I designed a Low Voltage Disconnect for a 3 Cell Li-Ion Battery pack. Nominal voltage being 10.8V. I set the LVD to turn off the output at 9V. The charger used for this battery pack will not recharge a battery if the voltage is below 7.5V. If the battery is left on the shelf for a period of time I want to have a couple volts available to power the LVD circuit.
The battery back powers a device with a motor and embedded microcontroller. I need to implement some type of hysteresis and if controlling the output with a P Channel MOSFET it would be rather easy as I can just put a resister between the common rail and the voltage reference and then add a feedback resistor to the cathode of voltage reference and the output of the op-amp. When the output is off it would add a few millivolts to the reference point and then lower the reference voltage when the LVD is on.
The circuit I have shown below might work for my application but I am having trouble picking the correct values for R5 or R6. I am not sure if this is the best way of having a circuit that turns on at 10.8V and above while turning off when the voltage is at 9V
Any recommendations for circuit modifications or possibly a formula to calculate the proper resistor values to make this work as intended?
The battery back powers a device with a motor and embedded microcontroller. I need to implement some type of hysteresis and if controlling the output with a P Channel MOSFET it would be rather easy as I can just put a resister between the common rail and the voltage reference and then add a feedback resistor to the cathode of voltage reference and the output of the op-amp. When the output is off it would add a few millivolts to the reference point and then lower the reference voltage when the LVD is on.
The circuit I have shown below might work for my application but I am having trouble picking the correct values for R5 or R6. I am not sure if this is the best way of having a circuit that turns on at 10.8V and above while turning off when the voltage is at 9V
Any recommendations for circuit modifications or possibly a formula to calculate the proper resistor values to make this work as intended?