View Full Version : Singray with LiPo, undervoltage protection

10-29-2011, 08:58 AM
I wanted to feed my stingray platform from a 7,4V 5000mAh Lipo, but I was alays concerned about deep discharging the battery,
So I made a little UVP circuit with a Texas TL7705 (not the CMOS TLC7705!). I build it on a veroboard using ISIS and VeeCad.
Schematic & pics attached.
BTW the circuit starts only after attaching the battery and pushing the "ON" button. The circuit switches off either when the "OFF"
button is pressed or when the input voltage drops below 6V. It will not restart automatically when the battery delivers more voltage
because of the load is disconnected, the "ON" button must be pressed again. The treshold can be adjusted with R9/R10, up to about
16V. 18V is the max Vcc for the TL7705. In the off state the UVP takes only about 2 mA.