I have a power managent IC that has features of Under and Over Voltage Protection through the EN and OVP pins. These pins are enabled by manipulating the voltages on the pin via a 3-resistor voltage divider.
Now my circuit takes in two configurations for the Li-ion battery for power, either at 3.7 volts (using 1 18650) or at 7.4 volts (using 2 18350). This makes it tricky for the power management IC. It is possible to use two of the PMIC for the different configuration making sure that only one is always active. But it take a lot more components and not much more GPIO pins for monitoring.
I was wondering if there is any way to switch between two different voltage dividers depending on the input voltage. Without using timers, I do not want to keep adjusting it.
The input voltage share the same line, but if the voltage is let's say lower than 5V, it will use the voltage divider on the left and if it's higher than 6V it will use the divider on the right.
Best Answer
You could use a 4053 multiplexer with a comparator and voltage reference for selecting. Be sure to carefully analyze this idea to see if it makes sense in all possible situations. The reference has to work from the lowest possible voltage with one cell, so you'll have to divide the battery voltage down.
A better solution might be to add a couple of jumper blocks or a DIP switch to change from 1 to two cells. You could use a single chain of 5 resistors.