Why isolation matters for your power electronics

Innovations in isolation pave the way for more sophisticated electric vehicles, more intelligent factory sensors and robots, and more reliable medical devices

30 Aug 2022

Inside every high-voltage technology story, there’s a good chance you’ll find an unsung innovation in isolation behind the scenes.

Isolation – an important foundational technology that’s embedded in everything from electric vehicles (EVs) to automated factory equipment and medical devices – rarely makes headlines. That’s by design. 

“We don’t want people to hear about isolation,” said Pradeep Shenoy, who leads our company’s automotive power design team. “If isolation is in the news, it means there’s been a problem."

Keeping circuits isolated is an important design element for equipment with both alternating current (AC) and direct current (DC) power sources. That’s especially true for circuits that rely on high voltage. When isolation is not properly implemented, electromagnetic interference, electrical damage, short circuits, fire or shock can occur. 

“How you implement isolation is important because it will impact other parts of the system, affecting electromagnetic interference, efficiency and space,” Pradeep said. “And those noisy disturbances can interrupt data transmission or interrupt motors, which are major examples of why you use isolation.”

Tackling evolving isolation challenges

Isolation is becoming a more common challenge now that people come in contact with a wider variety of high-voltage applications, such as electric vehicles that run on 400- or 800-volt battery packs. The systems that manage these batteries and communicate with the rest of the vehicle require isolation components, which can increase the size, weight and cost of a vehicle. And as personal electronics become more sophisticated and miniaturized, the risk of electromagnetic interference – an undesirable byproduct of switching currents and voltages – rises as well.

To help engineers eliminate components from their designs and reduce solution size and cost, our company’s new solid-state relays integrate power and signal transfer on a single chip, with enough capacity to support the power needs of next-generation EVs, grid infrastructure, industrial robots and more. The significant integration in these chips can fit into just one-tenth the space required for traditional isolation components.

“Without integration, you need an external transformer to handle isolation, and those parts can add bulk and complexity to the design," said Robert Taylor, who leads our company’s industrial power design services team. “It adds reliability when everything is self-contained."

Some conventional isolation designs use physical relays whose moving parts make them susceptible to failure in adverse conditions, such as extreme heat, cold or vibration. Solid-state relays with integrated power and signal isolation don’t have moving parts that will wear out over time and therefore have up to 10 times the expected lifespan of a relay.

Our company is also one of few manufacturers to integrate magnetic isolation into solid-state devices and the only company with ongoing investment in both magnetic and capacitive isolation. Our advancements in capacitive and magnetic isolation, package development, and process technology deliver power and high-speed signals safely and reliably across the isolation barrier in industrial and automotive systems such as EVs, grid infrastructure, factory automation and motor drives.

“High voltage is critical for transferring power efficiently and cost-effectively, and isolation is crucial for safety anywhere you have high voltage,” said Jeff Morroni, director of power management for Kilby Labs, our company’s corporate research-and-development group. “For example, in battery management and other systems in EVs, we need to prevent shock by ensuring high voltages don’t make it to the chassis. As isolation needs evolve, we continue to look for innovative ways to keep people and the high-voltage systems they interact with safe.” 

Isolation in practice

To better understand the importance of isolation, consider the role it plays in some of today’s key markets.

Electric vehicles: EVs have a high-voltage battery – typically 400 or 800 volts – to provide propulsion and a conventional lower-voltage battery for cabin conveniences and infotainment. Isolation plays a dual role as protector and performance booster. 

“Isolation in EVs helps protect the driver when you turn off the car, but it also plays an important role in making EV batteries last as long as they can," Pradeep said. “Isolation allows the systems that supervise, monitor and protect the battery cells to safely and accurately communicate back to the central microcontroller, which operates at a different voltage.”  

Industrial automation: Improvements in isolation technology can provide protection from high-voltage surges that may damage equipment or harm humans. It can also shield automated devices such as sensors, motors, robots and other equipment from signal interference so they can operate reliably. “Isolation technology protects power, communications and control – the functions that enable intelligent automation throughout the factory floor and improve efficiency, productivity and safety,” Robert said. “But the most important function is safety and to protect the end user.”

Solar and smart grid: Anywhere you find power generation and transmission, you need some isolation technology. This includes home solar panels that convert solar energy to electricity for the grid.

“High voltage from solar panels needs to be isolated and then converted to AC current, where the voltage will need to be stepped down as it goes through the grid,” Robert said. “Each time we step it down – from high voltage to the mid-voltage that goes into the transformer outside your house – there is a different layer of isolation needed so it can be done safely.”

Medical devices: Cost reduction is always a priority in healthcare. The reduced size and complexity of solid-state isolation devices make it possible for designers to develop smaller circuits without sacrificing safety or features. The higher reliability of modern solid-state isolation supports the requirement for high uptime and low failure rates in healthcare.

“At TI, we’ve been developing isolation technologies in integrated circuits for high-voltage systems for two decades,” Jeff said. “We’re continuing to find new ways to make isolation better, enabling engineers to reduce complexity and maintain safety in power-supply systems.”

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