Hi Joe,
I've got two cell phone chargers to disassemble. One is a Verizon, the other a no-name from Ebay. I'll see if I can get around to do it today and post some pics.

I suspect little differences, but we'll see.

Sherwood

Okay. Finally got around to it. Here are the two cell phone chargers; a Verizon-branded charger and a no-name from Ebay.

http://forums.pelicanparts.com/uploa...1169699290.jpg

Verizon brand charger (about $30):
http://forums.pelicanparts.com/uploa...1169699310.jpg
No name ($10.95 online, about half on Ebay):
http://forums.pelicanparts.com/uploa...1169699325.jpg
http://forums.pelicanparts.com/uploa...1169700114.jpg

They both use the same IC and the components are basically the same. The Verizon plastic case is more substantial and its PC board is larger and components are more separated. The fuse in the Verizon is hard-wired whereas it's replaceable in the other. The prongs for the cig. lighter ground connection looks to be more robust in the Verizon brand.

What tests are needed to determine if one is truly superior over the other? Comments and opinions are welcome.

Sherwood

Guessing at what the extra components do....

It looks like the Verizon one is higher power based on the external drive transistor (> 1 amp ?).

Are the output filter components the same size? (inductor and capacitor)

It also looks like it has more protection components added. Guessing those are input reversal protection diode and a suppression diode at the drive. Could make it last longer.

Also look at the general layout and assembly.

Is the Verizon one worth 3X as much ???? Hmmmm

I woud guess it switches at around 25kHz so it would be hard to see the (full load) ripple without a scope

Switch mode regulator data sheet

A brief status report:

The Verizon charger has an output voltage of around 4.28 VDC.; 20Ma when connected to my prototype circuit.

The Dynamic-brand charger has a an output voltage of around 5.25 VDC.; 35Ma when connected to the same circuit (normal current increase with increased voltage).

Internet sleuthing reports the high voltage charger will charge the cell phone battery in less time but will reduce battery life. Conversely, a lower charging rate (Verizon) will take longer to charge a battery but battery life will increase. Makes sense.

That's the difference between the two chargers I tested. YMMV. However, either of these two chargers suffice for my test circuit.

Sherwood