Introduction
2
SLVUB94 – October 2017
Copyright © 2017, Texas Instruments Incorporated
TPS254900AQ1EVM-003 Evaluation Module
1
Introduction
The TPS254900AQ1EVM-003 allows reference circuit evaluation of TI's TPS254900A-Q1 automotive USB
charging port controller with integrated power switch, cable compensation, and short-to-battery protection.
The TPS254900AQ1EVM-003 provides the electrical signatures on DP_IN and DM_IN to support all
current charging schemes. The TPS254900A-Q1 incorporates USB cable voltage drop compensation by
linearly sensing the port current and automatically adjusting the output voltage of the LMR14030SDDAR to
keep the cable end device voltage within the normal operating range. The TPS254900A-Q1 incorporates
up to an 18-V short to battery protection for VBUS, DP_IN and DM_IN.
1.1
Features
The EVM supports the following features:
•
TPS254900A-Q1 built-in IEC 61000-4-2 ESD protection on DP_IN and DM_IN pins
•
Linear USB cable voltage droop compensation
•
The TPS254900A-Q1 is fully AEC Q100 qualified
•
Built-in short to battery protection and notification on VBUS, DP_IN and DM_IN
•
LMR14030SDDAR high-performance 2.2-MHz automotive-qualified DC/DC converter
1.2
Applications
The EVM can be used in the following applications:
•
Automotive infotainment system
•
Automotive USB charging box
2
Description
The TPS254900AQ1EVM-003 enables full evaluation of the TPS254900A-Q1 device. Refer to the
schematic in
. An automotive voltage range input is applied at the J1 connector. The input voltage
is regulated by the LMR14030SDDAR buck regulator (U1) and associated circuitry. This provides a
nominal 5-V, 3-A output at +5 V
DC
for the TPS254900A-Q1 (U2).
The TPS254900A-Q1 internal power switch co5 V
DC
furnished by the LMR14030SDDAR regulator
to VBUS at the downstream facing USB connector, J5. When the internal power switch is ON, the D6 LED
(green) illuminates. USB 2.0 data can be passed through the TPS254900AQ1EVM-003 from J5 to J4
when the TPS254900A-Q1 is configured for either SDP or CDP mode using the J6 header. The
TPS254900A-Q1 status and fault conditions can be detected using the D3 (blue) and D2 (red) LEDs,
respectively.
The TPS254900A-Q1 provides system-level ESD protection in accordance with IEC 61000-4-2 up to ±8-
kV contact and ±15-kV air discharge at the DP_IN and DM_IN signals going to J5. These pins as well as
VBUS pin will also provide detection of shorts to the battery by triggering the FAULT logic and illuminating
D2.
The TPS254900A-Q1 provides USB cable voltage droop compensation at the load through the use of the
CS pin. Sinking current into the CS pin mirrors the current through the TPS254900A-Q1 power switch at a
rate of 82 µA/A. The CS pin current is summed with the LMR14030SDDAR regulator feedback current
through R1 causing the voltage at +5 V
DC
to change with USB downstream load current. The +5 V
DC
increases linearly as load current increases. This compensation will keep the load end voltage close to 5
V
DC
. The default compensation resistor values (R1 and R4) target a USB cable resistance of 200 m
Ω
.
Refer to the TPS254900A-Q1 data sheet for more information.
The TPS254900A-Q1 provides a current detection function through the use of the IMON pin. Connect a
resistor between IMON and GND. The system can detect the load current in real time by monitoring the
IMON voltage.
