Design help: L200 charger with status LED

[Zeta Phoenix]

I am attempting to design a single cell charger that has status led based on the L200 chip. Does anyone know of a SIMPLE circuit that can be added that would not cause to much drop (I was idealy hoping to power off a 5v brick, but that my leave enough drop for the v-reg)? This was going to be for a 1s 500ma charger. I have attached one I am considering, but I consider it complicated. Would I need a different voltage zener for a 1s charger?

-Jon

[Zlatko]

Hi ZP,

I can't help you with your question, but have you had a look at this topic?

http://www.rcgroups.com/forums/showthread.php?t=793441

Cheers

[Dan Baldwin]

The L200 would not work to charge a single cell Lipo from 5 volts because of the dropout. The L200 has typical 2 volts drop out plus .45 volts across the current sense resistor plus about .7 volts across the 1N4001 in the schematic you posted for a total of about 3.15 volts, which means that you would need a minimum of 7.35 volts input to the circuit.

Dan

[Zeta Phoenix]

Hi ZP,

I can't help you with your question, but have you had a look at this topic?

http://www.rcgroups.com/forums/showthread.php?t=793441

Cheers

Thanks! I had not looked at Microchips line of lipo charging chips (built one around MAX1811, but was getting to hot for my taste).

The L200 would not work to charge a single cell Lipo from 5 volts because of the dropout. The L200 has typical 2 volts drop out plus .45 volts across the current sense resistor plus about .7 volts across the 1N4001 in the schematic you posted for a total of about 3.15 volts, which means that you would need a minimum of 7.35 volts input to the circuit.

Dan
I realized that once I ordered the chips, but this will work off a 12 supply, with lots of heat dissipation.

-Jon