TOKYO—Toshiba Electronic Devices & Storage Corporation (“Toshiba”) today announced the launch of “TB9045FNG,” a general-purpose system power IC with multiple outputs achieving functional safety[1] for automotive applications. The new IC is available in four versions, with output voltages ranging from 1.1V to 1.5V. Mass production is scheduled to start this month.
More and more safety-critical automotive systems, such as electric power steering (EPS) and braking, are required to meet the requirements of ASIL-D[2], the highest automotive safety integrity level prescribed in the ISO 26262 functional safety standards.
The new IC integrates various failure detection functions, such as high-voltage and low-voltage detection, overheat detection, and frequency monitoring of power supply circuit, to monitor against the IC’s own failure, and a watchdog timer to monitor failure detection of the external microcontroller. An initial diagnosis circuit to detect latent faults in the failure detection circuits is also incorporated to secure higher functional safety.
Toshiba has also carried out a range of functional safety analyses to simulate system failures and will provide customers with documentation, such as functional safety FMEDA[3], to support overall safety analysis and design.
Main Features
1. Built-in buck-boost DC-DC converter
The IC generates 6V output from a high efficiency buck-boost DC-DC converter.
In consideration of voltage drop after idling reduction, the low side operating voltage range is improved down to 2.7V (min.) with battery operation.
2. Built-in buck DC-DC converter (Voltage selectable)
The 6V input power generated by the buck-boost DC-DC converter is converted to output voltages of 1.1V (TB9045FNG-110), 1.2V (TB9045FNG-120), 1.25V (TB9045FNG-125), and 1.5V (TB9045FNG-150). The appropriate version of the new IC can be used as an external power supply for a core, based on the MCU specifications.
3．Built-in 4 series power supply[4] circuits (4 outputs)
The IC incorporates four series power supply circuits receiving the 6V input generated by the DC-DC converter. It also incorporates a circuit with a 5V constant voltage (current capacity is 400mA) for the microcontroller, 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.
4. Various built-in monitoring circuits for functional safety
Low-voltage detection circuit for battery power supply
High-voltage detection circuit for DC-DC converter (6V)
High-voltage / low-voltage detection circuits for the DC-DC converter (1.1V/1.2V/1.25V/1.5V) and series power supply (5V)
Overheat detection circuit
Oscillator frequency monitoring circuit
Watchdog timer circuit monitoring the external MCU
5. Diagnostic circuit for failure detection circuits for functional safety
A built-in diagnostic circuit in the failure detection circuit detects any latent faults.
6. Selectable operation for failure detections
Customers can set the system to respond to detected failures in one of two ways, using the SPI[5] communication input setting. One setting outputs a reset signal to the system; the other provides notification of the abnormal operation to the system. Selection can be made according to the customer’s application or system.
