`
` DANIELM. MITCHELL
`
`laAE
`
`StaNE:
`REGUIATOR
`
`DC =
`
`DC
`
`ANKER 1019
`
`1
`
`
`
`Regulator
`Analysis
`
`Daniel M. Mitchell
`Advanced
`
`
` DC-DC Switching
`
`
`
`Rockwell international Corporation
`Codar Rapicts
`Adjenct instrwctor
`Department of Electrical and Computer Engineering
`vtreratly uf fore
`
`tows City
`
`2
`
`
`
`Library of Congress Cutaloging-in-Publicotion Duta
`
`Mitchell, Duniel M
`DC-DC awitching regulator arelysis.
`
`1. Electronic apparatus and appliances—Power
`supply—Direct current.
`1, Title
`TKTA63.PeoSs 1968«=G21.BS aT.1ere
`ISEN 0.07.0462507-3
`
`PealactaeAmarin, Beyaspomied
`ievtewt StatesofAmerica.In vied as
`
`
`
`
`under the United States Copyright Act of 1976, no part ot this
`publication may be reproduced or distributed in any form or
`by any manna, o¢ stored in « data base or retrieval eystern,
`weheut the prior written permission ofthe publisher.
`128466Tee9 DOC/DOC sez10887
`
`ISBN 0-07-04259?-3
`
`The editors for thie book were Danief A. Gonneca and Lucy Mullins,
`the designer wes Noomi Aacrboch, and the production supervisor
`wus Dianne Waiber. It wos act ix Century Sehoolbook
`by Techns Type, Ine,
`Printed end bound by RR. Donnelley & Sons Company.
`
`
`
`3
`
`
`
`
`
`38
`
`OC-DC Smiltching Reguistor Anatyws
`
`Figure 3.2 shows a simple PWM controller with a fixed-frequency
`fixed-amplitude sawtooth signal applied to the basic buck converter.
`The width of the PWM ON pulse is the time between the reset of the
`sawtooth generator and the intersection of the error voltage with the
`pasitive-going sawtooth signal, or ramp. If u, is the error voltage am-
`plitude, which is assumed to change slowly with respect to the switch-
`ing frequency, and V, is the sawtooth voltage amplitude, then the duty
`factor can be approximated by the continuous expression
`
`d-—
`
`(3.2)
`
`
`
`
`ADS
`
`,
`
`Ac,» tM,
`
`4
`
`