Switching power supplies are known for high efficiency. An adjustable voltage/current supply is an interesting tool, which can be used in many applications such as a Lithium-ion/Lead-acid/NiCD-NiMH battery charger or a standalone power supply. In this article, we will learn to build a variable step-down buck converter using the popular LM2576-Adj chip.
Features
Cheap and easy to build and use
Constant current and constant voltage adjustment [CC, CV] capability
1.2V to 25V and 25mA to 3A controlling range
Easy to adjust the parameters (optimum use of variable resistors to control the voltage and current)
The design follows the EMC rules
It is easy to mount a heatsink on the LM2576
It uses a real shunt resistor (not a PCB track) to sense the current