Variable Switching Power Supply Using LM2576 [Buck Converter, CC-CV]
by sam_moshiri in Circuits > Electronics
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Variable Switching Power Supply Using LM2576 [Buck Converter, CC-CV]
![How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV]](/proxy/?url=https://content.instructables.com/F59/1D5N/JYSZAUS6/F591D5NJYSZAUS6.jpg&filename=How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV])
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
Schematic
![FIG1-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg](/proxy/?url=https://content.instructables.com/FBY/W9JT/JYSZAUVV/FBYW9JTJYSZAUVV.jpg&filename=FIG1-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg)
PCB Layout
![FIG2-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg](/proxy/?url=https://content.instructables.com/F1K/S2BZ/JYSZAVEN/F1KS2BZJYSZAVEN.jpg&filename=FIG2-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg)
A 3D/Real View of the Asemblde PCB Board
![FIG4-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg](/proxy/?url=https://content.instructables.com/FC3/W5O8/JYSZAUVZ/FC3W5O8JYSZAUVZ.jpg&filename=FIG4-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg)
![FIG5-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].JPG](/proxy/?url=https://content.instructables.com/F4Y/9IUZ/JYSZAV02/F4Y9IUZJYSZAV02.jpg&filename=FIG5-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].JPG)
Component Libraries (SamacSys)
![FIG3-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg](/proxy/?url=https://content.instructables.com/FDM/J7VE/JYSZAUVY/FDMJ7VEJYSZAUVY.jpg&filename=FIG3-How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV].jpg)
References
Article source: http://bit.ly/2YshM5t
LM2576 Datasheet: https://www.onsemi.com/pub/Collateral/LM2576-D.PDF
LM358 Datasheet: https://www.onsemi.com/pub/Collateral/LM358-D.PDF
LM2576 Library: https://componentsearchengine.com/part-view/LM2576TV-ADJG/ON%20Semiconductor
LM358 Library: https://componentsearchengine.com/part.php?partID=671517
Altium Plugin: https://www.samacsys.com/altium-designer-library-instructions