termi iii ealniteeea
`
`oer
`bee
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`POWER
`iaa
`CIRCUITS
`Rudolf P Severns
`Gordon E. Bloom
`
`Poe
`
`Ex.1015
`APPLE INC. / Page 1 of 5
`
`

`

`MODERN
`D
`DC-TO-DC
`SWITCHMODE
`POWER
`co
`CONVERTER
`C
`CIRCUITS
`
`Rudolf P. Severns
`rn
`Senior Staff Engineer
`Applications Engineering
`SILICONIX, INC,
`
`Gordon (Ed) Bloom
`Senior Partner and Engineering Specialice
`6/] BLOOM Associates
`
`Van Nostrand Reinhotd Electrical(Computar Science and Enginsering Series
`V n
`En
`,1
`In
`
`[aa] VAN NOSTRAND REINHOLD COMPANY
`
`
`
`NewYork
`
`
`
`Ex.1015
`APPLEINC./ Page 2 of 5
`
`Ex.1015
`APPLE INC. / Page 2 of 5
`
`

`

`Copyright © L985 Sy RuGolf P. Sewers and Gordon Btocen
`
`Litrary of Congress Catalog Card Notber: 84-120726
`ISBN: 0442.213%-4
`
`hereon may
`AD rights steered. No part of this work covered by ae
`be etpecdaced uy aged in) enp Comm oc by amy mesreSOTION, OF
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`aadpeta, nctoding piectncopying, seceeting, taptes, of storage
`and recrices) systemd—without perssission ofthepublisher.
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`Mesufaccured in the Weited States of America
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`Published by
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`l • J
`
`Litrazy of Congress Cataloging in Publication Dare
`
`Severs, Radel P,
`Modern DC-to-DC swhehmmed: power converter chreuks.
`
`electricalcomputer science and
`
`(Ven Nostrand
`engiveering series)
`‘p.
`iastntis baen,
`* derec typaraens and sppliances-Power sepgty
`2. Microelectronics—Powe: supply.
`1, Boom, Gorden.
`ATithe, Uf. Tithe: Modera [XC-10-DC switchrmede
`TKRPEST. 106
`621.3415 32
`&4-12006
`
`ooawemercheuke
`
`IV, Series
`
`ISBN 0-442-21 396-4
`
`i
`
`Ex.1015
`APPLEINC./ Page 3 of 5
`
`Ex.1015
`APPLE INC. / Page 3 of 5
`
`

`

`0
`COMBINATIONS OF CONVERTERS
`
`158
`
`iL im Fig. 7.44 a5 an essential SPC fearwre and, by processes of rotation and
`or-imaging, used ta logically evolve buck or boost SPC topologies.
`As we have seen, it is possible by 9 simple manipulation to derive the buck-
`t converter topoloay from the cascade conmection of the two elerpentary
`. The derivation of the bucktous! SPC small-signal model given in
`ex 10 also supports this view, For these reasons, we have chosen here to
`the buck-beost converter as a special combination of buck and boost
`Cs, rather than ant elementary comverter unto itself. Since this assumption has
`n to be self-consistent, we have retained it throughout the discussions of this
`4, but certainty the point of origin of this converter topology is an arguable
`
`ms
`
`When multiple cutpets and/or DC trolation from input to output are desired
`a buck-boost converter, It is mot necessary to incorporate a DC transformer,
`we will see. Consider the buck-Doost circuit of Fig. 75A, where the inductor
`now has two identical windings & parallel. This winding addition does not
`the bacle converter operation. Next, the links commecting the ran indurctne
`dings are removed, a4 shown in Fig. 7.5A. Again, circuit operation remnains
`same except that DC trolation between the inpwt and the oetput has been
`j. The final step in this process is shown in Fig. 7.5C, where additional
`ondary windings have been introduced im the inductor assembly with arbitrary
`ratios relative to the inductor “primary.” This transfoemer4solated multiple-
`form of the buck-Doost SPC ts called the ftyback converterand is probably
`put
`t most popular circuit im wee today for ourput power levels below 50 W.
`primary advartage is simplicity, particularly in that only one magnet com
`jonent
`is meeded, even when input-to-ostput DC isolation asd/or multipie our-
`are required from the converter. The primary difficulty associated with
`SPC is the design ofinductor L, which now essumes the roles of both an
`y-torage device and a transformer element, Its design becomes even more
`cult when multiple oulpets with good cross regulation are required, Success-
`flyback SPC design examples with as many a8 25 isolated ourputs do exist,
`their magnetics designs were very complicated.
`Besides the pabating input and output current characteristic and the high
`itch
`currents mentioned earlier, the comtrol-to-output small-signal transfer
`tion of the buck-boost has a right half-plane cero, as we will see in Chapcer
`). The presence of this trowbesome zero should comeas no surpre since one
`the elementary constituents of the buck-boost converter has @ similar comtrol-
`D-owtput transfer function.
`When # buck SPC is preceded by a boost SPC, as shown in Fig. 744A, quite
`| different, and in many ways a more useful comverter can be derived in much
`same manner as was followed to evolve the buck-boost and flyback SPCs. In
`7.6B, the two switch-and-diode sets are replaced by 2 singke DPDT switch.
`this case, Cl cannot be omitted aimee It Is required for energy storage. As was
`
`Ex.1015
`APPLEINC./ Page 4 of 5
`
`Ex.1015
`APPLE INC. / Page 4 of 5
`
`

`

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`D
`
`Ex.1015
`APPLE INC. / Page 5 of 5
`
`