ZHCSIY2B July 2018 – August 2021 TPS65988
PRODUCTION DATA
When one of the TPS65988 ports is configured as a DFP, the device detects when a cable or a UFP is attached using the Cx_CC1 and Cx_CC2 pins. When in a disconnected state, the TPS65988 monitors the voltages on these pins to determine what, if anything, is connected. See USB Type-C Specification for more information.
Table 8-1 shows the Cable Detect States for a DFP.
| C_CC1 | C_CC2 | CONNECTION STATE | RESULTING ACTION |
|---|---|---|---|
| Open | Open | Nothing attached | Continue monitoring both C_CC pins for attach. Power is not applied to VBUS or VCONN until a UFP connect is detected. |
| Rd | Open | UFP attached | Monitor C_CC1 for detach. Power is applied to VBUS but not to VCONN (C_CC2). |
| Open | Rd | UFP attached | Monitor C_CC2 for detach. Power is applied to VBUS but not to VCONN (C_CC1). |
| Ra | Open | Powered Cable-No UFP attached | Monitor C_CC2 for a UFP attach and C_CC1 for cable detach. Power is not applied to VBUS or VCONN (C_CC1) until a UFP attach is detected. |
| Open | Ra | Powered Cable-No UFP attached | Monitor C_CC1 for a UFP attach and C_CC2 for cable detach. Power is not applied to VBUS or VCONN (C_CC1) until a UFP attach is detected. |
| Ra | Rd | Powered Cable-UFP Attached | Provide power on VBUS and VCONN (C_CC1) then monitor C_CC2 for a UFP detach. C_CC1 is not monitored for a detach. |
| Rd | Ra | Powered Cable-UFP attached | Provide power on VBUS and VCONN (C_CC2) then monitor C_CC1 for a UFP detach. C_CC2 is not monitored for a detach. |
| Rd | Rd | Debug Accessory Mode attached | Sense either C_CC pin for detach. |
| Ra | Ra | Audio Adapter Accessory Mode attached | Sense either C_CC pin for detach. |
When a TPS65988 port is configured as a DFP, a current IH_CC is driven out each C_CCn pin and each pin is monitored for different states. When a UFP is attached to the pin a pull-down resistance of Rd to GND exists. The current IH_CC is then forced across the resistance Rd generating a voltage at the C_CCn pin.
When configured as a DFP advertising Default USB current sourcing capability, the TPS65988 applies IH_CC_USB to each C_CCn pin. When a UFP with a pull-down resistance Rd is attached, the voltage on the C_CCn pin pulls below VH_CCD_USB. The TPS65988 can be configured to advertise default (500 mA or 900 mA), 1.5-A and 3-A sourcing capabilities when acting as a DFP.
When the C_CCn pin is connected to an active cable VCONN input, the pull-down resistance is different (Ra). In this case the voltage on the C_CCn pin will pull below VH_CCA_USB/1P5/3P0 and the system recognizes the active cable.
The VH_CCD_USB/1P5/3P0 thresholds are monitored to detect a disconnection from each of these cases respectively. When a connection has been recognized and the voltage on the C_CCn pin rises above the VH_CCD_USB/1P5/3P0 threshold, the system registers a disconnection.