MinebeaMitsumi Inc.’s group company, ABLIC, has introduced the S-19193 Series of vehicle 3 to 6-cell battery monitoring protection integrated circuits. Battery management systems (BMS) for electric cars (EVs), e-bikes, and other similar devices must adhere to ISO26262, a standard for functional safety in road vehicles.
The ability to return to a safe state in the event of a failure or malfunction, the ability to continue operating even in the event of a failure or malfunction, and the ability to continue operating with reduced functionality are the acceptance criteria for functional safety. The traditional approach to attaining (1) fail-safe functional safety in the past involved monitoring automotive battery overcharge and overdischarge conditions using a microcontroller (MCU) in conjunction with a high-performance integrated circuit known as a “analog front-end” (AFE).
According to the traditional fail-safe methodology, a driver’s safety is guaranteed by “returning to a safe state,” which means stopping the car in the event of a real failure or malfunction. After the car has safely stopped, there is no need to keep an eye on the batteries.
However, as automated driving technologies advance, it is anticipated that more situations will arise in which the system, not the driver, resolves issues. For this reason, fail-operational and fail-degraded methodologies—which enable continued operation even in the event of a failure or malfunction—are becoming more and more crucial.
With features for tracking vehicle battery overcharge and overdischarge, the S-19193 Series automotive 3 to 6 cell battery monitoring protection ICs were introduced. These devices were created using procedures that comply with ISO26262.
Examples of AFE and MCU internal monitoring functions set up as primary and secondary are also available; however, these are primarily used for fault and failure detection through mutual monitoring and are not adequate for functionality backup. Internal redundancy also increases the risk of “joint failure,” which is when a failure occurs and functionality is lost at the same time. The S-19193 Series allows for the complete separation of secondary monitoring from primary monitoring, which further reduces the possibility of joint failures.
Additionally, the S-19193 Series allows for the configuration of a secondary monitoring circuit that can operate independently without the need for MCU control, potentially reducing the number of design steps.
Additionally, a Safety Manual that supports BMS functional safety design with the S-19193 Series can be downloaded. Additionally, the product complies with the U.S. Automotive Industry Action Group’s (AIAG) Production Part Approval Process (PPAP).
