Switching regulators are designed for low idle power
Switching regulators from Recom were developed specifically to supply microprocessors from 4.0 to 20mA loop. The R420-1.8/PL flat module switching regulators have low idle power, with high efficiency, says the company.
The long-serving analogue 4.0 to 20mA loop is the accepted standard in process and control technology, largely due to the relatively simple two-wire technology, which is easy to install and reliable. Supplying digital components from the unused portion of the loop current had become an issue with microprocessors processing raw data and Highway Addressable Remote Transducer (HART) modems ensuring that smart sensors keep sending a variety of data signals on the same loop.
Conventional switching regulator ICs are unsuitable as their high efficiency at full load drops at lower loads causing them to exceed the 4.0mA threshold. Low quiescent current in sleep mode cannot compensate, as this shuts off the main output voltage altogether. Linear regulators; despite good quiescent current levels at around 0.5mA, have poor efficiency to decrease available power by a factor of around three, compared to switching regulators.
The R420-1.8/PL switching regulators use topology that is capable of lowering idle current to around 100microA while still maintaining rated voltage at output. For example, 24V DC and less than 3.5mA at the input provides 3.3V and 10mA at the output, which is capable of supplying the sensor alongside the microcontroller and HART modem without affecting loop functionality or metering accuracy, claims the company.
The regulators are also programmable for any output voltage between 1.8 and 5.0V by simple wiring using a resistor. This yields a single component suitable for a variety of tasks in process automation or sensor-controlled, solar-powered systems, points out the company. The R420-1.8/PL features an open-frame SMD design and operates at -40 to +105°C. Modules operate at an altitude of up to 5,000m. The regulator is permanently protected against short-circuit, and carries a three-year warranty.