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

5 Conclusion

With accurate current limiting, low leakage currents, over-voltage and under-voltage protections, TPS26610 device offers a more compact and accurate solution for current input protection in analog input modules. Table 5-1 summarizes the comparison between current input protection with TPS26610 and with discrete circuit.

Table 5-1 Comparison of TPS26610 with Discrete Circuit for Current Input Protection
Current Input Protection with TPS26610 Current Input Protection with Discrete Circuit

Error due to leakage currents

(-40 to 125°C)		 0.0005% 1.6%

Current Limit Accuracy

(-40 to 125°C)		 ±17% ±50%
Over-voltage and under-voltage Cut-off protection for miswiring faults Yes No
Estimated PCB Area 43 mm2 102 to 142 mm2
Lower Noise and Higher ENOB with 249Ω Burden Resistor without increase in leakage currents Yes No
Temperature Rise in miswiring faults (Above Ambient Temperature) 15°C 95°C
Voltage Drop in Loop 150 mV 800 mV (with 40Ω PTC)