Hi, i'm writing because i'm building a battery charger PWM controlled by a mcu ATmega8535. Now the issue is that having done the circuit with a step down design to charge the battery, i expect to have a constant current of 600mA, but it rises soon to 200 mA and then rises slowly to 300 mA, on the other hand on the battery cell terminals i can measure 5,7 V and it is dangerous because LI-Ion maximum voltage is 4.2V. I think the software is good, because it's trying to increment the duty cycle of the step down and then the voltage on the battery until a current of 600mA flows across it, but this current threshold cannot be acheived. I post here a schematic of the circuit. Could anyone help me please?
Thank you in advance
Thank you in advance
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