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To implement a 12 V SLA battery charger, you have two routes.
1) Use a dedicated multi-stage charger IC such as BQ24650 www.ti.com/.../bq24650.pdf
2) Design a discrete charger circuit, which will be more difficult.
3 terminal regulators, such as the LM338 and LM1086, regulate the Vadj voltage across the upper voltage divider resistor R1 or Rs + R1 in the battery charger examples below. This is different from more recent linear regulators that regulate the Vref or Vfb voltage across the lower voltage divider resistor R2. The following examples' equations will not apply to the LM2941C.
Examples of 12 V discrete battery charger circuit for 3 terminal linear regulator is shown:
LM338 datasheet Figure 41 simple charger: www.ti.com/.../lm338.pdf
LM338 datasheet Figure 34 shows a more complex charger circuit.
If you want to charge your 12 V SLA battery at a fixed voltage, you could set your LM2941C Vout to 13.6 V. Charge time will be greatly increased compared to a multi-stage charger, but the circuit is much simpler. The SLA battery cannot be connected to the charger indefinitely at 13.6 V, as damage will occur to the battery. Constant voltage or constant current charging can impact battery life.
I have checked the LM338 and LM1086, But In order to reduce the BOM I have considered using LM2941C regulator for the"EN" option instead of using one of these with MOSFET.
I think I have no choice but to use LM338 or LM1086 with MOS transistor.
