David Krakauer
Analog Devices

For designers of isolated systems, rapid advances in digital isolation technology are yielding new capabilities that greatly simplify their job. Examples include integrated, isolated power and truly bidirectional isolation channels that can reduce system costs and save circuit-board real estate. These advances are fueled by a shift away from LED-based optocouplers toward newer isolator technologies that are compatible with standard foundry CMOS processes. They enable integrated circuitry to be packaged with chip-scale microtransformers, thus fitting more functionality into a single package.

This article discusses two kinds of devices that embody these advances. In the first example, isolated power, chip-scale microtransformers are complemented by switches, rectifiers, and regulators to produce an isolated, regulated dc-to-dc converter; when integrated with isolated data channels it provides a complete isolation solution. In the second example, bidirectional isolation, integrating the requisite buffers and drivers creates an isolator that has truly bidirectional isolation channels without the need for external signal conditioning.