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TPS2511 and 1.2V/1.2V Mode

Hrag Kasparian
Prodigy 100 points
Other Parts Discussed in Thread: TPS2511, TPS2513, TPS2514

I have made a charger (power supply) that utilizes the TPS2511.  The power stage, which is a buck, is working perfectly.  I even tried running the buck up to 2.5A load with success (no current limit, etc.).  The TPS2511 is connected to the USB connector in the correct configuration to have Divider2 mode.  When I connect it to a Samsung Galaxy S3 and S4, I cannot have the DCP auto stay on the 1.2V/1.2V mode.  It always stays in the Divider2 mode (2.7V/2.0V).  I occasionally see the D+ and D- signals get the 1.2V on both, but then quickly returns and stays in Divider 2 Mode.  Charging these devices in Divider 2 mode is taking very long.  I measured the charged currents to be between 500mA and 800mA depending on if I have the screen on and other applications running, etc.

Is there something that I am overlooking?  Isn't the part supposed to automatically detect the signals from the device and finally lock into the correct charge mode/scheme?

  • 0
    Prodigy 100 points
    I have made a charger (power supply) that utilizes the TPS2511.  The power stage, which is a buck, is working perfectly.  I even tried running the buck up to 2.5A load with success (no current limit, etc.).  The TPS2511 is connected to the USB connector in the correct configuration to have Divider2 mode.  When I connect it to a Samsung Galaxy S3 and S4, I cannot have the DCP auto stay on the 1.2V/1.2V mode.  It always stays in the Divider2 mode (2.7V/2.0V).  Initially I see the D+ and D- signals get the 1.2V on both the D+ and D- pins, but then quickly return and stay in Divider 2 Mode.  Charging these devices in Divider 2 mode is taking very long.  I measured the charged currents to be between 500mA. I have an original Samsung 2.1A charger and I measured it's D+ and D- pins and read 1.2V on both and the phones charge very fast (>= 1.5A). Is there something that I am overlooking?  Isn't the part supposed to automatically detect the signals from the device and finally lock into the correct charge mode/scheme? Your feedback regarding this issue will be greatly appreciated. Thanks in advance.
  • 0 in reply to Hrag Kasparian
    TI__Mastermind 40395 points

    Hrag,

    This is currently being looked into. An answer will be posted when available.

  • 0 in reply to Darwin Fernandez
    TI__Intellectual 2795 points

    1. The charging current is sensitive with the INPUT voltage of portable device, and normally, the output voltage of  OEM charger is around 5.15V, in addition, TPS2511 has an 70mohm internal Rds,on. So in your test, can try to adjust the ouput voltage of USB port to see the charging current.

    2. As for the D+/D- 1.2V, can you hlep post a wave with 1s/100ms time scale.  

  • 0 in reply to Milo Zhu
    Prodigy 100 points

    8666.12Vin_D+_D-_PwrOn_WhileConn_to_GalaxyS3.tif

    4174.12Vin_D+_D-_PwrOn_WhileConn_to_GalaxyS3_Zoomed.tif

    As you can see from the waveforms, the TPS2511 is scrolling through the different D+/D- Modes, but does not stop and lock onto 1.2V/1.2V mode when I connect my Samsung Galaxy S3.

    Also, initially the voltage of the buck feeding the USB was 4.96V.  I adjusted the voltage to 5.18V, and the charge current very slightly increased, but it still did not lock into the 1.2V/1.2V mode.  Isn't it 1.2V/1.2V mode the correct mode for the Samsung Galaxy devices?  

    Thanks.

  • 0 in reply to Hrag Kasparian
    TI__Intellectual 2795 points

    The behavior looks normal, TPS2511 integrated 2.7V/2.0V mpde, 1.2V mode, and BC1.2 shorted mode, there would have some mode change. But now have some strange, why only 500mA charging current. We also test S3/S4, the charging current can be up to around 1A with 5V USB output.

    1. Did your test used the OEM charging cable?

    2. Did you try TPS2511EVM? Or maybe you also try TPS2513 EVM.

  • 0 in reply to Milo Zhu
    Prodigy 200 points
    Hi Milo,

    I have met the similar issue. I use TPS2514 for test. However, it looks the TPS2514 has never t lock into the 1.2V/1.2V mode. And the charging current is always 500mA. What are the requirements for the TPS2514 to lock into the 1.2V/1.2V mode. Thanks in a advance.