Game Gear Internal Battery Charger

@littlefreak3000 got me thinking about replacing the entire power board. Well I designed something up, not sure when I'll get to building it thought.

There is no good way that I could figure out to balance charge lipo/lithium while supply a load simultaneously. I want to be able to charge batteries and play at the same time. So I've come up with something different. Run 6 * 14500 batteries in parallel. These batteries run roughly from 3v to 4.2v. So I need to boost the voltage up to 5v, along with a basic voltage divider of 1.28v for vref. I'll need to change out the voltage divider for VBAT/VONE on the game gear so it doesn't get fussy thinking I'm low on juice. I also need undervolt protection to make sure the power circuit shuts down at 3v.

This is what I've got so far:

 

An idea also is to make the 38V rail optional. I know there are many people like me who have done away with the cold cathode backlight. So you might be able to build it with a jumper or something that you can leave the 38V and the needed components off if you don't need them.

 

Sorry to bump an old thread, but IIRC the power jack on the GG uses closed switches, meaning pluging the jack will unconnect the AAA batteries and power the GG.
Isn't possible to doing something similar? Like plugin the AC adatper swtich the circuit to recharge the batteries AND power the GG (and not let the batteries still powering the GG while being recharged)?

 

My original design does this already. I bypassed the internal switch. My new design, if I ever get to it, does the same thing.

 

Ho ok. I really hope you got your design I'm sure people will be intrested.