Cypress CY4603, Руководство пользователя

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68 HX3 Kits User Guide, Doc. #: 001-91203 Rev. *D
Hardware
DVK contains two onboard DC-DC regulators to provide 3.3-V and 1.2-V power supplies to the HX3
hub controller. A 5-V input from the AC-DC adapter is directly passed to the downstream ports via
power switches.
The HX3 hub controller supports the I
2
C communication interface; it can support both slave and
master modes. On the DVK, an I
2
C EEPROM is interfaced to the hub controller to store the configu-
ration data and firmware, with the hub controller acting as the I
2
C master.
5.2.3 Functional Description
5.2.3.1 Power Supply
CY4603 uses the same power supply circuit as CY4609 to generate 3.3-V and 1.2-V power supplies.
The design of CY4603 differs from that of CY4609 with respect to the implementation of power con-
trol. CY4603 implementation supports monitoring an overcurrent condition at each downstream port
using a power switch. To reduce the number of power switches, CY4603 uses two dual-channel
power switches (TPS2560DRC) as shown in
Figure 5-12 . Each switch can control two downstream
ports.
These power switches are configured to interrupt the HX3 hub controller when the current drawn by
the connected downstream device exceeds 2.1 A. In response, HX3 immediately shuts down the
power supply (VBUS) to that downstream port by disabling power enable on the corresponding
channel (for example, DS1_PWREN) of the power switch.