TPS25751: USB output OCP detection threshold and period during SRC operation

Hi Kono-san, 

Couple follow-up questions for clarification: 

Tomonori Kono said:

(1)How to set the output to 5V0.9A and output a peak of 1.6A (approximately 5ms)

Is this for a PD contract or just a Type-C (non-PD) connection? 

Tomonori Kono said:

(2)IC operation specifications
     -OCP detection threshold when set to 5V0.9A PDO
     -OCP detection period
     -PP5V_UVLO setting value when outputting SRC
     -Register setting related the above

Will look into this and get back to you with details. 

Thanks and Regards,

Raymond Lin

Hi Raymond-san

(1) requirement is just a Type-C(non-PD) ,but I also set PDO.
    In my setting, I get OCP waveform below (5V1.5A setting).

     -PDO 5V0.9A  : detected approx.1.2A
        setting /Reg29h=0x01100000
                     Reg32h=0x2601905A2AA801
     -PDO 5V1.5A  : detected approx.1.77A
        setting /Reg29h=0x01100001
                     Reg32h=0x260190962AA801
     ※Common:Reg28h=0x2F4902 　→OVP setting3 (114%)
　　　　　　　　　　　　　　　　→I_LIM5V is also set to 114% or setting X?

Hi Kono-san, 

Apologies for the delayed response, the OVP setting for PP5V does not also apply for ILIM_5V (PP5V OCP). The current limit for PP5V is automatically calculated by the PD internal firmware. The results you're seeing is normal margin/threshold as this is also used to account overshoot when the sink side is drawing current.

The time it takes for TPS25751 to respond to overcurrent is tiOS_PP_5V: 

The duration of the overcurrent event before disabling PP5V is tILIM:

PP5V ILIM thresholds are automatically selected by the firmware based on these thresholds: 

Thanks and Regards,

Raymond Lin

HI Raymond-san

>The current limit for PP5V is automatically calculated by the PD internal firmware.
>PP5V ILIM thresholds are automatically selected by the firmware based on these thresholds: 
Is the PP5V ILIM set as below?
 -PDO=5V0.9A  : setting0 1.15~1.36A
 -PDO=5V1.5A  : setting1 1.61~1.90A

>The duration of the overcurrent event before disabling PP5V is tILIM: 5.1ms
So if the VBUS current remains above the ILIM value for 5.1 ms, the PP5V output will stop?
If the VBUS current falls below the ILIM value, will it be reset at that point and the time will start counting again?

Will the OCP be detected in the waveform below when set to 5V0.9A?
　※Same waveform as the first post

Hi Raymond-san

　When is the following OCP set ?
　Please provide a specific PDO setting range.


>If the VBUS current exceed setting 0 (1.15A-1.36A) for over 5ms then OCP will not be detected. 
 [Will Be detected] is correct, right?

Thanks and Regards,

HI Raymond san,

>For 900mA, the OCP setting is set to setting 0 (1.15A to 1.36A).
Sorry, I understood that.
Having said that, I would like to know the OCP setting value when the PDO is set to more than 5V1.5A for future reference.
I think the OCP is determined only by the current value within the PDO.
Please tell me the upper limit of the PDO current for each OCP.
Please add or revise the list below.

　PDO UpperLimit：OCP
　　　　≦0.9A？：min1.15A　/setting0
　0.9A<,≦1.5A？：min1.61A　/setting1
　1.5A<,≦xxxA？：min2.3A
　xxxA<,≦xxxA？：min3.04A　/setting3
　xxxA<,≦xxxA？：min3.22A　/setting4

Thanks and Regards,

Hi Kono-san, 

Looking into the specific settings and will get back to you by tomorrow. 

Thanks and Regards,

Raymond Lin

Hi Raymond-san,

How about the specific settings I asked in Oct 22 ?

Thanks and Regards,

Hi Raymond-san

Thank you for reply.
I understood it.

Thanks and Regards,

Kono