Hi,
I am currently debugging an MP5031GRE-00A3 implementation and would like to clarify a few aspects of the device operation.
Our setup uses a non-I2C DC/DC converter together with DPS1135 USB PD power switch, controlled through the MP5031 GPIO outputs. The MP5031 is powered and accessible via I2C, and Type-C attach detection appears to work correctly.
Current observations
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VCC is within the valid operating range.
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I can communicate with the MP5031 through I²C.
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ANALOG_DETECTED_TYPECchanges when a phone is connected. -
ATTACH functionality works when configured to GPIO5.
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PD negotiation does not appear to start.
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VDRV never becomes active.
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No VBUS voltage appears at the USB-C connector.
Questions
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Does the MP5031 require a valid voltage on the VBUS/VBUS_P pin before PD negotiation can proceed?
In the forum thread below, VBUS was mentioned as one of the first items to verify:
In our design, VBUS is generated by an external DC/DC converter which is enabled through a path ultimately controlled by MP5031. We are trying to understand whether the MP5031 expects VBUS to already be present before it will continue the PD state machine and send Source Capabilities.
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Is VDRV intended to drive the enable pin of an external power switch/DC/DC converter directly?
The datasheet specifies:
Gate driver voltage (VDRV - VBUS) = 4.85V
We currently connect VDRV directly to the EN pin of the external power switch path circuitry. Is this a supported use case, or is VDRV intended only for driving an external MOSFET gate?
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For a non-I2C DC/DC converter implementation, is the expected initialization sequence:
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Configure PDOs
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Configure GPIO functions
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Set
SLAVE_DEVICE_SEL = 101b -
Set
SEND_SRC_CAP = 1
Or are there additional required registers that must be configured before PD negotiation can start?
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Any guidance would be greatly appreciated.