7 Isolated Power and Data Into Single Device

The Texas Instruments ISOW7841 is part of a family of reinforced quad-channel high-performance digital isolators that integrate a high-efficiency, low-emissions DC/DC converter. The digital isolators operate up to 100-Mbps, with a propagation delay less than 16-ns. The integrated DC/DC switch-mode converter uses advanced circuit techniques to reduce power losses and boost efficiency, supporting 130-mA of load current with 5-V input and 75-mA of load current with 3.3-V input. Integrated closed-loop feedback provides excellent line and load regulation. Special emissions-reduction techniques have been implemented to help meet emissions standards.

However, designers lose some flexibility with integrated power and data solutions, for instance, configuration for the number of outputs, and isolation levels.

For a high-level block diagram comparison of three solutions, see Figure 7-1.

• SN6505 based open-loop push-pull power supply with separate digital isolator
• Integrated power module UCC12050 with separate digital isolator
• ISOW7841 with integrated digital isolators

Figure 7-1 Comparing Discrete and Integrated Solutions

For all the three approaches shown in Figure 7-1, the layout comparison is highlighted in Figure 7-2. The integrated solutions show how overall size can be reduced.

Figure 7-2 Layout Size Comparison for (A) SN6505 + Digital Isolator (B) UCC12050 + Digital Isolator (on bottom layer) and (C) ISOW7841