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Topic: Li Ion charger capable of charging incorrectl placed batts (Read 1618 times) previous topic - next topic

Li Ion charger capable of charging incorrectl placed batts

HI I got this cheap universal chareger for a phone that had it's USB jack snapped off and taken the traces with it.. so no cable charging is posible..
http://www.chinabuye.com/3g-usb-portabl ... ry-charger

It's an interesting little device. You set the location and pitch of the little spring loaded pins, and you connect up any Li Ion battery.. and it gets charged... Now the interesting part is that the charger will safly charge batteries no matter how you connected the + and - pins... you can connect + to the left one and the - to the right one, or the other way around and it will work without issues... No third pin means no thermal monitoring, but from what I figured out it charges at only ~300mA, and from the charging tests I made, the batteries bearly got heated at all, far less then when charged through my phone..

I was intrigued so I opened the little thing up to see how it works..

It has the classic simplest and cheapest flyback (optocoupler + zener) controlled 5V regulator.... nothing worth mentioning there.. But the battery is connected to a DIP 8 IC with markings mt1151D.

with pin 1 connected to one of the batttery prongs, and a bypass cap. pin 2 is NC, pin 3 connects to a charging LED.. forgot where pin 4 is connected (probably GND). pin 5 and 6 are GND, pin 7 is connected to the second battery prong, also bypassed to GND, and pin 8 is connected to VCC...

Offcourse searching for this IC online has proven to be impossible, does anyone know of a similar charging chip that can do this as well..
best regards FIlip.

Re: Li Ion charger capable of charging incorrectl placed bat

Reply #1
Ha that's a cool little gadget, unfortunately I don't know of a similar charging chip. I took a look and the stuff on there is pretty cheap though!