SLVAEW6 December   2020 TPS2661

 

  1.   Trademarks
  2. 1Introduction
  3. 2Protection Required for Current Inputs in Analog Input Modules
    1. 2.1 Over-Current Protection from Miswiring to Field Power Supplies
    2. 2.2 Over-Voltage Protection from Miswiring to Field Power Supplies
  4. 3Typical Discrete Circuit for Protection of Current Input
    1. 3.1 Protection Provided by Discrete Circuit
      1. 3.1.1 Over-Current Protection with Discrete Circuit
      2. 3.1.2 Over-voltage Protection with Discrete Circuit
    2. 3.2 Heating and Temperature Rise with Discrete Circuit
    3. 3.3 Reverse Leakage Current of Zener Diodes and Current Measurement Accuracy
  5. 4TPS26610 for Analog Current Loop Protection
    1. 4.1 Current Input Protection with TPS26610
    2. 4.2 Accurate Current Limiting with TPS26610
    3. 4.3 Leakage Current of TPS26610 and Current Measurement Accuracy
    4. 4.4 Protection from Mis-wiring to Field Power Supplies
    5. 4.5 Heating and Temperature Rise with TPS26610
    6. 4.6 Reduction in PCB Size with TPS26610 for Current Input Protection
  6. 5Conclusion

2.1 Over-Current Protection from Miswiring to Field Power Supplies

In the factory environment, a voltage source for example, 24 V power supply, can be miswired to a current input. The voltage source will lead to excessive current flow through the burden resistor and may burn the burden resistor. An over-current protection device with bi-directional current limiting (similar to PTC) is used traditionally to limit the current in the burden resistor.