The PMIC incorporates MCU monitoring functions, such as a watchdog (Q&A or trigger) timer, error signal monitoring, and diagnostics using SPI, GPIO, and I2C interfaces. The complexity of communication from the PMIC to the MCU often leads the designer of the traction inverter to select both sockets from a single vendor. However, TI has set up a range of safety PMICs that also support MCUs of competitors while enabling the required functional safety rating. This additional support increases the flexibility of a design.

For the traction inverter use-case, TI proposes the TPS653860-Q1 and TPS653861-Q1 PMIC devices featuring the following power outputs:

• Pre-regulator (buck-boost converter) with 6V, 5V, or 4.3V output at 1.5A (version 1) or 2.8A (version 0)
• Protected LDOs (PLDOs) 1 + 2 against shorts to VBAT and GND up to 200mA at 1.xV, 2.5V, 3V, 3.3V, and 5V
• LDOs 1 + 2 with a bypass mode for 600mA at 1.0V – 1.8V, 3.3V, and 5.0V
• LDOs 3 + 4 with a bypass mode for 200mA at 1.0V – 1.8V, 3.3V, and 5.0V at 1%

See Figure 4-2 for a typical application diagram. With a maximum input voltage of 36V, a pre-regulator device is required in vehicles with a 48V battery. A setup like this is observed for multiple applications within the vehicle architecture dealing with the step to 48V.

Figure 4-2 Typical Application Diagram for TPS65386x-Q1 PMIC