Datasheet

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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
TPS2046B
USB POWER-DISTRIBUTION REQUIREMENTS
TPS2045B , TPS2055B
TPS2046B , TPS2047B
SLVS532C – JULY 2004 – REVISED OCTOBER 2007
Figure 25. High-Power Bus-Powered Function (Example, TPS2046B)
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 μ F)
• Functions must:
– Limit inrush currents
– Power up at <100 mA
The feature set of the TPS204xB/TPS2055B 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 26 through Figure 27 ).
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Product Folder Link(s): TPS2045B TPS2055B TPS2046B TPS2047B