SMPS with Battery Backup and NiMH Charger

I designed this circuit for the same reason that i designed the SMPS Boost regulator with the MCP1640 – To gain experience in SMPS technology. This time i use the high power LM2595 buck regulator.The circuit accepts any AC voltage from 8 to 45 Volts.

SMPS with Battery Backup and NiMH Charger

This wide input voltage range is a remarkable feature! Plus, it can provide up to 1 ampere of current at 5 volts! Imagine what wold take to design a linear power supply to provide 5V 1A power from 45 volts! A huge power dissipation of 40 Watts! Your soldering iron provides probably less heat! The LM2595 has an efficiency which varies from 75% to 95%. Typically, the previously descried system has an efficiency of 80%, which means that the system will dissipate about 1 Watt of heat…
The AC input is rectified through the B1 bridge rectifier. A U LC filter decouples the circuit from the input (C4,L1,C1) and smooths the input voltage. The R1-R2 voltage divider along with the charge capacitor C3 perform a delay-startup. This part may be omitted if the delay-startup is not necessary. The heart of the circuit is the LM2595 with the catch diode D1, the inductor L2 and the filtering capacitor C2. This is where the step-down is done.
I’ve included several outputs. X1-6,7 and 8 are the PSU outputs. X1-6 is the ground terminal. X1-8 provides a rectified and filtered output of the raw AC input. Remember to calculate the RMS to peak conversion. If for example the AC input is 24VAC, the output at this terminal will be 34 Volts DC. The output X1-7 provides 5V to power any external circuit needed.
For more detail: SMPS with Battery Backup and NiMH Charger

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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