Voltage regulator · AditNow Community

gNick
50.2% (Neutral)
Newbie Topic Starter

12 years ago

Having just bought one of MrMike's very nice Oldham replacement LED boards, I was happily designing myself a battery box for a 3.7V lithium battery when a thought struck me. Once I had recovered from the shock, I thought that instead of building a new voltage battery, why don't I use a nice efficient voltage regulator so I can use one of the several 7.4V batteries that I already have.
Do any of you electronically minded people out there have any useful info to help me here? I did build one in a previous life but I suspect things have moved on a tad since!

Don't look so embarrassed, it's a family trait...

NewStuff
50.2% (Neutral)
Newbie

12 years ago

#2

IIRC, Mr Mikes units have a max Vcc of 6v. Maybe use DC-DC step-down instead of a regulator? A Beefier version of an LT1173 perhaps?

Mr Mike will know far better than I would.

Searching for the ever elusive Underground Titty Bar.

DDDWH CC

Strangely Brown
50.2% (Neutral)
Newbie

12 years ago

#3

Try this as a simple solution, think this chip has a very low voltage dropout.

http://www.ebay.co.uk/itm/LM2596-Voltage-Regulator-board-4-5V-to-40V-in-1-2V-to-37V-out-UK-STOCK-/190814696793?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2c6d713559

Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.

Mr Mike
50.2% (Neutral)
Newbie

12 years ago

#4

"Strangely Brown" wrote:
Try this as a simple solution, think this chip has a very low voltage dropout.

http://www.ebay.co.uk/itm/LM2596-Voltage-Regulator-board-4-5V-to-40V-in-1-2V-to-37V-out-UK-STOCK-/190814696793?pt=UK_BOI_Electrical_Components_Supplies_ET&var=&hash=item2c6d713559

That would work, but it would add considerable size to your battery pack. Also it has protection diodes in, so you would loose 0.25-0.5W in power depending on type, unless you could bypass them.

You would want to set it to 5.0-5.5V output.

I would check for others that might be smaller.

Mr Mike www.mineexplorer.org.uk

Strangely Brown
50.2% (Neutral)
Newbie

12 years ago

#5

Either bypass the diodes and make sure you can only connect the batteries with correct polarity or you can use a P channel MOSFET as a diode which is far more efficient (Mr Fellows takes the credit for telling me this one).

Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.

Mr Mike
50.2% (Neutral)
Newbie

12 years ago

#6

"Strangely Brown" wrote:
(Mr Fellows takes the credit for telling me this one).

I take the credit for telling Mr Fellows.

Some other more compact options:

http://uk.farnell.com/murata-power-solutions/oki-78sr-5-1-5-w36-c/dc-dc-converter-7-5w-single-o-p/dp/2102101

http://uk.farnell.com/xp-power/sr10s05/switching-regulator-5v-1a-o-p/dp/1861095

The second one should do it. The retro XP consumes a max of 0.630A @ 5V input at full power. Size 11.7 x 9.7 x 7.5mm

Mr Mike www.mineexplorer.org.uk

gNick
50.2% (Neutral)
Newbie Topic Starter

12 years ago

#7

I thought you'd have the answer Mike, I just haven't got round to emailing direct! :flowers:

Don't look so embarrassed, it's a family trait...

royfellows
50.2% (Neutral)
Newbie

12 years ago

#8

"Mr Mike" wrote:

"Strangely Brown" wrote:
(Mr Fellows takes the credit for telling me this one).

I take the credit for telling Mr Fellows.

Yes and Mike was so kind as to post schematic for it as well
Its Roy by the way to everyone

My avatar is a poor likeness.

ebgb
50.2% (Neutral)
Newbie

12 years ago

#9

could you not just use a simple LM 7805 ?? cheap as chips (!), constant 5v out, no additional components etc

http://bf494.co.uk

Mr Mike
50.2% (Neutral)
Newbie

12 years ago

#10

It would dissipate too much heat = waste of power, and be bulky with heatsink.

Wrong application of a 7805, also the lower input end of the battery pack would be below its regulation limit. You could use a low drop out version, but it still would have the same issues.

Mr Mike www.mineexplorer.org.uk

Strangely Brown
50.2% (Neutral)
Newbie

12 years ago

#11

Yes, Roy in future.

These USB inverters are handy.

http://www.ebay.co.uk/itm/290628660017?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

I've used the circuits inside for a couple of projects and they do kick out 5V 3A (though the 3A is a bit borderline) Can't remember if they had a protection diode or not (may not even have needed one) and think the drop out was less than 1 volt. I've got one here somewhere, if it turns up I'll do some tests and let you know, it was also easy to tweak the voltage by changing a couple of resistors. Get rid of the casing and remove the USB socket and they are quite small and compact.

Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it.

gNick
50.2% (Neutral)
Newbie Topic Starter

12 years ago

#12

"Mr Mike" wrote:

Some other more compact options:

http://uk.farnell.com/murata-power-solutions/oki-78sr-5-1-5-w36-c/dc-dc-converter-7-5w-single-o-p/dp/2102101

http://uk.farnell.com/xp-power/sr10s05/switching-regulator-5v-1a-o-p/dp/1861095

The second one should do it. The retro XP consumes a max of 0.630A @ 5V input at full power. Size 11.7 x 9.7 x 7.5mm

The second one does indeed do it - taken its time due to being out of stock and then me being otherwise occupied.
Fits neatly in the light housing, in my case stuck the back of MrMike's board with some VHB tape.

Don't look so embarrassed, it's a family trait...