TPS2547 Datasheet, PDF (26/42 Pages) Texas Instruments – USB Charging Port Controller and 3-Amp Power Switch With Load Detection

TPS2547
SLVSE11A – MAY 2017 – REVISED MAY 2017
www.ti.com
Feature Description (continued)
8.3.11 Thermal Sense
The TPS2547 protects itself with two independent thermal sensing circuits that monitor the operating temperature
of the power distribution switch and disables operation if the temperature exceeds recommended operating
conditions. The device operates in constant-current mode during an overcurrent condition, which increases the
voltage drop across power switch. The power dissipation in the package is proportional to the voltage drop
across the power switch, so the junction temperature rises during an overcurrent condition. The first thermal
sensor turns off the power switch when the die temperature exceeds 135°C and the part is in current limit. The
second thermal sensor turns off the power switch when the die temperature exceeds 155°C regardless of
whether the power switch is in current limit. Hysteresis is built into both thermal sensors, and the switch turns on
after the device has cooled by approximately 20°C. The switch continues to cycle off and on until the fault is
removed. The open-drain false reporting output FAULT is asserted (active low) during an overtemperature
shutdown condition.
8.4 Device Functional Modes
Table 1 shows the differences between these ports.
PORT TYPE
SDP (USB 2.0)
SDP (USB 3.0)
CDP
DCP
Table 1. Operating Modes
SUPPORT USB
2.0 COMMUNICATION
Yes
Yes
Yes
No
MAXIMUM ALLOWABLE CURRENT
DRAW BY PORTABLE DEVICE (A)
0.5
0.9
1.5
1.5
8.4.1 DCP Auto Mode
As mentioned above the TPS2547 integrates an auto-detect state machine that supports all the above DCP
charging schemes. It starts in Divider1 scheme, however if a BC1.2 or YD/T 1591-2009 compliant device is
attached, the TPS2547 responds by discharging OUT, turning back on the power switch and operating in 1.2 V
mode briefly and then moving to BC1.2 DCP mode. It then stays in that mode until the device releases the data
line, in which case it goes back to Divider1 scheme. When a Divider1 compliant device is attached the TPS2547
stays in Divider1 state.
Also, the TPS2547 automatically switches between the Divider1 and Divider2 schemes based on charging
current drawn by the connected device. Initially the device sets the data lines to Divider1 scheme. If charging
current of > 750 mA is measured by the TPS2547 it switches to Divider2 scheme and test to see if the peripheral
device still charges at a high current. If it does then it stays in Divider2 scheme otherwise it reverts to Divider1
scheme.
To USB 2.0 Host
TPS2547
BC1.2 CDP
BC1.2 DCP/
1.2V Mode
Divider1/2
D-
From Charging
D+
Peripheral
Controlled by CTL pins
settings
Copyright © 2017, Texas Instruments Incorporated
Figure 37. DCP Auto Mode
26
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Copyright © 2017, Texas Instruments Incorporated