Barrel Jack Detect
and PFET Enable
100 kΩ
10 kΩ
1.81 V
20 V
DC Barrel Jack
79
SLVSDC2B – FEBRUARY 2016 – REVISED AUGUST 2016
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Copyright © 2016, Texas Instruments Incorporated
10.2.2.2.1
Port Power Switch (PP_5V0 and PP_CABLE) Capacitors
The PP_5V0 supply is un-used in this application because 5 Volts is the default output voltage of the variable
buck regulator and is sourced to VBUS from PP_HV. PP_CABLE is still used and can supply up to 500 mA to
provide power to e-marked or active Type-C cables for SuperSpeed data signal conditioning. The PP_CABLE
supply, when PP_5V0 is un-used, is connected to a 4.7-µF ceramic (X7R/X5R) capacitor coupled with a 0.1-µF
high-frequency capacitor that must be placed close to the TPS65981.
10.2.2.2.2
HD3SS460 Control and DisplayPort Configuration
The Type-C port in this design supports DisplayPort and/or USB3.1 SuperSpeed data by adding the HD3SS460
multiplexer with GPIO input signals controlled by the TPS65981.
shows the DisplayPort configurations
supported in the system.
shows the summary of the TPS65981 GPIO signals control for the
HD3SS460. The HD3SS460 is also capable of multiplexing the required signals to the SBU_1/2 pins at the Type-
C port.
Table 13. Supported DisplayPort Configurations
DisplayPort Role
Display Port
Pin Assignment
DisplayPort Lanes
Configuration 1
UFP_D
Pin Assignment C
4-Lane
Configuration 2
UFP_D
Pin Assignment D
2-Lane and USB 3.1 data
(1)
Specific GPIO pins are used for simplicity, but the configurable firmware settings allow the HD3SS460 GPIO Events to be mapped to
any GPIO pin of the TPS65981.
Table 14. TPS65981 and HD3SS460 GPIO Control
(1)
TPS65981 GPIO
HD3SS460 Control Pin
Description
GPIO0
AMSEL
Alternate Mode Selection (4-Lane DP/2-Lane DP + USB3.1)
GPIO3
EN
Super Speed Multiplexer Enable
DEBUG1
POL
Type-C Cable Orientation
10.2.2.2.3
AC-DC Power Supply (Barrel Jack) Detection Circuitry
The system is design to either operate bus-powered over Type-C/PD or line-powered from the DC barrel jack.
The TPS65981 detects that the DC barrel jack is connected to GPIOn. In the simplest form, a voltage divider
could be set to the GPIO I/O level when the DC Barrel jack voltage is present, as shown in
. A
comparator circuit is recommend and used in this design for design robustness, as shown in
shows the barrel jack detection circuitry used in the dock or monitor application connected to GPIO2 configured
as an input.
Figure 77. DC Barrel Jack Voltage Divider