I am trying to command the charging of a battery using a microcontroller and I use a P-type Power Mosfet to discontinue the charging supply after the battery has reached a certain voltage.
I use a N-mosfet (Q2 - SI1012x) to drive the power mosfet (Q1) and the uController commands the N-mosfet (see the picture attached). The R2 resistor keeps the battery charging even if the uController loses power.
The design is pretty straight forward and from my limeted experience should work. However when the Q2 is opened the voltage across R1 is about 2.4 V and that is not enough to close Q1 and disconnect the battery.
I tried changing R1 with no efect (from 50 ohms to 100k). I also removed Q1 and inspected the board for any shortcircuit but I haven't been able to find an explanation for the problem.
In my project the load is connected to the battery and I plan on using a similar design to disconect the load from the battery.
PS: probably I should add a diode to block reverse current, but that is secondary at this moment.
I use a N-mosfet (Q2 - SI1012x) to drive the power mosfet (Q1) and the uController commands the N-mosfet (see the picture attached). The R2 resistor keeps the battery charging even if the uController loses power.
The design is pretty straight forward and from my limeted experience should work. However when the Q2 is opened the voltage across R1 is about 2.4 V and that is not enough to close Q1 and disconnect the battery.
I tried changing R1 with no efect (from 50 ohms to 100k). I also removed Q1 and inspected the board for any shortcircuit but I haven't been able to find an explanation for the problem.
In my project the load is connected to the battery and I plan on using a similar design to disconect the load from the battery.
PS: probably I should add a diode to block reverse current, but that is secondary at this moment.
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