Low-cost 12V - 50W off-line switching power supply

This is a simple low-cost 12 Volt 50W off-line switching power supply, which can be used for home projects or to learn operation of flyback converters. It can work over a universal AC line input range 90-264 VAC and provides a 12VDC output at more then 4A load. Line and load regulation is better then 0.5%. The unit has overcurrent, overtemperature and overvoltage protections as well as passive inrush current limiting. Output ripple are approximately 0.2 V. If you need to get lower ripple, you may put an additional output LC filter.

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Comments

The Holy Avenger said…

The toroid heats up to 87'C @ 1.1A / 12V load. The toroid I used was not the one recommended ( not available in my country). The Toroid specs were: ID = 0.6 inch, 2 were paralleled, color was yellow/ white, Lp=200uH, Rp=113mR, Gauge=SWG#22 (0.71mm), Secondary Wire gauge 0.75mm2, Aux = 0.125mm2 both were rubber insulated. Combined AL was 178nH/T2

Then I tried a different bigger core: ID=0.8 inch, 2 paralleled, color was green/blue, Gauge of pri was SWG#23(0.61mm2). Combined AL was 183 nH/T2

February 15, 2010 at 10:56 PM

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