A Variable Switching Power Supply Using LM2576

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