Datasheet

IN
OC1
OC2
2
8
3
5
4
7
0.1 µF 10 µF
Internal
Function
OUT1
Power Supply
3.3 V
EN1
6
0.1 µF 10 µF
OUT2
Internal
Function
0.1 µF
10 µF
USB
Control
GND
V
BUS
D−
D+
EN2
GND
1
TPS2042B
TPS2041B, TPS2042B
TPS2043B, TPS2044B, TPS2051B
TPS2052B, TPS2053B, TPS2054B
SLVS514L –JUNE 2010–REVISED JUNE 2011 www.ti.com
Figure 35. High-Power Bus-Powered Function (Example, TPS2042B)
USB POWER-DISTRIBUTION REQUIREMENTS
USB can be implemented in several ways, and, regardless of the type of USB device being developed, several
power-distribution features must be implemented.
• Hosts/self-powered hubs must:
– Current-limit downstream ports
– Report overcurrent conditions on USB V
BUS
• Bus-powered hubs must:
– Enable/disable power to downstream ports
– Power up at <100 mA
– Limit inrush current (<44 Ω and 10 μF)
• Functions must:
– Limit inrush currents
– Power up at <100 mA
The feature set of the TPS204xB/TPS205xB allows them to meet each of these requirements. The integrated
current-limiting and overcurrent reporting is required by hosts and self-powered hubs. The logic-level enable and
controlled rise times meet the need of both input and output ports on bus-powered hubs, as well as the input
ports for bus-powered functions (see Figure 36 through Figure 39).
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