LTC4012 battery schematic charger

This battery charger circuit diagram is a very simple high efficiency switchmode battery charger circuit based on the LTC4012 IC , manufactured by Linear Technology Corporation .
This charger support supports Li-Ion/Polymer, NiMH, NiCd and sealed lead acid battery chemistries in single and multicell configurations.
When the LTC4012-3 is charging, the voltage on the PROG
pin varies in direct proportion to the charge current. The nominal PROG voltage is given by: VPROG=(ICHRG x RSENSE x RPROG/RIN) +11.67uAxRPROG
The formula for charge current is: ICHRG=(RIN/RSENSE)x[(12085V/RPROG)-11,67uA]
RSENSE should be chosen according to the following equation: RSENSE=100mV/Imax
The required minimum resistance between PROG and GND can be determined by applying the suggested expression for RSENSE while solving the first equation given above for charge current with ICHRG = IMAX:
RPROG(min)=(12085 x RIN)/(0.1V+11.67uA x RIN
The charger presented in this schematic and based on the LTC4012 will provide an 12.6 volts output voltage at a maximum current of 4 amperes .
If you want to modify this design , to change the charging current or the output voltage please take a look to the datasheet , because you need to change the values for some components .