How to drive buck-boost device with PWM from a CYPD3174 and be PD compliant?

[AlMa_1521636]

I have loaded the example pa_opto_fb firmware for the CYPD3174 CCG3PA device to use a a baseline to develop a PD controller for our power adapter project. I need to use a PWM to drive a buck-boost device to output the voltage that was negotiated in the PD contract. How do I add PWM functionality to the firmware to control the PWM input of the buck-boost and still be PD compliant for the certification process? There is a maximum time allowed between the host requesting a voltage and the host receiving the requested voltage. How do I set this up so that I meet the USBC Power Delivery requirements?

[ShifangZ_26 · Accepted solution]

Hi Allen,

If you have chance to open the example code of CYPD3171-24LQXQ_cla or CYPD3171-24LQXQ_pb, the PWM have been added in those two projects.

The PD compliant for the certification is not only because of which feedback selected -- whether you are opto feedback or direct feedback (=FB direct feedback, I2C/GPIO/PWM direct feedback), it is depends on the timing of CC and VBUS. So that it is possible to pass the PD compliant for the certification, but you need much more efforts than existing Cypress reference design. The firmware efforts will based on PD compliant for the certification test results.

Best Regards,

Lisa