USB EZ-PD™ Type-C Forum Discussions

[Augustine_Yeh]

Hi Infineon

We try to test overcurrent on type c CYPD4126product, We short the VBUS in the device before connecting, We found that when we connect USB short device, The CYPD4126 try to output VBUS (turn on and off about every 250ms), Is that actions meet IF regulations? Can you explain and offer IF reference document for it, Thanks!!

[Wang_Fred]

Hello,

Can you let me know the power role of the CYPD4126 during the test as well as the test block diagram?

Thanks,

Fred

[Augustine_Yeh]

Hi Infineon

The power role is source only, We directly short the vbus to gnd on the device side before plugging in to motherboard, Thanks!!

[Wang_Fred]

Hello,

Your test scenario perhaps like SCP(short current test) instead of OCP. CCG4 has no capability to handle SCP. We can see that at the beginning VBUS_P_CTRL is at the low voltage to open the P MOS, so it looks abnormal.

Since the VBUS never goes high, the type-c machine should have not been entered. so it's on the earlier unknown stage, and it may not be able to meet the type-c spec.

I recommend you use a electronic load to sink a controllable current to test OCP instead of shorting the VBUS to GND before the normal start of type-c state machine.

Thanks,

Fred