The LTC®4353 controls external N-channel MOSFETs to implement an ideal diode function. It replaces two high power Schottky diodes and their associated heat sinks, saving power and board area. The ideal diode function permits low loss power supply ORing and supply holdup applications.
The LTC4353 regulates the forward-voltage drop across the MOSFET to ensure smooth current transfer in diode-OR applications. A fast turn-on reduces the load voltage droop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.
The controller operates with supplies from 2.9V to 18V. If both supplies are below 2.9V, an external supply is needed at the VCC pin. Enable inputs can be used to turn off the MOSFET and put the controller in a low current state. Status outputs indicate whether the MOSFETs are on or off.
- Low Loss Replacement for Power Diodes
- Controls N-Channel MOSFETs
- 0V to 18V Supply ORing or Holdup
- 1μs Gate Turn-On and Turn-Off Time
- Enable Inputs
- MOSFET On-Status Outputs
- 16-Lead MSOP and DFN (4mm × 3mm) Packages
Linear Technology’s LTC4353 is a 0V to 18V dual diode controller that is designed to replace two high power Schottky diodes to provide low loss ORing of multiple power sources with minimal disturbance to supply voltages.
The device regulates the forward voltage drop across external N-channel mosfets to ensure smooth current transfer between supplies in diode-OR applications.
In low voltage systems, a slow handoff between controllers results in a voltage droop during supply switchover.
The turn on time is less than 1µs.
In the event the input supply fails or is shorted, a fast turn-off minimises reverse current.
The LTC4353 provides individual enable inputs that can be used to ensure priority to the main supply when supply voltages are within a mosfet body diode drop of each other.
For more read: Dual diode controller two high power Schottkys replaces