Photocoupler Enables High-Voltage Automotive SSR Design

Toshiba Electronic Devices & Storage Corporation has released the TLX9920, a photovoltaic-output photocoupler designed for solid state relays (SSR) in automotive and high-voltage applications. The device supports reliable switching in systems where long service life, electrical isolation, and reduced maintenance are critical.

Transition from Mechanical Relays to SSR
Automotive relay systems are increasingly shifting from mechanical relays to SSR due to durability and reliability requirements. Unlike mechanical relays, SSR operate without physical contacts, eliminating wear-related failures and reducing maintenance needs.

The TLX9920 is designed as a gate driver for high-voltage power MOSFETs used in SSR architectures. This configuration enables high-voltage and high-current switching performance that is typically not achievable with conventional photorelays, supporting the growing demand for robust switching in electrified vehicle systems.

Electrical Performance and Isolation Design
The device is housed in a thin SO6L package featuring a creepage distance exceeding 8 mm. This design supports a high isolation voltage of 5000 Vrms, enabling safe operation in high-voltage environments.

The creepage distance exceeds the requirements defined in IEC 60664-1 for pollution degree 2 environments operating at 400 V or higher, which specify a minimum of 5.6 mm. This margin enhances insulation reliability in applications exposed to electrical stress and environmental contamination.

Compliance and Reliability Standards
The TLX9920 complies with AEC-Q101, a key automotive reliability standard for discrete semiconductor components. This certification indicates that the device meets stringent requirements for thermal cycling, mechanical stress, and long-term operational stability in automotive environments.

Such compliance is essential for integration into safety-critical systems, including battery management, onboard power distribution, and high-voltage switching modules.

Application Scope Across Power Systems
The photocoupler is suitable for a range of switching applications beyond automotive systems, including energy storage systems (ESS) and industrial power equipment. In these contexts, high isolation voltage and stable switching performance are required to ensure system safety and efficiency.

By enabling reliable MOSFET control in SSR configurations, the TLX9920 supports compact, maintenance-free switching solutions in high-voltage architectures.

Relevance for Electrified and Data-Driven Systems
As electrification expands across automotive and industrial sectors, components that ensure reliable power control and isolation become increasingly critical. Devices such as photovoltaic-output photocouplers contribute to system resilience by supporting efficient switching and reducing failure points.

Within a broader digital supply chain and automotive data ecosystem, these components enable the development of more durable, high-performance electronic systems capable of meeting evolving operational and safety requirements.

Edited by Romila DSilva, Induportals editor, with AI assistance.