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Review of Jim Williams: AN25 Switching Regulators for Poets

Download AN25 Switching Regulators for Poets (1987, Linear Technology, 24 pages, 350KB pdf file)

IMPORTANT NOTE: This app note shows several high voltage circuits. You should not try to build them unless you have experience with the necessary safety measures. Please carefully note the warnings (in red) in the app note. For a general introduction to electrical safety you might want to take a look at the Electrical Safety chapter in allaboutcircuits.

The app note contains detailed discussions of several interesting circuits: The basic flyback regulator, a -48V to 5V flyback regulator, a fully isolated flyback regulator, a 100W off-line switching regulator, a switch controlled motor speed controller, and a switch-controlled Peltier 0C reference. All circuits use the LT1070 switching regulator ( AN19 the LT1070 Design Manual by Nelson offers very good information about this device - especially the Troubleshooting Hints starting on page 70 ). But the detailed descriptions of the circuits make them useful even if you want to use another device (if you already have experience with switching regulators).

Very good is Appendix C (starting on page 16): A Checklist for Switching Regulator Designs. The most common problems are discussed here: Inductor saturation, breakdown of semiconductor junctions during transient conditions, the parasitic characteristics of the capacitors, layout. The effects of diode turn-on and turn-off characteristics are discussed in detail.

You might also be interested in the other Application Notes by Jim Williams

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