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TPS65988EVM: TPS65988 EVM

Jones rajasekar Arputham
Intellectual 365 points

Part Number: TPS65988EVM

Hi,

I bought the TPS65988 EVM and when am connecting the power adapter, I could not see the P*_VR_DC_DC outputs.

1. I have connected the external supply to the TP6, TP7 and still short P*_PP_HV & PP_HV* at J11... I didn't get the VBUS (Connected a phone at USB-C connector)

2. I have flashed the TPS65988 recovery image through FTDI and still facing the issues.

Please help me to fix this issue...I want to have VBUS outputs?

Thanks & Regards

Jones

  • 0
    TI__Mastermind 36756 points

    Hi Jones,

    Can you confirm that you are connecting a 20V power supply to the TPS65988EVM? You should be able to measure 20V at TP5 and 5V at TP6 and TP7. 

    Thank you,

    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    That works now and how can I change the DC outputs by toggling PDO0 and PDO1. I am seeing flashing failure.

    Thanks and Regards

    Jones

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    If you are seeing the VBUS LED's flashing, that typically indicates that there is an error on the Type-C Port. I would suggest connecting a known good device to ensure you can make a connection correctly.

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    1. I need J11 pinout for the TPS65988 EVM as in the PCB board

    2. How to change the VAR DC-DC output to different voltages? Is it through GPIO SW control or through automatic phone negotiation?

    3. One of my EVM board failing for  SPI flashing ? is it a way to fix it ?

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    1. The schematic for the TPS65988EVM is included in the TPS65988EVM User's Guide.

    2. The VAR DC-DC output will be automatically adjusted by the PD controller based on the PD contract that is negotiated.

    3. To ensure that the boards can be flashed, please ensure the barrel jack is connected

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    Thanks for the response and it works. Below please find Queries for evaluating the EVM boards as an SRC alone or SNK alone?

    1. TPS65988 as SINK only: We want to evaluate that, configuring the TPS65988 always as sink and drawing the maximum power from the power bank. 

    With the EVM, I have connected the VBUS PORT to the power bank through USB-C connector capable of supplying 15V/1.2A max and here we have disconnected the Power jack.

    I have changed the voltage divider resistor value for ADCIN1  to get 0.45v in order to force the Chip to configure for UFP – SINK 0-20V @ 0.9-3A (configuration 3)….Also tried bypassing the SPI flash by pressing Switch 6 while booting. But am not seeing the VBUS voltage at PP_HV pins. Tried flashing I2C patch and no luck.  Please clarify how to check with EVM board for sink configuration alone connecting it to Power bank at its VBUS port. Below is the configuration from an application note we want to evaluate

    2. TPS65988 as SOURCE only: We want to evaluate that, configuring the TPS65988 always as source and supplying power to phone at VBUS1 through negotiation, supplying a device without negotiation at VBUS2

    How can we limit the power for the phone (VBUS1) during negotiation, so that the device will always get power at VBUS2. We have checked the configuration tool to change this but the EVM DC-DC outputs are controlled by GPIO’s and we cannot override to check our configuration. is there a way to program the VBUS power?

    Another doubt is, what if we don't feed power to the TPS65988 and its CC lines staus. Is it pulled down?

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    1. Can you confirm that the shunts are placed on jumper J11? These are required to pass power to the rest of the EVM in dead battery mode. It is also required to hold down Switch S6 to boot into a default configuration. Otherwise, the TPS65988 will try to load from the SPI Flash. Switch S6 will need to be pressed before power is connected and released after power has been connected in order to boot into a default config.

    2. You can change the configuration on the EVM by using the TPS6598x Application Customization Tool. You can load a DFP only configuration and ensure that only 5V is present in the Source Capabilities register.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    For TPS65988 to be sink alone, I want to feed power bank input to VBUS and enable the internal power path which is VBUS to PP HV... I would like to see the PD chip do this rather doing a Shunt because shunt are for Selecting VAR and Power Jack ext path .

    Basically I wanna feed power to VBUS and see the the same power at PP HV

    Regards

    Jones

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    The Shunt needs to be placed in order for the power to go from PPHV to the rest of the system. Without the shunt, the rest of the board would not be powered.

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

     Hi Eric,

    Based on EVM if I need to configure TPS65988 as SINK, then the only way is to use the EXTERNAL PATH using PP_EXT and enabling external FET circuits.

    TPS65988 won't work like VBUS - PP HV without the PP_EXT and external circuits? Is that correct?

    My application is like POWER BANK connected to VBUS of PD CHIP1 in order to negotiate the maximum power.

    This PD CHIP1 PP_HV connected to PD CHIP 2 PP_HV Pins.

    PD CHIP2 VBUS1 connecting to phone and VBUS2 connected to the device as shown below. With the EVM i am verifying my application can work.

    Please confirm the TPS65988 as a sink for VBUS to PP HV, I always need PP_EXT and EXT FET CIRCUITS

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    You can use the internal power paths of TPS65988 to sink power as well. Additionally, I would recommend looking at the TPS65987D if you only have one type-C port per PD controller. Another comment: you would need the "PP HV" labeled net in your diagram to have a DC/DC converter on it before it goes to TPS65988 Chip 02 as the VBUS voltage would have to be reregulated to the 5V before connecting to something else.

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric, Thanks

    1. I want to verify this Vbus to PP HV internal path with EVM. I dont want to use external fet path and have to use internal path alone. Is that possible with EVM ?

    2. On your feedback,  using regulator for feed PD chip2 from  PD chip 1 : I want to get maximum power from power bank through internal sink path output PD CHIP 1 PP HV .. then I will source the phone after negotiation by PD chip 2 vbus which can goes upto PD CHIP 1 output. Is that possible?

    Or is that PD chips can source only at 5V 3A max ?

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    1. Yes, you can test this on the EVM. I would suggest using the TPS6598x application customization tool and editing the project to use either PPHV1 or PPHV2 as a sink path. By default, they are set up to be source paths. You can then directly program your configuration onto the EVM using the GUI tool. I would suggest removing the jumpers on J11 for this test to avoid back-feeding the DC/DC supplies that are connected to them by default. 

    2. If the PD adapter on PD Chip 1 PPHV is outputting 20V, there will be no way for PD Chip 2 to have 5V for sourcing without re-regulating the supply. However, if PD Chip 1 will only ever sink 5V, then this can work.

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    1. Thanks.. The TPS65988 internal path as sink works .. vbus to pphv path verified and I can see the power bank maximum power is linked by the PD CHip

    2. For TPS65988 as source, based on your replies it seems the the phone will negotiate with PD chip connected to its vbus and the chip itself control the regulators to provide the output

    A) so do we need regulators at PP HV to provide the negotiated voltage 5v, 9v, 12, 20v ?

    B) I cant give a fixed input ( exa 60w) at PPHV and the PD chip cant deliver the negotiated voltage connected to it vbus ?  PD chip always need regulators at PP HV input when we configures as source . Is that correct ?

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    2. 

    A. The PD controller will control the external DC/DC using GPIOs. For example, the TPS65988EVM uses the LM3489 as the DC/DC supply. The TPS65988 uses two GPIOs to control the DC/DC and change the output voltage. You will need something similar on your design to reregulate the voltage.

    B. No, the PD controller does not have a voltage regulator integrated, this would need to be implemented externally like on the TPS65988EVM

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Hi Eric,

    Thanks for the confirmation and I would like to integrate the Regulator circuits into my schematics

    1. Please provide me the Bill of materials for the Regulators page of EVM alone (Jones.rajasekar@light.co)

    2. For the source configuration,

       a) I am gonna use the same EVM regulator circuits at PP_HV1 and a smartphone connecting to VBUS1. Here I will connect the CC pins alone and not the USB-DP/DN. Is that ok for doing power swap?

       b) I am gonna use the same buck regulator U7 at PP_HV2 and my board power is hooked up to VBUS2...For this port no negotiation, no GPIO control and always this port is configured for 15W by connecting the CC2 pins with 5.1k pulled down to gnd and its DP2/Dn2 is shorted together.

      c) With the above configuration, shall I use the same TPS6598X configuration tool to flash the IC and set vbus port1 to my desired power to negotiate and left the port 2 as it is since its CC pins pulled down with 5.1k resistors?

     

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    1. The BOM for the TPS65988EVM is available in the TPS65988EVM User's Guide. We do not have a separate BOM for the DC/DC portion only.

    2.

    a. Yes, you can do a power role swap without D+/D-. The D+/D- lines are only needed to support BC1.2 charging or USB2.0 data.

    c. Yes, you will still need to use the TPS6598x application customization tool to configure the device for your application.

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Great, Thanks for your support Eric.

    one more Question, i want to use the EVM for TPS65988 as SRC on both the ports. Also, I want to source the EVM board through an external supply of 12v or 15V . Why the EVM is not working for less than 20v ?

    Can I override through application customization tool?

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    The EVM can source 5V, 9V, 15V, or 20V. By default, it will always negotiate the highest one available (20V). You can modify the configuration to remove the 20V Source Capability if you would like to test with 15V. 

    Thank you,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Thanks, Eric... Am started updating my schematics which includes 2xTPS65988 and the regulator circuits as in EVM.

    Once done i will send it for your review and we can close the thread after your comments.

    Thanks again for the great support

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    Thank you. One other thing to keep in mind is that the source capabilities of the PD Source port will need to be updated based on the PD contract made with the Power Bank. For example, if the Power Bank is only offering 5V @ 3A, you will not be able to source 20V on the other type-C port. You will also need to subtract the power consumed by the system. I would strongly recommend adding a microcontroller to your design to manage the power offerings of the source port based on what is available on the sink port.

    Thanks,
    Eric

  • 0 in reply to Eric Beljaars
    Intellectual 365 points

    Thanks, Eric,

    1. I am using the Power bank which can output 20V and verified with the EVM. I will verify the power bank source before using it for my application.

    2. I am using a SPI flash memory with TPS65988. If i want to use I2C connected to some host processor, shall I flash the PD chip through I2C when SPI flash is also present in the system after booting? But during the boot, the PD chip will always take the image file from Flash memory only... 

  • 0 in reply to Jones rajasekar Arputham
    TI__Mastermind 36756 points

    Hi Jones,

    If you have a host controller connected to the TPS65988 over I2C, you can still use the SPI Flash to boot the device and then adjust register settings based on the information you read from the PD controller over I2C.

    Thank you,
    Eric