Flexible 4~20mA loop-powered pressure sensor transmitter with integrated voltage/current driver

　　Circuit functions and advantages

The circuit shown in Figure 1 is a robust and flexible loop-powered current transducer that converts the differential voltage output of a pressure sensor into a 4 mA to 20 mA current output.

The design is optimized for a variety of bridge-type voltage or current-driven pressure sensors, using only four active components and achieving a total unadjusted error of less than 1%. The loop supply voltage range is 12 V to 36 V.

The inputs of this circuit are ESD protected and provide voltage protection above the supply rails, making it ideal for industrial applications.

Figure 1. Robust loop-powered pressure sensor signal conditioning circuit with 4 mA to 20 mA output
(shown in sensor voltage drive mode), schematic: all connections and decoupling not shown