Toshiba Electronics Europe has announced the launch of TB9057FG, a brushed motor pre-driver IC that provides enhanced functional safety and control for automotive applications such as electric power steering systems (EPS). The new IC meets the requirements set in Automotive Safety Integrity Level D (ASIL-D).
Increasing numbers of safety-critical automotive systems are required to meet the requirements of ASIL-D standards. These are the most stringent automotive safety integrity levels prescribed by ISO 26262, “Road Vehicles – Functional Safety.”
The new IC integrates a pre-driver circuit, dual motor current detection circuit that converts motor current to voltage and output to MCU, It also integrates motor direction detection circuitry that detects whether external MOSFETs turn on or off normally and output the direction information to MCU.
Various failure detection circuits such as VB under voltage detection circuit, VDD under voltage detection circuit, over temperature detection circuit, and short circuit detection circuitry that detects any short circuit between the drain and source of a driver (MOSFET) are also integrated into the IC. Additionally, functions including motor current detection circuit, power supply PIN, and GND PIN are made redundant to secure higher robustness.
In order to accommodate the possibility of a voltage drop caused by cranking after idling reduction, the battery operation voltage range has been reduced to 5V (min.) compared to the 6V (min.) of the predecessor product.
The built-in motor current detection circuit and motor direction detection circuit simplifies system design and reduces PCB size.
Customers can set the system to respond to detected failures in one of two ways, using the input setting of the SEL pin. One setting uses this new IC to stop the external MOSFET, the other switches to external control of the MOSFET using the MCU. Selection can be made according to the customer’s application or system, and reduces loads on the MCU.
Toshiba has also carried out a range of functional safety analyses to simulate various system failures and will provide customers with documentation to support safety analysis and design.
Housed in a LQFP48-P-0707-0.50C package measuring 9.0mm by 9.0mm by 1.6mm, the IC supports an operating voltage range of +5 to 21V and has an operating temperature range of -40°C to 125°C.