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Application Notes

• Download
  Linear Technology Magazine Circuit Collection, Volume IV &mdash AN84
  PDF, 2.4 Mb, File published: Apr 1, 2000
  Application Note 84 is a collection of "power circuits" from the years 1996 through 1998 as seen in the pages of Linear Technology magazine. This Application Note collects circuits that can output tens of amps to circuits that can operate a handheld device for several years. In addition to a wide variety of traditional power supply circuits (Buck, Boost, Inverting, Flyback, Linear Regulators, etc.) we include circuits for charging batteries, several Power Management circuits as well as circuits that highlight a very low noise switching regulator.
  Extract from the document

  Application Note 84
  April 2000 Linear Technology Magazine Circuit Collection, Volume IV
  Power Products
  Richard Markell, Editor
  INTRODUCTION
  Application Note 84 is the fourth in a series that excerpts
  useful circuits from Linear Technology magazine to preserve them for posterity. This application note highlights
  “power” circuits from issue VI:1 (February 1996) through
  issue VIII:4 (November 1998). Another application note
  will feature data conversion, interface and signal processing circuits from the same era. Like its predecessor, AN 66,
  this Application Note includes circuits that can power
  most any system you can imagine, from “server” power
  supplies that generate in excess of 50 amps to micropower systems for portable and handheld equipment.
  Also included are power converters that can be voltage programmed using Intel’s VID code. Charge pump converters, linear regulators and battery charger circuits are
  included here, with Li-Ion batteries receiving extra attention. There are, of course, circuits that cannot be so simply
  categorized. Come browse. I’ll get out of the way and let
  the authors describe their creations.
  Note: Article Titles appear in this application note exactly
  as they originally appeared in Linear Technology magazine. This may result in some inconsistency in the usage
  of terminology. TABLE OF CONTENTS
  Introduction . 1
  REGULATORS—SWITCHING (BUCK)
  New LTCВ®1435–LTC1439 DC/DC Controllers Feature Value and Performance . 4 …

Design Notes

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  Step-Up/Step-Down DC/DC Conversion Without Inductors &mdash DN189
  PDF, 89 Kb, File published: Sep 2, 1998
  Extract from the document

  Step-Up/Step-Down DC/DC Conversion without Inductors
  Design Note 189
  Sam Nork A unique architecture allows the parts to accommodate
  a wide input voltage range (2.0V to 10V) and adjust the
  operating mode as needed to maintain regulation. As
  a result, the parts can be used with a wide variety of
  battery configurations and/or adapter voltages (Figure  2). Low power consumption (IQ = 60μA typical)
  and low external parts count make the LTC1514 and
  LTC1515 well suited for space-conscious, low power
  applications, such as cellular phones, PDAs and portable instruments. The parts come in adjustable and
  п¬Ѓxed output voltages and include additional features such as power-on reset capability (LTC1515 family) and
  an uncommitted comparator that is kept alive during
  shutdown (LTC1514 family).
  Regulator Operation
  The parts use a common internal switch network to
  implement both step-up and step-down DC/DC conversion. The action of the switch network is controlled by
  internal circuitry that senses the voltage differential
  between VIN and VOUT. When the input voltage is lower
  than the output voltage, the switch network operates as
  a step-up voltage doubler with a free-running frequency
  set by the internal oscillator (650kHz typ). When the input
  voltage is greater than the output, the switch network
  operates as a step-down gated switch. Regulation is …

Articles

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  Battery-Powered Buck-Boost Converter Requires No Magnetics &mdash LT Journal
  PDF, 195 Kb, File published: May 1, 1998
  Extract from the document

  DESIGN IDEAS Battery-Powered Buck-Boost
  Converter Requires No Magnetics
  by John Seago
  One of the problems that designers
  of portable equipment face is generating a regulated voltage that is between
  the charged and discharged voltage of
  a battery pack. As an example, when
  generating a 3.3V output from a 3cell battery pack, the regulator input
  voltage changes from about 4.5V at
  full charge to about 2.7V when discharged. At full charge, the regulator
  must step down the input voltage,
  and when the battery voltage drops
  below 3.3V, the regulator must step
  up the voltage. The same problem
  occurs when a 5V output is required
  from a four-cell input voltage that
  varies from about 3.6V to 6V.
  Ordinarily, a flyback or SEPIC configuration is required to solve this
  problem.
  The LTC1515 switched capacitor
  DC/DC converter, can provide this
  buck-boost function for load currents
  up to 50mA with only three external capacitors. The circuit shown in Figure 1 will provide a regulated 3.3V …

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Manufacturer's Classification

• Power Management > Inductorless (Charge Pump) DC/DC Converters > Regulated Step-Up Charge Pumps | Regulated Buck-Boost Charge Pumps