An IPD is a power IC device that integrates in a single package control circuits that implement protection functions and self-diagnostic functions, in addition to power MOSFET (metal–oxide–semiconductor field-effect transistor) switching element(s). The IPDs are compact, lightweight, power efficient, and not subject to the contact wear and tear that affects mechanical relays, enabling highly reliable systems with self-protection functions.

Previously, most ECUs used relays as the switching elements in their drive circuits, with the average automobile using around 100 relays. The transition from mechanical relays to semiconductor switching began in applications like lighting control, and the trend is expanding to other automotive systems, such as motor and heater control, driving demand for highly reliable and high-performance semiconductor switching devices.

Recently, stricter environmental regulations in Japan and other countries have spurred accelerated efforts to improve fuel efficiency. This has heightened the need to address demands for reduced vehicle weight, more compact and lighter ECU, and low power consumption.

However, creating lightweight vehicles has been made difficult as routing of the wire harness is determined and the configuration location is being restricted due to the mechanical relay maintenance in the relay box -or referred as junction box- that is responsible for power distribution within the vehicle, and in which many of the mechanical relays are housed.

This has led to the growing demand to free placement constrains in the relay box and to allow greater flexibility of the wire harness routing by configuring the relay box with a semiconductor switch with self-protection function.

However, conventional semiconductor switches have been unsuitable for handling large currency, which has impeded efforts to develop semiconductor-based replay boxes previously. Therefore, it is difficult to deal with high current loads when using conventional semiconductor switches.

For many years, Renesas has delivered IPDs for automotive body applications that contribute to the compactness/lightweight, higher performance and reduced power consumption of ECUs. Renesas has leveraged its long-time experience and expertise to deliver new IPDs achieving low on-resistance and high breakdown tolerance that support large current applications.