I am using the nPM1300 MIKROE Click board with an ESP32 over TWI (I2C).
I am facing an issue when VDDIO is sourced from VOUT2 using the onboard VDDIO_SEL jumper.
Although VOUT2 and VDDIO both measure 3.3 V, the PMIC Click board does not fully power up, VBUS is not detected, and I2C register read/write fails.
When I supply external 3.3 V from ESP32, everything works as expected.
Hardware Setup
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PMIC: nPM1300 (MIKROE Click Board)
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MCU: ESP32
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Interface: TWI / I2C
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Battery connected to VBAT
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NTC connected using 10 kΩ resistor
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Observed Behavior
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VOUT2 = 3.3 V
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VDDIO = 3.3 V
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Board does not power up
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Power LEDs do not turn ON
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VBUS not detected
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I2C registers cannot be read/write
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Working Case
If I supply external 3.3 V + GND from ESP32 to the Click board:
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Board powers ON
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LEDs turn ON
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VBUS detected
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I2C registers read/write correctly
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Question
Is VDDIO from VOUT2 a supported startup configuration, or is external VDDIO required for initial PMIC bring-up?
Could this be a power-up dependency issue where VOUT2 needs I2C configuration but I2C needs VDDIO?
