Datasheet Linear Technology LTC1709-7 — Datenblatt

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  Active Voltage Positioning Reduces Output Capacitors &mdash Design Solutions 10
  PDF, 130 Kb, Datei veröffentlicht: Nov 1, 1999
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  Design Solutions 10
  November 1999
  Active Voltage Positioning Reduces Output Capacitors
  by Robert Sheehan
  INTRODUCTION
  Power supply performance, especially transient response,
  is key to meeting today’s demands for low voltage, high
  current microprocessor power. In an effort to minimize
  the voltage deviation during a load step, a technique that
  has recently been coined “active voltage positioning” is
  generating substantial interest and gaining popularity in
  the portable computer market. The benefits include lower
  peak-to-peak output voltage deviation for a given load
  step, without having to increase the output filter capacitance. Alternatively, the output filter capacitance can be
  reduced while maintaining the same peak-to-peak transient response.
  BASIC PRINCIPLE
  The term “active voltage positioning” (AVP) refers to
  setting the power supply output voltage at a point that is
  dependent on the load current. At minimum load, the
  output voltage is set to a slightly higher than nominal level.
  At full load, the output voltage is set to a slightly lower than
  nominal level. Effectively, the DC load regulation is
  degraded, but the load transient voltage deviation will be …

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  Dual-Phase High Efficiency Mobile CPU Power Supply Minimizes Size and Thermal Stress &mdash DN247
  PDF, 91 Kb, Datei veröffentlicht: Dec 15, 2001
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  advertisement Dual-Phase High Efficiency Mobile CPU Power Supply
  Minimizes Size and Thermal Stress
  Design Note 247
  Wei Chen
  Introduction
  The increasing demand for computing power in
  notebook computers has significantly increased CPU
  clock frequencies and supply currents. Forthcoming
  mobile CPUs call for core currents as high as 25A to
  handle sophisticated computing tasks. Traditional
  single-phase solutions have difficulty delivering such
  a high current. When the CPU supply voltage (0.7V to
  1.8V) is converted directly from a high voltage (21V
  max) adapter input, single-phase MOSFET drivers are
  not strong enough to efficiently drive high current
  MOSFETs without dV/dt shoot-through problems. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are
  registered trademarks of Linear Technology Corporation. All other trademarks
  are the property of their respective owners. 10О© 1000pF
  INTVCC 10О© R3 10k 2.7k The resulting excessive power loss in the MOSFETs
  increases thermal stress close to the CPU and reduces
  the battery run time. The physical size of a high current (25A) inductor becomes unacceptably large and
  more low ESR output capacitors are required to handle
  larger load steps. Also, current crowding in PCB traces …

Artikel

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  PolyPhase Switcher Reduces Parts Count for Smaller, Less Expensive Mobile CPU Supply &mdash LT Journal
  PDF, 363 Kb, Datei veröffentlicht: Sep 1, 2000
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  DESIGN IDEAS PolyPhase Switcher Reduces Parts
  Count for Smaller, Less Expensive
  Mobile CPU Supply
  by Wei Chen
  Introduction
  the LTC1709-7 allows lower cost,
  lower profile parts to be used and also
  improves transient response.
  The LTC1709-7 is a dual, current
  mode, PolyPhase controller that drives
  two synchronous buck stages 180В°
  out of phase. This small, SSOP-36
  packaged controller integrates four
  high current MOSFET drivers, a differential amp for true output remote The LTC1709-7 takes advantage of
  PolyPhaseв„ў switching techniques to
  reduce the number of input capacitors
  and the inductor size and to increase
  battery life. As CPU clock frequencies
  increase, the demand for core supply
  current also increases. Today’s 22A
  CPU core current requirements push
  single-stage switchers to the max.
  The PolyPhase switching designed into sensing, automatic current sharing …

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• Power Management > Switching Regulator > Digitally Programmable Regulators