SLVAE51A November   2018  – October 2020 LM7310 , TPS2100 , TPS2101 , TPS2102 , TPS2103 , TPS2104 , TPS2105 , TPS2110 , TPS2111 , TPS2111A , TPS2112 , TPS2112A , TPS2113 , TPS2113A , TPS2114 , TPS2114A , TPS2115 , TPS2115A , TPS2120 , TPS2121 , TPS25947

 

  1.   Trademarks
  2. 1What is a Priority Power MUX?
  3. 2Control Method
    1. 2.1 Manual
    2. 2.2 Automatic
    3. 2.3 Both - Automatic + Manual Override
  4. 3Power MUX Topologies
    1. 3.1 Discrete
    2. 3.2 Semi-Integrated
    3. 3.3 Fully Integrated
  5. 4Switchover Method
    1. 4.1 Break-Before-Make vs. Diode Mode
    2. 4.2 What is Seamless Switchover?
    3. 4.3 Output Voltage Drop
    4. 4.4 Inrush Current
  6. 5Additional Protection
    1. 5.1 Overvoltage Protection
    2. 5.2 Overcurrent Protection
  7. 6Summary
  8. 7References
  9. 8Revision History

4.1 Break-Before-Make vs. Diode Mode

There are two sets of switchover methods that power MUX solutions fall under:

  1. Break-before-make method occurs when the switch for the first supply completely turns off before the second supply switch is turned on.
    1. This prevents reverse current flow from one supply to another.
    2. There is a period of time where no power is being delivered from the supply to the output. This is known as the switchover time, or tSW.
  2. Diode mode is a make-before-break method where the diode or switch for the first supply remains on while the second supply switch is turned on. Reverse current is then prevented by the presence of a diode or a device which detects the reverse current flow and shuts off a corresponding FET (such as our eFuse, Ideal Diode or ORing controllers).
    1. The benefit of this approach is minimal output voltage drop, as power is continuously supplied to the load.
    2. The tradeoff depends on what diode device is used:
      1. Schottky or Silicon diode will result in power dissipation and voltage drop during normal operation.
      2. eFuse, ORing or Ideal diode controller methods will result in some level of reverse current flow, potentially significant or insignificant depending on the application.