Datasheet Linear Technology LTC4359

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  Ideal Diode Combines 200V Busses &mdash LT Journal
  PDF, 92 Kb, File published: Apr 9, 2014
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  Ideal Diode Combines 200V Busses
  Mitchell Lee As the power consumption of individual cards increases in rack-mounted
  systems, current consumption necessarily follows suit. A point is reached
  where the current delivered by the backplane becomes untenable, and the only
  solution is to increase the bus voltage. This point has been reached in even
  some 48V systems, leading to the use of bus voltages exceeding 100V.
  The LTC4359 ideal diode controller is used
  in 12V, 28V and 48V battery, vehicular,
  line operated and solar power systems as
  a blocking diode and diode OR, achieving
  substantially lower power and voltage
  loss than is possible with a conventional
  diode. Its 100V absolute maximum rating
  would seemingly preclude use in higher
  voltage applications, but with the addition of a simple source follower clamp,
  this limitation is easily overcome. When power is first applied, Q1’s body
  diode passes current to the output. Q3, a
  600V depletion mode device, turns on and
  connects the output voltage directly to the
  LTC4359’s OUT pin. The IN and OUT pins
  sense VSD across Q1 and drive the GATE pin
  in an attempt to hold the MOSFET’s “forward” drop to 30mV. This condition is
  maintained up to about 1.5A, beyond which Q1 is driven fully on and the voltage drop is dictated by its 20mО© RDS(ON). …

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  Low IQ Ideal Diode Controller with Reverse Input Protection for Automotive and Telecom Power Solutions &mdash LT Journal
  PDF, 248 Kb, File published: Jan 17, 2017
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  design features Low IQ Ideal Diode Controller with Reverse Input Protection
  for Automotive and Telecom Power Solutions
  Meilissa Lum Blocking diodes are widely used in power supplies to solve a variety of problems.
  In automotive systems, a series blocking diode protects against accidental reverse
  battery connections when the battery is replaced or the car is jump started. High
  availability systems and telecom power distributions employ blocking diodes to
  achieve redundancy by paralleling power supplies. Diodes are also used to prevent
  discharge of reservoir capacitors in situations where some temporary holdup of
  output voltage is necessary to ride through input dropouts or noise spikes, or to
  allow the load to gracefully power down when the input supply abruptly fails.
  While blocking diodes are easy to understand and apply, their forward drop results
  in significant power dissipation, making
  them unsuitable in both low voltage and
  high current applications. In low voltage
  applications, the forward voltage drop
  becomes a limiting factor for a circuit’s
  operating range, even when using a
  Schottky barrier diode. At least 500mV of
  supply headroom is lost across a series
  diode—a substantial degradation in 12V
  automotive systems where the supply can
  drop to as low as 4V during cold crank.
  Since diodes operate at a fixed voltage …

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Manufacturer's Classification

• Monitor, Control and Protection > PowerPath Controllers & Ideal Diodes
• Space & Harsh Environment > Extended Temperature Plastic (H & MP) > Extended Temperature (H & MP) Power Management