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  • TI Thinks Resolved

TPS65987EVM: AC adapter does not output correctly

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Replies: 3

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Part Number: TPS65987EVM

Hello,

The following phenomenon is occurring. Is there a solution to get 20V output correctly?

(1) When the TPS65987EVM with the following settings written in Flash and the AC adapter are connected by Type-C USB cable and AC100V is input, the voltage shifts at 0V, 5V, 20V.
D16, D17, D19, D20 blink as the voltage shifts.

VBUS (TP1) -GND (TP5) is probed to monitor the voltage.

New Project⇒TPS65987DDH⇒Standard(Recommended)⇒DRP,prefers power source
Binary⇒Flash from current project

(2) After (1), change the setting to Sink only as shown below, and as a result of measuring the voltage again, only 5V is output.
Also, as shown in the attached image, SYS_PWR (D19) lights up immediately after AC input, but turns off in a few seconds. After that, 5V remains output.

New Project⇒TPS65987DDH⇒Standard(Recommended)⇒UFP only
Binary⇒Flash from current project

Regards,

Oryoji

  • Hi Oryoji,

    This EVM has no AC on it. You can either use the EVM to source by plugging in a barrel jack and plugging a sink into the Type-C connector. The barrel jack power of 20V is then either passed through or stepped down to 5, 9 ,or 15V. This is done through a DC/DC converter. If you want to use the EVM as a sink, unplug the barrel jack and connected the EVM to a USB Type-C source, that will output a steady 5, 9, 15, or 20V. One EVM that demonstrates this well is the Power Duo Source and Sink Board.

    If you haven't modified the EVM at all, you need to change the jumper locations as shown from the EVM User's Guide below:

    Please read the TPS65987EVM User's Guide. This will explain the features of the EVM in depth, and details the jumper locations and their functions.

    Regards,

    Emma 

  • In reply to Emma Hoying:

    Hello,

    This time, EVM is used as Sink.
    No barrel jack connection.
    Jumpers are connected to sink (1-2PIN) for both J4 and J5.
    Adding to (2), 5V is input to VBUS, but PP_HV1 drops to 0V immediately after 5V output. As a result, the output of SYS_PWR is also reduced. It is likely to occur when connecting the PC and EVM.

    What could be the reason why PP_HV1 of USB PD Power Path is turned off?

    Is it correct to recognize that if I use USB-C-PD-DUO-EVM as a Sink, use an AC adapter on the source side, connect a Tyep-C USB cable, and press the 20V button on the Sink side, 20V will be output correctly?

    Regards,

    Oryoji

  • In reply to user6403867:

    Hi Oryogi,

    You still need to change your jumpers. Unless you make hardware changes, J4 needs to be connected to pins 1 and 2 and J5 needs to be connected to pins 2 and 3. This is because these are dedicated source and sink paths in the EVM hardware. Please try this and update this issue.

    These devices and EVMs do  not take an AC input, only DC, provided through barrel jack. If you use the USB-C-PD-DUO-EVM sink board and connect it to the source board, and press the 20V button on both boards, then 20V will be output.

    Thanks,

    Emma

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