Buck Boost Power Supply
The goal of this project is to design a power supply able to provide a voltage between 3 to 20V under 2 Amps from an input source included between 7 and 20V.
This power supply is in fact used to charge a 12V lead acid battery from another bigger one or from other power sources.
The efficiency of the system is a very important point, in the use case of a battery to battery charger, the maximum capacity of the source battery must be used to charge the second battery.
The power supply is composed of a buck part which is able to reduce the voltage and a boost stage to increase the voltage. Obviously, there is a current sense and the system is able to power under current and voltage output orders (This allows the respect charge cycle of a lead battery).
Here is an example of using the buck-boost module with a charge algorithm of a lead battery :
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