- Tue Nov 30, 2010 10:31 pm
#114587
First here's my schematic:
Its a max1555 powered from usb with the Li-Po battery connected to a two stage regulator. First an mc34063 to boost it to 5v and then a 3.3v linear reg (not a LDO).
The battery is: http://www.sparkfun.com/products/339
The problem is I don't think the battery is charging properly. Unloaded I measure 4.18v. As soon as I switched the power on it drops down to about 900 mV and drops after that by about 50 mV per second and my circuit is only pulling less than 100 mA. After I built the circuit I plugged it in to charge and the 'chg' led indicator turned on. About an hour later it turned off but the battery obviously cannot be fully charged.
If I power my circuit on while the charger is plugged in then the battery drops to about 1.1v and then keeps dropping by 50 mV per second from there.
Ive checked pretty extensively for shorts and found nothing.
Since the indicator isnt on there really isnt a way for me to tell if my battery is getting charged at all...
Anyone help is much appreciated
Its a max1555 powered from usb with the Li-Po battery connected to a two stage regulator. First an mc34063 to boost it to 5v and then a 3.3v linear reg (not a LDO).
The battery is: http://www.sparkfun.com/products/339
The problem is I don't think the battery is charging properly. Unloaded I measure 4.18v. As soon as I switched the power on it drops down to about 900 mV and drops after that by about 50 mV per second and my circuit is only pulling less than 100 mA. After I built the circuit I plugged it in to charge and the 'chg' led indicator turned on. About an hour later it turned off but the battery obviously cannot be fully charged.
If I power my circuit on while the charger is plugged in then the battery drops to about 1.1v and then keeps dropping by 50 mV per second from there.
Ive checked pretty extensively for shorts and found nothing.
Since the indicator isnt on there really isnt a way for me to tell if my battery is getting charged at all...
Anyone help is much appreciated