SLLA651 April   2025 TCAN2845-Q1 , TCAN2847-Q1 , TCAN2855-Q1 , TCAN2857-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Device States
    1. 2.1 Init Mode
    2. 2.2 Restart Mode
    3. 2.3 Standby Mode
    4. 2.4 Normal Mode
    5. 2.5 Sleep Mode
    6. 2.6 Fail-Safe Mode
  6. 3Power Electronics
    1. 3.1 VSUP
    2. 3.2 VHSS
    3. 3.3 VCAN
    4. 3.4 VCC1
    5. 3.5 VCC2
    6. 3.6 VEXMON, VEXCTRL, and VEXCC
    7. 3.7 HSSx
  7. 4Communication Capabilities
    1. 4.1 CAN-FD and Classical CAN
    2. 4.2 CAN-SIC
    3. 4.3 LIN
  8. 5Protection Features
    1. 5.1 Undervoltage (UV) Monitors
      1. 5.1.1 VSUP
      2. 5.1.2 VHSS
      3. 5.1.3 VCAN
      4. 5.1.4 VEXCC
      5. 5.1.5 VCC1
      6. 5.1.6 VCC2
    2. 5.2 Overvoltage (OV) Monitors
      1. 5.2.1 HSSx
      2. 5.2.2 VCC1
      3. 5.2.3 VCC2
      4. 5.2.4 VEXCC
    3. 5.3 Short Circuit (SC) Monitors
      1. 5.3.1 VCC1
      2. 5.3.2 VCC2
      3. 5.3.3 VEXCC
    4. 5.4 Electrical Faults and Impact on SBC Mode
    5. 5.5 Temperature Sensors
    6. 5.6 Watchdog
      1. 5.6.1 Watchdog Error Counter
      2. 5.6.2 Timeout
      3. 5.6.3 Window
      4. 5.6.4 Initial Long Window
      5. 5.6.5 Q&A
    7. 5.7 Communication Fault Monitoring
      1. 5.7.1 CAN
      2. 5.7.2 LIN
    8. 5.8 LIMP
  9. 6Programming, Memory, and Control
    1. 6.1 SPI
    2. 6.2 EEPROM
    3. 6.3 Interrupts
    4. 6.4 Control
  10. 7Miscellaneous Features
    1. 7.1 Local Wake Ups
    2. 7.2 CAN Bus Wake Up (BWRR)
    3. 7.3 Partial Networking
    4. 7.4 GFO, nRST, and SW
  11. 8Summary
  12. 9References

3.4 VCC1

VCC1 is the primary LDO of the SBC that does not only provide an external power output but also is used to bias internal subsystems such as portions of the communication network and the SPI communication. VCC1’s value is set based on the part number used – if the device has the pattern TCAN28xx5 the output is 5V and the logic pins of the device are referred to 5V and if the device part number has the pattern TCAN28xx3 the output is set to 3.3V with the logic pins referenced to 3.3V.

VCC1 can output up to 250mA of regulated output current that can be used to power external peripherals. A common use case of VCC1 is to power the controller of the SBC with the VCC1 voltage to eliminate the need for a discrete step-down regulator to power this controller. Other common options are providing biasing voltages for ADC inputs or other sensors (such as hall effect sensors).

VCC1, since this acts as the primary LDO for the TCAN28xx devices, also has a strong influence on the device state. Undervoltage events on VCC1 can result in the device transitioning to restart mode to try to bring VCC1 back to proper level or else this can transition to sleep or fail-safe (if enabled). Other fault conditions like OVCC1 and VCC1_SC can result in the device entering sleep or fail-safe (if enabled). The VCC1 LDO also has a temperature sensor that monitors the VCC1 LDO temperature and if a thermal fault is detected the device can transition to sleep or fail-safe mode. This LDO does act differently as faults on the other power electronics of the device do not result in mode changes, but on VCC1 there are mode changes. This is critical in any application that uses these devices that each VCC1 fault scenario is adequately mapped out at a system level to make sure the system can respond appropriately to VCC1 faults.