SLVA528D September   2012  – August 2021 TPS65381-Q1 , TPS65381A-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Product Overview
    1. 2.1 Safety Functions and Diagnostics Overview
    2. 2.2 Target Applications
    3. 2.3 Product Safety Constraints
  4. 3Development Process for Management of Systematic Faults
    1. 3.1 TI New-Product Development Process
  5. 4TPS65381x-Q1 Product Architecture for Management of Random Faults
    1. 4.1 Device Operating States
    2.     Device Operating States (continued)
    3. 4.2 NRES (MCU Reset) Driver and ENDRV (SAFING Path Enable) Driver
  6. 5TPS65381x-Q1 Architecture Safety Mechanisms and Assumptions of Use
    1. 5.1 Power Supply
    2. 5.2 Regulated Supplies
      1. 5.2.1 VDD6 Buck Switch-Mode Supply
      2. 5.2.2 VDD5 Linear Supply
      3. 5.2.3 VDD3/5 Linear Supply
      4. 5.2.4 VDD1 Linear Supply
      5. 5.2.5 VSOUT1 Linear Supply
      6. 5.2.6 Charge Pump
    3. 5.3 Diagnostic, Monitoring, and Protection Functions
      1. 5.3.1 External MCU Fault Detection and Management
        1. 5.3.1.1 External MCU Error Signal Monitor (MCU ESM)
        2. 5.3.1.2 Watchdog Timer
      2. 5.3.2 Voltage Monitor (VMON)
      3. 5.3.3 Loss-of-Clock Monitor (LCMON)
      4. 5.3.4 Junction Temperature Monitoring and Current Limiting
      5. 5.3.5 Analog and Digital MUX (AMUX and DMUX) and Diagnostic Output Pin (DIAG_OUT)
      6. 5.3.6 Analog Built-In Self-Test (ABIST)
      7. 5.3.7 Logic Built-In Self-Test (LBIST)
      8. 5.3.8 Device Configuration Register Protection
  7. 6Application Diagrams
    1. 6.1 TPS65381x-Q1 With TMS570
    2. 6.2 TPS65381x-Q1 With C2000
    3. 6.3 TPS65381x-Q1 With TMS470
  8. 7TPS65381x-Q1 as Safety Element out of Context (SEooC)
    1. 7.1 TPS65381x-Q1 Used in an EV/HEV Inverter System
    2. 7.2 SPI Note
  9. 8Revision History

5.3.2 Voltage Monitor (VMON)

A voltage-monitor module (VMON) supervises the VBATP supply voltage, and all regulator outputs and internally generated voltages. The corresponding VMON register status flag bits indicate an undervoltage (UV) or overvoltage (OV) condition:

  • VMON flag bit set to 0 when the regulator (voltage rail) is within specification
  • VMON flag bit set to 1 when the regulator (voltage rail) is outside tolerance band

Undervoltage and overvoltage comparators perform the monitoring. The reference voltage (BANDGAP_REF2) for the VMON module is independent of the system reference voltage (BANDGAP_REF1) used by regulators.

A glitch-filtering function (deglitch) ensures reliable monitoring without false setting of the VMON status flag bits. A separate supply pin, VBAT_SAFING, supplies the complete VMON block.

Analog built-in self-test (ABIST) covers VMON comparator diagnostics, executed during device power up from STANDBY state. It may also be activated by the MCU though a SPI request when the device is in the DIAGNOSTIC or ACTIVE state. Emulation of each monitored voltage rail for an undervoltage and overvoltage condition on the corresponding comparator inputs forces the corresponding comparator to toggle multiple times (in a toggling pattern observed and checked by ABIST controller).

GUID-8C2A5C32-72F9-44E1-8ED1-2F0B42FEBC45-low.gif
Monitoring of the sensor-supply output voltage occurs within the sensor supply itself using BG1 as a reference.
The BG1 error is caught by VMON using VMON BG as a reference.
Figure 5-6 Voltage Monitoring