Overcharge/discharge cutoff for 1 watt LED circuit using a MC34161

Thread Starter


Joined Feb 7, 2012
Hello everyone,
I need help calculating the proper resistor values for a dual comparator input MC34161 to be used in a 1 Watt LED light circuit that will be powered by four AA 1.2v 2500 mah batteries in series. The 1 watt LED draws 350ma @ 3-3.6v but I would like to operate it at around 150 ma to obtain an approximate 10 hour run time on the battery pack. I realize the output of the IC is 10ma max so I would need a transistor or FET in the circuit as well along with values.

From what I've read the batteries shouldn't be charged over 1.43v per cell. They shouldn't be discharged lower than 1.1v per cell especially when using unbalanced cells in a pack such as this. This is why I want to use this particular IC so it can shutdown on an overcharge or discharge condition.

Any help would be appreciated.