Datasheet Linear Technology LTC4055EUF#PBF

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LTC4055-1

Design Notes

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  Advanced Topology USB Battery Charger Optimizes Power Utilization for Faster Charging &mdash DN336
  PDF, 74 Kb, File published: Apr 3, 2004
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  Advanced Topology USB Battery Charger Optimizes Power
  Utilization for Faster Charging – Design Note 336
  John Shannon
  Linear Technology offers a variety of parts to simplify
  the task of extracting power from a USB cable, including
  the new, easy-to-use LTCВ®4055 high performance Li-Ion
  charger and power controller. The LTC4055 seamlessly
  manages power flow between an AC adapter, USB cable
  and Li-Ion battery, all while maintaining USB power
  specification compliance.
  Thanks to its sophisticated intermediate voltage bus
  topology, the LTC4055 charges batteries faster with
  less heat generation than a traditional charger-fed
  topology. Better yet, a typical LTC4055-based USB
  charger solution is compact and requires only 10
  external components and 100mm2 of PCB real estate.
  Benefits of the LTC4055
  In order to fully appreciate the benefits of the LTC4055,
  let us п¬Ѓrst analyze the difference between the intermediate voltage bus topology and a charger fed topology.
  Figure 1 is a simplified block diagram of the two power
  topologies. In the intermediate bus voltage topology,
  the output called VMAX is derived from one of the three
  available power sources—wall adapter, USB or battery. …

• Download
  Simple Battery Circuit Extends Power over Ethernet (PoE) Peak Current &mdash DN361
  PDF, 82 Kb, File published: Feb 17, 2005
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  Simple Battery Circuit Extends Power over Ethernet (POE)
  Peak Current – Design Note 361
  Mark Gurries
  Introduction
  Power over Ethernet (PoE) is a new development that allows for the delivery of power to Ethernet-based devices
  via standard Ethernet CAT5 cable, precluding the need
  for wall adapters or other external power sources. The
  PoE specification defines a hardware detection protocol
  where Power Sourcing Equipment (PSE) is able to identify
  PoE Powered Devices (PDs), thus allowing full backwards
  compatibility with non-PoE-aware (legacy) Ethernet devices. The PoE specification also sets an upper limit
  on the power that can be drawn by a PD. The problem
  is: what happens when a PD must draw more power
  than allowed by the PoE standard? Examples may be
  the spin up of a disk drive or a period of sustained
  transmission of data from an RF transmitter. If the
  average power load of these applications is less than
  L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks
  and PowerPath is a trademark of Linear Technology Corporation. All other
  trademarks are the property of their respective owners. L1
  3.3ОјH
  C2
  1ОјF …

Articles

• Download
  USB Power Controller/Charger Reduces Both Design Time and Battery Charge Time &mdash LT Journal
  PDF, 157 Kb, File published: May 1, 2004
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  DESIGN FEATURES USB Power Controller/Charger
  Reduces Both Design Time
  by Roger Zemke
  and Battery Charge Time
  Introduction 3.85V
  370mA Li-ION
  AT 3.85V 1Ω IN1 OUT IN2 BAT VNTC 10µF NTC SUSPEND USB POWER SUSP 500mA/100mA SELECT HPWR
  CLPROG 100k GND 100k Figure 1. Standalone USB Li-Ion battery charger with PowerPath control from input to output and
  battery to output—configured for 500mA USB current limit and 500mA maximum charge current. dead. The same reasoning applies for
  fully charged batteries. A fully charged
  battery, which is not in the power path
  until the USB or external power is removed, stays fully charged. Figure 1
  shows just how simple the PowerPath
  control and battery charging in a USB
  application can be implemented using
  the LTC4055. PowerPath
  Let’s examine how PowerPath control
  reduces charge time. Assume the application load is a DC/DC converter.
  Such converters are effectively constant power devices. The higher the
  input voltage to the DC/DC converter
  the lower the current draw. In a USB
  application where the current is
  500mA 0.2Ω 4.98V 400mA 100mA 130mA limited, it makes sense to run the …

Model Line

Manufacturer's Classification

• Power Management > PMIC & Multifunction > USB Power Manager (PowerPath, Battery Charger)

Other Names:

LTC4055EUFPBF, LTC4055EUF PBF