STi²Fuse, wire protection, control and diagnostics for each channel
Wire weight 20%↓·Size 25%↓ compared to existing relay fuses

STMicroelectronics (ST) has introduced an electronic fuse with the i²t algorithm and CCM (Capacitive Charging Mode) function to cope with the rapidly increasing number of ECUs due to the transition to electric and autonomous vehicles.

On the 26th, ST Vice President Youngmin Choi hosted a webinar on e4ds news with the topic of 'ST Smart Fuse for Automotive Power Distribution (STi²Fuse)', and presented ST's electronic fuse as a solution to the challenging power distribution method in the automotive market that has adopted a centralized architecture (Zonal Architecture).

Vice President Choi said, “STi2Fuse is a switch and fuse that supplies power to various ECUs and distributes power in vehicles through a variety of product lines that cover 1.5 to 450A,” and explained, “STi²Fuse is an electronic fuse that adds the i²t algorithm and CCM (Capacitive Charging Mode) function to the existing HSD product, satisfying demanding requirements.”

As the automobile industry trend shifts from internal combustion engines to electric and autonomous vehicles,The number of ECUs (Electronic Control Units) being used is rapidly increasing, and as a result, wiring between ECUs is becoming more complex.

To solve these problems, global automakers are considering a centralized architecture (Zonal Architecture).

This architecture simplifies the wiring harness and significantly reduces weight because each ECU is physically close to the vehicle.

In addition, since all ECUs can be managed and supervised centrally, system maintenance and repair through software updates are easy.

On the other hand, the power distribution method using the existing relay and fuse configuration does not satisfy various requirements (individual output control, status diagnosis, current/voltage/temperature monitoring) to maximize the above performance.

ADAS applications that are directly related to safety must be designed for high availability to ensure normal operation even in the event of a failure, and in the primary power distribution stage, a fast shutdown speed of 100 to 500 ms is required when an overcurrent occurs so that the power line can always maintain a stable voltage.

The existing fuse configuration has a slow tripping speed of less than 50ms, so it is necessary to switch to an electronic fuse to meet the requirements.

STi²Fuse not only protects wires with the i²t algorithm, but also enables control and diagnosis for each channel, which has the advantage of allowing the omission of the existing secondary power distribution stage.

Also, useIt is possible to block by self-set i²t curve, and it helps improve fuel efficiency by reducing weight due to wire by about 20%. It is also about 25% lighter and can be designed in a smaller size compared to existing relay fuse configurations.

If 48V HSDs are adopted instead of the existing 12V system, the weight of the wiring harness can be reduced to one-quarter, large-capacity loads can be easily covered, and in the case of DC motors, they can be designed to be lighter and smaller for the same power when using 48V.

ST is combining these advantages to prepare a family of STi²Fuse fuse products and 48V HSDs drivers.

ST is preparing a variety of STi² products, including a Monolithic family designed to target zonal boxes for low currents from 1.5 to 15 A, and a Power QFN package for power distribution boxes for medium currents from 6 to 45 A.

“We are also preparing an Excel tool for each product to enable easier review when using the STi²Fuse product line,” said ST Vice President Youngmin Choi. “Using this tool, you will be able to easily find the optimal wire square through a few setting parameter values.”

For more information on the above electronic fuse trends, including detailed information on ST's STi²Fuse, please see the 'Smart Fuse for Automotive Power Distribution (STi2Fuse) Webinar' on the e4ds webinar page, where you can also download the presentation materials.