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Gear / Technical Help => Remote Power => Topic started by: gorlando on February 24, 2007, 08:54:26 AM

Title: 5V battery box with a switching regulator
Post by: gorlando on February 24, 2007, 08:54:26 AM
In the search for the "ideal" battery box for my MT 24/06 I incurred in the data sheet of a switching booster regulator, the LM2623 and decided to build it.
The circuit schematic diagram from the data sheet is in the picture attached (the data sheet can be easily downloaded based on a Google search).
The problem with this IC is that it is really minuscole, so I had to make some micro-surgery, the result of which in in the attached photos, not very nice but it works.
I used a coin as a safety measure to improve the IC generated heat dispersion.
This regulator works with a 4 AA NiMH battery pack. I used 2700 mAh batteries. I have tested this device for almost 3 weeks now and it works flawlessly. I made a couple of tests connecting the regulator to a load of 20 Ohms (i.e. 250 mA with 5V) and measuring the outlet voltage and the battery voltage (see attached graphs) vs. time.
The battery pack supply 5V (actually 4.9V, maybe for the tolerances of the resistors which determine the output voltage) for around 8 hours. Then the voltage drops very rapidly, but at this point I have still the MT internal battery full.
I also tested this device in the field and recorded for about 5 hours without any problem. It is important to say that there is no noise in the recording due to possible interference of the high switching frequency of the regulator with the sensible audio circuits of the MT.
It could be of interest to others so I post it.
Giovanni

Title: Re: 5V battery box with a switching regulator
Post by: pigiron on February 25, 2007, 01:02:40 PM
+t on the DIY!

Glad to see that noise isn't a problem.
Title: Re: 5V battery box with a switching regulator
Post by: margilca on May 14, 2007, 04:13:19 AM
Giovanni,
given your name and the coin you glued on your kit, I assume you are based in Italy.
Where did you get LM2623 ? Are other packages available ?
Thanks
Cheers
Margilca
Title: Re: 5V battery box with a switching regulator
Post by: shaggy on May 14, 2007, 07:00:26 AM
What about that Right Angle USB Mini B connector?  Is that home made or store bought?
Title: Re: 5V battery box with a switching regulator
Post by: boojum on May 14, 2007, 12:25:32 PM
Tasty, tasty.  Very nice.  You did good, guy.  Perfecto!    8)
Title: Re: 5V battery box with a switching regulator
Post by: gorlando on May 16, 2007, 12:03:43 AM
I bought the LM2623 from RS Components (http://www.rs-components.com/index.html). You can buy via phone and have the materials sent via courier. I would buy only special components from them, since they are expensive.
I have one of their shop close to my home (Milano - Italy), so normally I go there myself.

The right-angle USB mini B connector is custom made by me. You need to destroy a cable to recover the connector and then, with a bit of patience and some hot glue it is not very difficult to build.

I am very happy of this battery box, which I am using by default, since the internal battery of the MT is unreliable.
The only real challenge id fixing the IC to the DIP socket. It is so small I had to buy a magnifying lens tool (cheap and easy to find in electronic shops) and be very careful in welding the tiny IC terminals to short metal leads and then to the DIP socket. It is not impossible but also here a good dose of patience is needed.
Hope this is of help to somebody
Giovanni