SLVAEW6 December 2020 TPS2661
- Trademarks
- 1Introduction
- 2Protection Required for Current Inputs in Analog Input Modules
- 3Typical Discrete Circuit for Protection of Current Input
-
4TPS26610 for Analog Current Loop
Protection
- 4.1 Current Input Protection with TPS26610
- 4.2 Accurate Current Limiting with TPS26610
- 4.3 Leakage Current of TPS26610 and Current Measurement Accuracy
- 4.4 Protection from Mis-wiring to Field Power Supplies
- 4.5 Heating and Temperature Rise with TPS26610
- 4.6 Reduction in PCB Size with TPS26610 for Current Input Protection
- 5Conclusion
3 Typical Discrete Circuit for Protection of Current Input
A discrete circuit consisting of TVS diode, Zener diodes and PTC is typically used for protection input. TVS diode provides protection from surge pulses, Zener diodes provide protection from over-voltage and PTC provides over-current protection.
Figure 3-1 illustrates an example of a discrete circuit for protection of current inputs in analog input modules. A PTC is required for required for over-current protection while Back-to-Back Zener diodes are required for over-voltage protection and limiting the power dissipation in Burden Resistor in case of miswiring to field supplies. Multiple burden resistors or a MELF resistors (MMB) are required in parallel to dissipate the power in case of miswiring events. A TVS diode is required to protect from surge transients.
Figure 3-1 Discrete Circuit for Current
Input Protection