Safety-critical automotive systems, such as electric power steering (EPS) and braking, are required to meet the requirements of ASIL-D, which is the highest automotive safety integrity level prescribed in the ISO 26262 functional safety standards.
The IC integrates a number of failure detection functions including: high-voltage and low-voltage detection and overheat detection of power supply circuit to monitor against the IC’s own failure, as well as a watchdog timer to monitor failure detection of the external MCU.
An initial diagnosis circuit to detect latent faults in the failure detection circuits is also incorporated to secure higher functional safety.
The IC generates a 6V output from a high efficiency buck-boost DC-DC converter. In order to avoid problems following a voltage drop during cranking, the low side operating voltage range is improved down to 2.7V (min.) with battery operation.
Toshiba has carried out a range of functional safety analyses to simulate system failures and will provide customers with documentation, such as functional safety FMEDA, to support overall safety analysis and design.
The IC incorporates four series power supply output circuits receiving the 6V input generated by the DC-DC converter. It also incorporates an output circuit with a 5V constant voltage (current capacity is 400mA) for the microcomputer, and three circuits with 5V constant voltage output (current capacity is 100mA) for sensors and other interfaces. Each of them can output a voltage independently.
Mass production scheduled to start in October 2017.
