Hello!
I have built a charging circuit for a battery. I used a P-channel Mosfet for a hi side switching needed for the charging. However, I was only able to find a P-Channel Mosfet with full conduction at 10V and my input is only 5V (from uC). Thus, the charging current drew from the power supply is very small.
Finding a logic level P-Channel Mosfet seems hard that's why I tried to use a PNP BJT (TIP32). Turns out that it indeed drew a lot of current from the power supply which is limited to an output of 3A only. However, it turns out that the TIP32 and TIP31(hotter) gets hot fast and while monitoring the battery charge, it seems that it even discharge a little.
I don't know what is the problem but I'm guessing it is due to the resistors, maybe I'm missing some at some point but I don't know where.
here is the schematic:
C1 - simulation only for the charging of the battery (the battery usually have an initial voltage of ~3.5V)
Battery - the supply for charging the battery
input from R9 is from a uC
I have built a charging circuit for a battery. I used a P-channel Mosfet for a hi side switching needed for the charging. However, I was only able to find a P-Channel Mosfet with full conduction at 10V and my input is only 5V (from uC). Thus, the charging current drew from the power supply is very small.
Finding a logic level P-Channel Mosfet seems hard that's why I tried to use a PNP BJT (TIP32). Turns out that it indeed drew a lot of current from the power supply which is limited to an output of 3A only. However, it turns out that the TIP32 and TIP31(hotter) gets hot fast and while monitoring the battery charge, it seems that it even discharge a little.
I don't know what is the problem but I'm guessing it is due to the resistors, maybe I'm missing some at some point but I don't know where.
here is the schematic:
C1 - simulation only for the charging of the battery (the battery usually have an initial voltage of ~3.5V)
Battery - the supply for charging the battery
input from R9 is from a uC