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USB EZ-PD Type-C

hata_3396041
New Contributor

Hello

Customers are using the CY4533 kit for evaluation.

V_MIN = VMAX = 5V, current is set at ISNK_COARSE = 2A, ISNK_FIN = 0A.

When the PD compatible adapter and the evaluation board were connected with a Type-C cable, the VBUS Power LED emitted light and the 5V voltage could be confirmed from the VBUS line.

Even when a PD-incompatible Type A adapter and evaluation kit are connected with an A to C cable, the VBUS Power LED emits light and is output from the VBUS line at a voltage of 5V.

(Maximum output of Type A adapter is 5V / 2.4A)

After checking the kit guide, it was recognized that the Fault pin was set up (red LED was lit) and 5V / 900mA was output from Safe_5V Output.

However, the output from Safe_5V Output could not be confirmed.
Why is this?

Best Regards

Hayato 

 

 

 

 

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1 Solution
MallikaK_22
Moderator
Moderator

Hello Hayato,

Apologies for miscommunication.

Please note that no Legacy charging protocols are supported by CYPD3177. Following this, DP/DM lines in BCR are not implemented. They are simply left unconnected.

Regards,

Mallika

 

 

 

Mallika

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5 Replies
MallikaK_22
Moderator
Moderator

Hello Hayato,

In BCR, there are 2 different outputs- DC_OUT and SAFE_5V_OUT. DC_OUT is the output of the BCR board (can be from 5V to 20V depending upon the power ability of the adapter) while SAFE_5V_OUT is the default 5V provided in case of a fault and when the 5V default load switch  is turned ON. 

The Fault LED is turned on in the following cases-

a) The Type-C power adapter cannot provide the voltages or current required by the system.

b) Voltage on VBUS is 20% below the VBUS_MIN setting or 20% above the VBUS_MAX setting.

When the Type-C power adapter cannot provide the voltage or current set in the selector pins, the BCR part negotiates for  5V at 900mA and turns ON the Safe 5V Load Switch (Q2 on the EVK).

Regards,

Mallika

Mallika
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hata_3396041
New Contributor

Hello Mallika-san

I expected the Fault pin to be enabled when connecting to an adapter that doesn't have a PDO configuration like this one.
In this case, does it mean that the Fault pin was not enabled because the BCR confirmed an output that exceeded the current value set by ISNK_COARSE = 2A, ISNK_FIN = 0A.?

 

If one side is a Type-A adapter, it is not possible to negotiate with the CC pin, so supply information is exchanged using D + and D- according to BC1.2, and as a result, 5V / 900mA is output. Is it ?

 

Best Regards

Hayato

 

 

 

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MallikaK_22
Moderator
Moderator

Hello Hayato-san,

For the legacy USB Type-C to Legacy cable assemblies which have Rp termination integrated, BCR will treat it as a non-PD source.

So the working will be as per the Type-C specification and not the PD specification, i.e. the PDOs set don't work in this situation. This means that the device wont be checking for FAULT condition based on configured PDOs and actual voltage from source.

Hence, the default 5V provided will not be recognized as a fault condition.

Regards,

Mallika

Mallika
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hata_3396041
New Contributor

Hello Mallika-san

Thank you. I understand the Type A adapter.
In the evaluation environment, 5V / 2A is output from the Type A adapter.

●In this case, if the D + and D- lines are disabled, will power not be supplied? (Is it dangerous?)

 

●Is it possible to cut off the power supply when the current of 2A or less can be passed in BCR regardless of the shape of the adapter?

I want to supply power only with an adapter that can pass a current of 2A or more.

 

Best Regards

Hayato

 

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MallikaK_22
Moderator
Moderator

Hello Hayato,

Apologies for miscommunication.

Please note that no Legacy charging protocols are supported by CYPD3177. Following this, DP/DM lines in BCR are not implemented. They are simply left unconnected.

Regards,

Mallika

 

 

 

Mallika

View solution in original post

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