Hi myasir786, Can you tell me about your battery? What kind of battery are you trying to charge? Charging lithium ion battery is different for nickel metal hydrid (NiMH) battery, different from nickel cadmium (NiCd) battery, different from lead-acid battery.
How many cells are trying to charge? This will determine your minimum source voltage.
Do you need fast charger (1-3 hours) or slow charge (~24 hours)?
Slow charger or trickle charge is easier to implement. For NiCd or NiMH battery, you only need a current source to charge a battery at about 0.05C (5% of the capacity, i.e. 50mA for a 1000mAh battery). Sometime people just use a resistor to limit the current to 0.05C is sufficient.
For fast charge, it is more complex. You need to detect and terminate charging. People generally use monolithic IC for fast charge.
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