PF5030 read I2C while all output lost

[Pony_Ma]

Hi, when a fatal error occurs, all outputs of the PF5030 are lost while the input power remains present. Is there any way to retrieve detailed fault information via I2C?

The VDDIO is supplied from one of its outputs. In this situation, VDDIO is lost, so the I2C interface may not function. But what if I provide an external VDDIO after the fatal error occurs?

Will the error message still be retained or will it already be lost? Can I retrieve the error reason by supplying external VDDIO after the error happened and attempting I2C communication?

[JozefKozon · Accepted solution]

Hi Pony,

• When a fatal error occurs (e.g., watchdog failure, overvoltage on monitored rails, or fault counter overflow), the PF5030 transitions into DEEP-FS state.
• In DEEP-FS, all regulators are turned off. 
• The fail-safe logic remains powered internally from VIN
• The I²C interface is in the fail-safe domain and becomes functional again once VDDIO is present (1.71 V to 5.25 V range).
• as long as VIN remains above the POR threshold and the device has not been power-cycled, the fail-safe registers (e.g., FS_GRL_FLAGS, FS_OVUVREG_STATUS1, FS_DIAG_SAFETY, FS_STATES) will still contain:
  • Which voltage monitor triggered (OV/UV flags)
  • Watchdog error flags
  • Fault counters and state machine status
• These registers are cleared only by POR or explicit writes, not by entering DEEP-FS

• FS_GRL_FLAGS (general fault summary)
• FS_OVUVREG_STATUS1 (which VMON triggered)
• FS_DIAG_SAFETY (watchdog, CRC, BIST status)
• FS_STATES (current fail-safe state)

You can recover detailed fault information after a fatal error by externally powering VDDIO, provided VIN was never lost. If VIN drops below POR, all volatile registers are cleared.

With Best Regards,

Jozef