Datasheet

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USB HYBRID HUB

TPS2070

TPS2071

SLVS287B – SEPTEMBER 2000 – REVISED SEPTEMBER 2007

A USB hybrid hub can be simply implemented using the TPS2071 USB power controller and a TUSB2046 USB

hub controller as shown in Figure 38 . The TPS2071 USB power controller provides all the power needs to the

four downstream ports and meets all the USB power specifications for both self-powered hubs and bus-powered

hubs. The integrated 3.3-V LDO of the power controller is used to provide power for the hub controller and any

other local functions (e.g., transient suppressor SN75240 ), which saves board space and cost. The TPS2071

also provides the hub controller with a power-good (PG) signal that connects to the RESET input of the hub

controller to reinitialize the hub automatically when switching between self-powered mode and bus-powered

mode whenever the self-power supply is connected or disconnected. The amount of time in which the hub

controller is kept in a reset state is controlled by a capacitor connected between the PG_DLY pin of the power

controller and ground.

By using an external N-channel MOSFET and the TPS2071 internal voltage-regulator controller, a regulated 5-V

self-powered source can be generated from an input voltage range of 6 V to 9 V (see Figure 38). In this

configuration, the internal voltage regulator controller is enabled by connecting the EN_REG input to the BP

input. Using the internal voltage regulator controller also requires connecting a 0.01- μ F capacitor between CP_P

and CP_M of the TPS2071 power controller. Also, a 0.1- μ F capacitor is needed between VCP of the power

controller and ground.

Product Folder Link(s): TPS2070 TPS2071