5V & 3.3V Hot Swap Controller

Reference Design LogoThis reference design implements a hot swap controller design within a Power Manager II mixed-signal PLD. The design manages 5V and 3.3V supply rails to limit inrush current to a user-defined level. It also initiates a shut-down if either supply exhibits a short-circuit. By sensing the voltage across the MOSFET and limiting the inrush current, the design operates the transistors in the Safe Operation Area (SOA).



  • 5V and 3.3V hot-swap controller
    • Operate MOSFETs in Safe Operation Area (SOA)
    • Short circuit protection
    • Protection against over current faults during operation
  • Programmable SOA and over current levels for both 5V and 3.3V
  • Customize the design to suit most MOSFETs
  • Initial contact de-bounce period programmable from 32us to 2 seconds

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Block Diagram

5V & 3.3V Hot Swap Controller

Performance and Size

Tested Devices* Macrocells Product Terms VMONs I/Os Timers Revision
ispPAC-POWR1014A 13 56 6 2 2 1.0

* May work in other devices as well.

Note: The performance and design sizes shown above are estimates only. The actual results may vary depending upon the chosen parameters, timing constraints, and device implementation. See the design's documentation for details. All coding and design work was done on a PC platform unless noted otherwise. 


Technical Resources
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5V and 3.3V Hot Swap Controller - Source Code
RD1057 1.0 8/6/2009 ZIP 135 KB
5V and 3.3V Hot Swap Controller - Documentation
RD1057 1.0 8/4/2009 PDF 185.3 KB

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