TPS25750D Power Only Battery Charger Application

dugan yoon

Other Parts Discussed in Thread: TPS25750, TPS65987D

The data sheet shows a power only battery charger application configuration where both internal switches can be used to initially supply 5V and then negotiate 20V source for battery charging. We are running into software difficulties getting this to work. Is this a valid configuration that is supported? Is a specific BQ battery charger required for this configuration?

over 1 year ago

0 Matthew Schafer over 1 year ago

TI__Expert 4795 points

Hi Dugan,

Thanks for reaching out! I will have one of our apps engineers reach out to you shortly on this one.

Thanks,

Matt

0 Chris Sterzik over 1 year ago in reply to Matthew Schafer

TI__Guru 63961 points

Hello,

dugan yoon said:
We are running into software difficulties getting this to work. Is this a valid configuration that is supported?

What you are showing is consistent with figure 10-2, https://www.ti.com/lit/ds/symlink/tps25750.pdf#page=50

dugan yoon said:
Is a specific BQ battery charger required for this configuration?

I do not believe a specific battery charger is required, however, the I2C events need to be coordinated with the device. The GUI provides battery charger questions based upon the BQ device selected. These values are sent to the BQ device from the PD via I2C.

Regards,

Chris

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

Thanks for your reply Chris.

Is it possible to do a source only configuration where 5V or 20V can be sourced using the internal switches? The 20V bus shown on my schematic is actually the output of a buck switcher.

Best,
--Dugan

0 Chris Sterzik over 1 year ago in reply to dugan yoon

TI__Guru 63961 points

Hello Dugan,

No, I do not believe this is possible.

https://www.ti.com/lit/ds/symlink/tps25750.pdf#page=32

9.3.3 Power Paths The TPS25750 has internal sourcing power paths: PP_5V and PP_CABLE. TPS25750D has a integrated bidirectional high voltage load switch for sinking power path: PPHV. TPS25750S has a high volatge gate driver for sink path control: PP_EXT. Each power path is described in detail in this section.

9.3.3.1 Internal Sourcing Power Paths Figure 9-12 shows the TPS25750 internal sourcing power paths available in both TPS25750D and TPS25750S. The TPS25750 features two internal 5-V sourcing power paths. The path from PP5V to VBUS is called PP_5V. The path from PP5V to CCx is called PP_CABLE. Each path contains two back-to-back common drain N-FETs, with current clamping protection, overvoltage protection, UVLO protection, and temperature sensing circuitry. PP_5V can conduct up to 3 A continuously, while PP_CABLE can conduct up to 315 mA continuously. When disabled, the blocking FET protects the PP5V rail from high-voltage that can appear on VBUS.

Regards,

Chris

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

H I Chris,

Since the TPS25750 can't do what I want I checked into the TPS65987D. It has two internal bidirectional switches that can each do up to 5A. Can I use PPHV1 to initially source 5V and then switch to PPHV2 to source 20V? I would prefer not to have to use a variable supply.

Best,
--Dugan

0 dugan yoon over 1 year ago in reply to dugan yoon

Prodigy 130 points

The data sheet top of sheet 26 says "It is recommended to use PPHV1 as a sink path and PPHV2 as a source path." so it is unclear what is possible and what is not possible with this part.

0 dugan yoon over 1 year ago in reply to dugan yoon

Prodigy 130 points

0 Chris Sterzik over 1 year ago in reply to dugan yoon

TI__Guru 63961 points

Hello,

dugan yoon said:
Since the TPS25750 can't do what I want I checked into the TPS65987D. It has two internal bidirectional switches that can each do up to 5A. Can I use PPHV1 to initially source 5V and then switch to PPHV2 to source 20V? I would prefer not to have to use a variable supply.

Yes. I believe this is possible. Do you have the https://www.ti.com/tool/TPS65987EVM , to test out your configuration?

Regards,

Chris

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

I have a TPS65987EVM but need help configuring it. I can apply an external 5V supply on PP_HV1 and leave VAR_DCDC on PP_HV2. Can you help with guidance on how to configure DFP with 5V on PP_HV1 and 20V on PP_HV2?

0 dugan yoon over 1 year ago in reply to dugan yoon

Prodigy 130 points

Or maybe bettter, connect VAR_DCDC to PP_HV1 and SYS_PWR to PP_HV2, then configure VAR_DCDC to be 5V?

0 Chris Sterzik over 1 year ago in reply to dugan yoon

TI__Guru 63961 points

Hello,

Are you asking for help with the GUI?

Regards,

Chris

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

No, I was asking for help on the actual configuration settings to configure a 5V or 20V DFP source only application that uses fixed supplies.

0 Chris Sterzik over 1 year ago in reply to dugan yoon

TI__Guru 63961 points

Hello,

with the EVM connect PP_HV2 to VAR_DCDC and PP_HV1 to SYS_PWR.

In the gui configuration I set PP2 to 5V and PP1 to 20V and then in the GPIO control I updated the DCDC to provide 5V based upon PDO1 being negotiated.

test_project.pjt

Hope that is clear.

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

Hi Chris,

I downloaded your test_project.pjt file and loaded it then tried to export settings to device RAM but kept getting an Exception Encountered during import from Device.***ERROR in FTDI call (I2C DeviceWrite), status: 2 <type 'exceptions.Exception'>

Traceback (most recent call last):
File "dialogWindow.pyc", line 9772, in import_config
File "device_rw.pyc", line 707, in read_reg
File "hw_interface.pyc", line 417, in hw_i2c_write_no_stop
File "ftdi.pyc", line 615, in ftdi_i2c_write
Exception

I tested the EVM but because I couldn't export to device the PD behavior was unchanged from default.

I tried to create a new project for a DFP with 2 Bank 0 Source PDOs and was successful. I was able to export settings to device RAM with this project. Testing revealed 5V provided on attach, but no change when 9V requested, 15V requested, nor 20V requested. I am attaching this project for you to review. Do you know why I couldn't export your project?

DFP_project.pjt

Best,
--Dugan

0 Raymond Lin over 1 year ago in reply to dugan yoon

TI__Mastermind 34446 points

Hi Dugan,

Chris is out of office and will return by 10/10/2023. Thank you for your patience!

Thanks and Regards,

Raymond Lin

0 Chris Sterzik over 1 year ago in reply to dugan yoon

TI__Guru 63961 points

Hello,

Please match the GPIO functions. You still have GPIO20 for PDO3 which does not exist.

I do not know why the export to ram is not working. Have you tried to 'Flash from current project" under binary? That is what I used when testing with the EVM.

Chris

0 Chris Sterzik over 1 year ago in reply to Chris Sterzik

TI__Guru 63961 points

Hello,

dugan yoon said:
Do you know why I couldn't export your project?

Do you know if the device is in APP mode or boot mode?

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/978786/tps65987d-tps65987evm-ftdi-firmware/3624363#3624363

Regards,
Chris

0 dugan yoon over 1 year ago in reply to Chris Sterzik

Prodigy 130 points

The device is in APP mode when export to RAM doesn't work. Binary > Flash from current Project works. It looks like a DFP (no CC1 toggling with nothing attached) and it switched to 20V when asked but not 9V nor 15V. I will try to look into the GPIO functions further so my own project can work too.

Power management

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TPS25750D Power Only Battery Charger Application