Methods of isolation

ICs are the basic building blocks used to achieve isolation in modern high-voltage systems because they can block DC and low-frequency AC currents while allowing power, analog signals or high-speed digital signals to transfer across the barrier. Figure 4 shows three popular semiconductor technologies: optical (optocoupler), electric field signal transfer (capacitive) and magnetic field coupling (transformer). TI isolation ICs use both advanced capacitive isolation technology and proprietary integrated planar transformers. TI leverages its position in package development, isolation and process technology to achieve some of the highest levels of integration, performance and reliability.

Each technology relies on one or more semiconductor insulating materials, such as those listed in Table 3, to achieve the required level of isolation performance. Higher dielectric strength materials are more effective for isolating similar voltages over a given distance.