Multi-rail power supply for safety-relevant applications and the automotive industry

08-04-2020 | Texas Instruments | Power

Texas Instruments TPS653851A-Q1 Multi-Rail Power Supply is intended to supply microcontrollers in safety-relevant applications, including those encountered in the automotive industry. The device supports functional safety microcontrollers with dual-core lockstep and other multi-core architectures. The device combines multiple supply rails to power the MCU, CAN or FlexRay, and external sensors. A buck-boost converter, with internal FETs, converts the input battery voltage between 2.3V and 36V to a 6V pre-regulator output supplying the other regulators. An integrated charge pump gives an overdrive voltage for the internal regulators and can also be employed to drive an external NMOS FET as reverse battery protection. The device supports wake-up from an IGN pin or wake-up from a CAN transceiver or other signal (CAN_WU pin).

An independent voltage monitoring unit inside the device monitors undervoltage and overvoltage on all internal supply rails and regulator outputs of the battery supply. Regulator current limits and temperature protections are also performed. The device highlights a question-answer watchdog, MCU error-signal monitor, clock monitoring on the internal oscillator, self-check on clock monitor, CRC on non-volatile memory and SPI communication. It also provides a diagnostic output pin enabling MCU to observe device internal analog and digital signals, a reset circuit for the MCU (NRES pin), and a safety output (ENDRV pin) to disable external power-stages on any detected system-failure. The device automatically operates a BIST at startup, and the MCU may re-run the BIST through system run time through software control if required. A dedicated DIAGNOSTIC state allows the MCU to check the device functionality.

The device also offers an error reporting ability through the SPI register. The device has separate status bits in the SPI register for each distinct error on the system level or device level. When the device identifies a particular error condition, it sets the relevant status bit and maintains this status bit set until the MCU reads-out the SPI register in which this status bit was set. Based on which status bit was set, the MCU can determine whether it must retain the system in a safe state or whether it can continue the operation of the system. The devices are AEC-Q100 qualified for automotive applications.

The devices are ideal for automotive safety-relevant applications, and industrial safety-relevant applications.

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