CYPD3174-24LQXQ output voltage change issues

[saan_3612016]

Dear all,

I am using the CYPD3174-24LQXQ in a high density AC/DC 65W power adapter as a PD controller with optocoupler feedback.. I attach the schematic.

The current shunt is 5mohm.

I am experiencing issues with the output voltage change only at light load conditions below 500mA load current.  In the attached scope picture I have the output voltage going from 5V to 20V which was requested. After that the PD load requests 5V output, the converter changes the output to 5V, all normal so far. After this the PD load is requesting a 12V voltage, the converter goes to 12V, stays at 12V for around 200ms , goes to zero(P channels turned off). This happens two more times, after this , I guess the PD controller needs to be reset to work again.

I am only experiencing this below 500mA load current. At 3A load this issue is not present. I have tried everything I could think of to solve this issue but could not find a solution?

Is this issue known to Cypress PD controller? Is there any fix for this?

Thank you in advance

Andrei Savu

R&D Electrical Engineer

Rompower Energy Systems

www.rompower.com

[ShifangZ_26]

Hi Andrei Savu,

Could you please kindly try to disable OCP/OVP/UVP/SCP (I assume you are not enabled OTP) in config.h file one by one and make sure if the hard reset is caused by any one of them? It seem the hard reset is caused by CCG3PA's protection.

Best Regards,

Lisa

[saan_3612016]

Dear Lisa,

I using the EZPD GUI, and I have disabled all protections but with no effect. Do I need to open the firmware files in Psoc Creator and do the changes there?

[ShifangZ_26 · Accepted solution]

Hi ,

You can to disable it in config.h to make sure all of them is disabled. If the issue is still here with all of protections was disabled on config.h, you need to check others, which is means the hard reset is not caused by any protection faults.

Best Regards,

Lisa