TPS2514: Testing of TPS2514 Divider 1 DCP and Divider 2 DCP

You should acquire an EVM for the device. The EVM is configured with one port set to provide 5W and the other set to provide 10W. You can attach any USB device to the port and observe the D+/D- lines. You will see the part attempt to negotiate the possible apple divider negotiation on the scope. It will attempt to provide 2.7/2.0V or 2.0/2.7V on the D+/D- lines and if it does not detect an apple device, it will go through the BC1.2 negotiation, and will finally default to SDP power levels if no enhanced power connection can be achieved.

You can also look for a USB plug in tester that can emulate all of the charge modes that you wish to test. There are many of them available in the marketplace.

Please feel free to ask me any further questions you might have or click the customer thinks resolved button if I have fully answered your questions.

Regards,
Chuck

Dear Chuck,

Thanks for the quick response.

While testing TPS2514 devices with different Apple devices (with below 10% battery), we are not able to get 2.7/2.0V or 2.0/2.7V on the D+/D- lines, rather it is going to the BC1.2 negotiation, could you please help in this issues. We verified the design with the TPS2513EVM-527, but didn’t find any difference.

Regards,

TIJO

TPS2514 supports which all apple devices, I tried with iphone 6S (1A capability) and ipad pro 9.7 (2.1A capability) with below 10% battery..?
Still I am not getting 2.7/2.0V or 2.0/2.7V on the D+/D- lines. What will be the reason for this..? Or how to evaluate the device TPS2514, for apple 1A and 2.1A capability..?

Tijo,

If you do not see the Apple Phone/iPad providing the 2V on the D- line, then the TPS2514/TPS1513 will revert to DCP mode and attempt BC 1.2 negotiation. I have not personally tested the iphone 6S or ipad pro 9.7, but it is possible that they have elected to support BC1.2 higher in their priority because it allows for 1.5A of current in DCP mode which would charge an iphone 6S faster than Divider mode 1.

I am not certain why the ipad pro 9.7 would select a lower current option, but I will ask around my team to see if someone has more experience than me.

Dear Chuck,

Thanks for the reply..!

Is it possible to let us know how your technical team have evaluated this device TPS2514, for different Apple devices? Also, can you please share the list of Apple devices that your technical teams has verified the functionality (Divider 1 DCP and Divider 2 DCP) of TPS2514.

Tijo,

We cannot keep a list of devices compiled because we see that they change behavior regularly with firmware updates.

I am working to schedule a meeting with one of the designers from this device to see if there is anything I have missed. I am actually out of the office on Vacation today, but will follow up tomorrow.

Regards,
Chuck

Tijo,

The designer I need to speak to is out of the office today, so I will not be able to provide and update today.

Are you able to monitor the D+/D- and Vbus lines with no device connected and report the voltages that you see. This may provide me some insight into what is happening in your system.

Regards,
Chuck

Dear Chuck,

Below I tabulated the test result for TPS2514 devices with the no load condition and load condition (of different apple devices).

Parameter	No device connected	iphone 7	ipad pro 9.7	iphone 8
VBUS (V)	5.01	5.01	5.01	5.01
D- (V)	1.7	0.988	0.963	0.84
D+ (V)	2.17	0.989	0.967	0.838
Load current (A)		0.97	0.947	0.967

Regards,

TIJO

Tijo,

The no load results do not appear to be correct. The D+ line should charge to 2.7V and the D- line should charge to 2.0V upon power up with no load present. Are you seeing the same results on more than one device? I am slightly concerned that you are looking at a damaged device.

It appears that the Apple devices are connecting in the BC1.2 DCP shorted mode in all 3 cases. The TPS2514 supports this mode, so the downstream device seems to selecting this option.

I cannot easily explain the no device connection result.

Dear Chuck,

I am attaching the waveform for D+ (2.26V) and D- (1.78V). Afterwards its switching to 0.768V and 0.767V in the D+ and D- line with no load condition This same waveform we observed in our two boards, later we replaced with new chip (TPS2514) in one of the board also, and still we get the same waveform as below.

Below picture is for D+ line.

Below picture is for D- line

Regards,

TIJO

Tijo,

Are you able to provide me the schematic of your system. This is a public forum, but you can request to add me as a friend and private message me with the schematic.

I want to see if there is anything that might be loading the D+/D- lines because the output of the TPS2514 is a resistive divider that will be impacted by any loads on the lines.

Regards,
Chuck