JAJSK33A April 2022 – September 2023 TPS38
PRODUCTION DATA
In many industrial and factory automation applications, there are multiple power rails that power various subsystems within the application. Some of these power rails include 24 / 48 VAC AC sources with a known operating frequency that requires a full-bridge rectifier and capacitors to convert its signal to a DC voltage where it can be monitored by a voltage supervisor. One drawback with the described conversion is the response time of the DC voltage when the AC power rail experiences a change of operating frequency or voltage amplitude. Due to the output filter of the full-bridge rectifier, the detection in the change of voltage or operating frequency may require several AC cycles before the voltage supervisor outputs a fault condition. The direct monitoring of the AC source by using a “Resistive-Drop” supply topology circuit provides the user a fast transient fault detection. In this design example, the TPS38 adjustable version is being highlighted with the ability to offer a unique solution by monitoring the output of the AC source for undervoltage operation.