Using integrated drivers to deliver functional safety in automotive motor control?

Using integrated drivers to deliver functional safety in automotive motor control?

More and more automotive applications now employ motors for enhanced automation – in areas such as locking mechanisms, mirror adjustment and parking, cooling fans and so on. And while problems with these systems would be a nuisance, in most cases they would not have a significant impact on safety.

However, motors are also used in safety critical automotive applications. As an example, to move the throttle body, to control the power steering or to position the driver’s seat. Unexpected or uncontrolled operation of any of these would have potentially catastrophic consequences to a vehicle in motion.

While there are many layers of safety standards and design philosophies in automotive circles, culminating in the all-encompassing ASIL standard, modern integrated motor drivers are increasingly incorporating self-checks that would have previously necessitated a microcontroller.

As an example, the forthcoming TB9051FTG integrated motor driver IC from Toshiba runs a power-on diagnostic test that checks the supply voltages to the control logic as well as to the motor itself. Out-of-specification voltages can create the type of erratic behaviour we have to avoid in safety-critical applications.

This brief (80μs) test runs automatically each time the IC is powered – and can be run again and again by toggling the enable pin during a restart.

Alongside other safety checks, such as detecting high-impedance states on key control signals that might indicate a broken wire, this simple check is just one of the ways that Toshiba’s advanced motor drivers are ensuring safety in modern automotive applications. To learn how these drivers can make you designs simpler and safer, please click here:

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