SIGNAL CHAIN BASICS #42: The Digital Isolator, a new member of the signal chain family
Continuous changes in legislation with regards to designing electronic systems in industrial applications call for the implementation of galvanic isolation into almost any electronic circuit design. The two main reasons for using galvanic isolation are:
- increased safety, which basically aims to prevent potential damage to equipment or humans due to high-energetic current or voltage surges, and
- highly reliable data transmission, which focuses on the increased signal robustness of remote data links with different ground potentials and to prevent disruptive ground loop currents.
While the first case is easily understandable, the second one requires some further explanation. The various nodes of a communication network commonly use local grounds as their reference potential. Thus, remote-located nodes draw their supply from different points in the electrical installation system. Remote-located power sources, however, can experience large ground-potential differences due to multiple, non-standardized, earthing techniques, which are also the cause for multiple ground paths.
When providing a direct connection between the transmitter ground and a remote receiver ground, for example by the means of a ground wire, an unintentional ground loop is created. Ground loop currents can be extremely high, because they connect different ground potentials via low-impedance wire (Figure 1).
Figure 1: Eliminating ground loops through galvanic isolation.
(Click on image to enlarge)
These ground loop currents then induce voltages into transmission signal wires, causing signal distortion and possible data errors. Therefore, breaking ground loops through galvanic isolation not only prevents loop currents, but also presents the most reliable method of dealing with high ground potential differences.
- No news
- EE Times Silicon 60: Hot Startups to Watch
- Silicon 60 Reveals Shifts in Technology Focus
- CEO interview: China, not Apple, is way to go, says mCube CEO
- Cirrus to take half audio codec and hub IC market, says report
- Is there still room for the vacuum tube?
- Top ten MEMS microphone vendors ranked
- More wafer fab closures expected in 2014, says IC Insights
- EMC regulations face major shake-up
- Magnetic position sensors perform compensation on chip
- Top ten automotive MEMS sensor vendors ranked
- Bosch reduces size, power of 6-axis IMU
- The self-powered Interent of Things is starting up
- When GND isn't GND single-ended circuits become differential
- Researchers discover how beryllium causes deadly lung disease
- Mapper opens Russian MEMS fab
- Automated Macro-Model Extraction Using SPICE Netlist
- Dual 13A μModule Regulator with Digital Interface for Remote Monitoring & Control of Power
- Localized Haptic Feedback for Touch Controls
- Flexible and Low Power Driving of Solenoid Coils
- Precision Industrial Systems Demand a New Level of Data Conversion Accuracy
- 14-Bit, 4-20 mA, Loop Powered, Thermocouple Temperature Measurement System Using ARM Cortex-M3
- High-Precision Sine/Cosine Interpolation