The purpose of the development is to create a low-noise uninterruptible power supply capable of supplying a telluric current measuring and recording instrument at 5V and ±22V levels. ± 22V supplies the analog circuits in the instrument, while the 5V supplies digital units, including a data management and a DCF unit. The uninterrupted power supply has two power inputs, 230V/50Hz low voltage network and a 12V battery. The power supply is charging the battery while the main is available, and in case of black out, the battery will provide the energy for the instrument.
The critical point of the development is that the operational mode changing should be performed without voltage drop on the 5V output line. If the 5V drops below a critical level for a long time, the data collector and the digital unit may stop recording (power reset), which may result in data loss.
These voltage levels (5V and ± 22V) are frequently used in instruments. That means, with the appropriate dimensioning of the inductive components, we can get a power supply that can be used with more instruments without changing anything at the system architecture.