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USB EZ-PD Type-C

CypressUser
New Contributor

Hello Everyone,

My Lenovo yoga C930 and the charger stopped working after my dog bit the usb type c cable. After buying a new charger I found out that my laptop doesn't charge anymore. I opened the laptop and plug it in then I found the problem. The CYPD4226-40LQXI was heating up like crazy. I disordered the part and found that pin 23 V5V_P1 was shorted to GND.

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I ordered the part from Mouser and I should receive it tomorrow but after going through the datasheet again it seems this chip is programmable. Does it comme with a working firmware out of the box ? 

Thank you,

 

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6 Replies
ShifangZ_26
Moderator
Moderator

Hi ,

The CYPD4226 device will only pre-programmed with I2C bootloader from manufactuary. And then, it is supporting I2C bootloading. You can use EC on the board to programming the firmware directly. 

 

Best Regards,

Lisa

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CypressUser
New Contributor

Hi Lisa,

So this chip is blank and doesn't work properly without flashing the firmware first. Where can I find the firmware for this chip ? 

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OlEr_1999891
Contributor

Hi! Didn't notice that this "project" had another thread as well. Wrote some input here: https://community.cypress.com/t5/USB-EZ-PD-Type-C/Need-firmware-for-CYPD4226-Lenovo-Yoga-930/td-p/27... 

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CypressUser
New Contributor

Thank you for your input

I installed the new chip on the motherboard but the laptop still doesn't boot or charge. I have  3.3V on VDD and 5V on Vbus so I think there is a communication between the charger and the chip on CC. When I took some mesures without the chip soldered in there was 0V on Vbus.

The problem now the chip is not giving any reaction on pin 38 VBUS_C_CTRL_P1. 

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Do you think with the default FW we can have an output on this pin ? 

Thank you, 

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OlEr_1999891
Contributor

Hi! As far as I know there is no default FW loaded on a new CYPD4226, have you loaded default FW it via the SWD-pins?

Using PIN 38/39 for P and C MOSFET control is the default pins, so that is good. But did you actually get the schematic for the Lenovo laptop? Your screenshot looks like a Cypress reference design? 

Assuming your laptop doesn't start because the battery is empty (and not the laptop is more broken) and the only way to boot is first to charge it, the process for a "dead-battery" start is:

- Charger detects a downstream device based on CC lines is pulled down and enables 5V/0.5A on VBUS (looks OK)

- Laptop uses this 5V to at least start up the CYPD4226 and maybe DC/DC IC (the 3.3 VDD indicates this)

- USB-C PD signalling starts and laptop requests 5V / 3A first and opens up VBUS_SINK MOSFET (VBUS_C_CTRL_P1) and at some point upgrades VBUS to 20V.

There is another setup for dead-battery start up and that is that the VBUS_SINK mosfets are open when there is no voltage on VBUS_C_CTRL_P1 so VBUS 5V goes through when everything else is off. Measure VBUS_SINK before and after the MOSFETs. If after and VBUS_C_CTRL_P1 is 0 then it is correct behaviour I would say. When laptop switches to provide VBUS_SOURCE instead when you instead connect a device on that USB-C port, the VBUS_C_CTRL should go high and close the FET.

So the fact that you get 5V VBUS in is not a proof that the CYPD4226 is alive. The best way to know if your CYPD4226 is alive is to monitor the CC-pins and see if there is negotiation. If you have a PD-analyzer it is easy. Harder if not, the charger will try to establish communication and generate signals, but could be hard to see on a scope if the signal originates from the charger or the laptop. 

My next step would be to solder a cable on SWD_IO, SWD_CLK, GND and XRES, attach the PSoC programmer and then connect the charger to start the chip and see if it possible to program it.

$10:

OlEr_1999891_1-1617862566961.png

 

 

 

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CypressUser
New Contributor

Hi, From what I understood upon reading the schematics ( I am not an expert, only a student ) that I have shared here with the board view :
https://www.badcaps.net/forum/showthread.php?t=94059&highlight=c930

The number one scenario is more likely what should happen on this board. I am not sure if I have other problems on the logic board. Yesterday, I charged the laptop battery with an external charger.

 

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I tried to turn on the laptop with a full charged battery but unfortunately, the laptop didn't boot. I think I should now figure out first why the computer is not turning on with a full battery first. Then I should start debugging the cypd4226.


Thank you for your help 

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