LM317). If you want to add caps
it wont hurt.
If you're looking for better ripple output, check the
data sheet on the LM317 for tips for adding a cap to
the ADJ pin too.

Take care,
Al