SW1 RUN VOLT Values Not Reflected on SW1LX Pin in PF5020

[Shivani_Elavena]

hi,

I hope this message finds you well.

We are currently working with the PF5020 SW1 regulator, and we have encountered an issue. writing and reading to the SW1 RUN VOLT register is working but, the values do not appear to be reflected on the SW1LX pin as expected.

Could you please provide guidance on why this might be happening or suggest any troubleshooting steps we should follow to resolve this issue?

Thank you very much for your support. Looking forward to your response.

Best regards,
[Shivani]

[TomasVaverka]

Hi,

Please see below several possible causes:

- Regulator disabled due to fault: The PF5020 monitors undervoltage (UV), overvoltage (OV) and current limit (ILIM) conditions. If any fault is detected and the corresponding fault state bit (SW1_UV_STATE, SW1_OV_STATE or SW1_ILIM_STATE) is set to disable the regulator, it will shut down even if the RUN VOLT register is correctly configured.

- EN1 pin not asserted: The EN1 pin must be high to enable SW1. If it is low, SW1 will remain off regardless of register settings. 

- Incorrect SW1_RUN_MODE setting: Ensure the SW1_RUN_MODE[1:0] bits are set to a valid operating mode such as PWM (0b01) or Auto-skip (0b11). If set to Off (0b00), the regulator will not operate.

- Watchdog or fault counter shutdown: If the watchdog event counter (WD_EVENT_CNT) or fault counter (FAULT_CNT) reaches its maximum, the PMIC may enter a fail-safe state, disabling regulators.

Recommended actions:

Confirm the EN1 pin is high and check the EN1_S status.
Read fault status bits and ensure fault protection is not disabling the regulator.
Verify SW1_RUN_MODE is not set to Off.
Check if INTB is asserted and inspect fault counters.
Measure the voltage at SW1LX to confirm regulator activity.

BRs, Tomas