Sensor Technology and Integrated Power Supply

Encoders, light barriers, optical sensors, and controls are frequently used in industrial applications. In most cases, they are supplied with power through long lines with 24 V voltage.

But this voltage is not consistent. It can fluctuate between +/- 50% and it can be further interrupted by low frequency noise and other glitches. This won’t do in some fields, for instance, sensor technology. In such cases, custom power supplies have proven to be viable alternatives.

In sensor technology, the analog circuits are very high precision. The power supply to such applications must be as glitch-free and precise as possible. For example, microcontrollers and some components of digital circuits have supply tolerances of +/-5% with <50 mV ripple.

But if the sensor has both digital and analog circuit components, it will need two supply voltages. This combination can lead to crosstalk, ground displacements or glitches in supply voltage. Consequently, these separate requirements will lead to a split up of the voltage supplies.

One way to cope with this is to use linear regulators. But in some cases, these show high power dissipation. This can be reduced by applying a DC/DC converter upstream. But be careful, because it can increase the space requirement of the voltage supply. In such cases, the embedded engineer will have to adopt an integrated solution to eliminate the disadvantages of the hybrid architecture.