C_CCn
R_RPD
RD_DB
RPD_Gn
RD_CC
RD_DB_EN
RD_CC_EN
34
SLVSDC2B – FEBRUARY 2016 – REVISED AUGUST 2016
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This resistance must be pin-strapped externally to configure the C_CCn pin to behave in one of two ways:
present an Rd pull-down resistance or present a Hi-Z when the TPS65981 is unpowered. During normal
operation, RD will be RD_CC; however, while dead-battery or no-battery conditions exist, the resistance is un-
trimmed and will be RD_DB. When RD_DB is presented during dead-battery or no-battery, application code will
switch to RD_CC.
Figure 19. C_CCn and RPD_Gn pins
When C_CC1 is shorted to RPD_G1 and C_CC2 is shorted to RPD_G2 in an application of the TPS65981,
booting from dead-battery or no-battery conditions will be supported. In this case, the gate driver for the pull-
down FET is Hi-Z at the output. When an external connection pulls up on C_CCn (the case when connected to a
DFP advertising with a pull-up resistance Rp or pull-up current), the connection through R_RPD will pull up on
the FET gate turning on the pull-down through RD_DB. In this condition, the C_CCn pin will act as a clamp
VTH_DB in series with the resistance RD_DB.
When RPD_G1 and RPD_G2 are shorted to GND in an application and not electrically connected to C_C1 and
C_CC2, booting from dead-battery or no-battery conditions is not possible. In this case, the TPS65981 will
present a Hi-Z on the C_CC1 and C_CC2 pins and a USB Type-C source will never provide a voltage on VBUS.
9.3.3 Port Power Switches
shows the TPS65981 port power path including all internal and external paths. The port power path
provides to VBUS from PP_5V0, provides power to or from VBUS from or to PP_HV, provides power to or from
an external port power node (shown and refered to as PP_EXT) from or to VBUS, and provides power from
PP_CABLE to C_CC1 or C_CC2. The PP_CABLE to C_CCn switches shown in
are the same as in
, but are now shown without the analog USB Type-C cable plug and orientation detection circuitry.