[Schematic Review] CYPD3177 for both low voltage, low current and high voltage, high current

[pgrinalds]

Hello there,

I would like to request a schematic review please. My application has two use cases:

1. Programming: In this case I will be connecting to a computer for programming through USB-UART bridge. Hence why I have the minimum voltage set to 5V and the current set to 750mA.

2. Operating: The other case will be to provide 20V and request up to 3A from the USB PD host supply. Hence why I set it to VMax at 20V

Questions:

1. Because I set the current request to 0.75A to satisfy the programming needs, will it prevent the draw of more current when in the operating use case?

2. On a previous version of this, when I would plug into the wall PD supply, I would hear a component pop, but it would still supply 20V. Do the power FETs and diodes and other passive components look correct?

3. Additionally, do you see anything wrong with using the LM2576S-3.3 to regulate for control level voltage use off of the PD VBUS?

Thank you so much for your consideration!

Best,

Peter

[HmdRahmathulla · Accepted solution]

Hi @pgrinalds ,

Thank you for posting infineon community.

Yes, since you have limited you current as 750mA, you will get the maximum of 750mA from 5V to 20V.

as per your requirement you need 20V 3A for operating condition.  by this HW configuration it can't able to request for more current.

these are few findings in the schematic.

1. Remove R9, as per the design, to achieve 20V you have pull-up the VBUS_MAX without any Pull-Down.

2. To increase the Current limit to 3Amp, the pin ISnk_Coarse has to pull-up and pull-down with 5.1K. refer below image

Best Regards,

Mohamed Rahmathulla

[pgrinalds]

Hello Mohamed,

Thank you so much for the reply.

I will remove that resistor from my design to achieve the full 20V. Additionally, I will change the current draw during operation to 3Amps and make a jumper to request 750 mA during programming.

Thank you for the assistance.

Best,

Peter