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TPS65987DDJ: TPS65987DDJ - Does not toggle Sink PDO Negotiated

Holden Sandlar
Prodigy 10 points
Part Number: TPS65987DDJ
Other Parts Discussed in Thread: TPS65987, TPS65987D, , TPS65988

Hi,

We have been working on a custom board using the TPS65987 part. We originally designed for the DDH variant, but when that part was out of stock we installed the DDJ part.

In general, testing has been going OK. We wired up a dev kit to program the SPI EEPROM externally. We're using the part as a SINK-ONLY -- it is used to externally power the system and charge a battery (if installed). The part boots to APP mode, and indicates that it has negotiated a valid PD SINK contract. We've configured GPIO16 to control a redriver mux selection based on cable orientation and see this working as expected.

We then configured GPIO17 to trigger based on PDO0 SINK contract negotiated. We never see this IO toggle, even though the registers indicate the sink contract was negotiated successfully. If after the sink contract is negotiated, we turn on substantial power draw on our system things work fine. However, if we turn on power draw prior to the sink contract being negotiated, we get an overcurrent condition and the source device turns off it's port (causing VBUS and everything on the TPS65987 to toggle repeatedly). Ultimately, we are trying to use GPIO17 as a trigger to indicate that we can start drawing substantial power from the USB interface.

After smashing our heads into the wall for a while we have come across this E2E posting, which appears to indicate the same problem: https://e2e.ti.com/support/interface/f/interface-forum/871128/tps65987ddj-sink-pdo-negotiated-trigger-event-not-triggering-to-send-i2c-command-to-bq25703a

Based on the responses here, it is basically stated that the DDJ part cannot be used with the application customization software. Even though the part boots, it will not honor the configured settings of the software. Is this really the case???????? This seems absurd. The datasheet for the TPS65987D doesn't specify DDH or that the DDJ variant doesn't offer the same features. The application customization software clearly generates valid, bootable, firmware for the DDJ part. What do we have to do to be able to use the PDO0 SINK Negotiated event??? Is there different software that we have to use? If the answer is switch to a different part we will 100% be dropping TI from this and all future designs.

Any feedback would be appreciated.

Thanks

  • 0
    TI__Genius 9630 points

    Hello,

    This post is correct, you cannot use the TPS65987DDJ with the GUI tool. The DH variant is what you need. Please order the TPS65988 in place of the TPS65987DDJ, as the TPS65988 will work in place of the TPS65987DDH.

    Thanks,

    Emma