Cypress CY4603, User Manual, Page: 33 / 94

HX3 Kits User Guide, Doc. #: 001-91203 Rev. *D 33
Kit Operation
3.4.5 Ghost Charging
Disconnect the USB cable from the upstream port to detach the board from the PC, as shown in
Figure 3-21 . The board continues to charge the device connected to the downstream port using the
Ghost Charging feature.
Notes:
■
While the board is switching to the Ghost Charging mode, it stops charging the device connected
to the downstream port momentarily and resumes charging within 1 to 2 seconds.
■
The current drawn by the device in Ghost Charging mode may vary compared to the current
drawn in normal Battery Charging mode.
Figure 3-21. Ghost Charging
According to the USB-IF Battery Charging specification v1.2, charging downstream ports (CDPs) are
expected to provide 1.5-A current (typical) per port. The power adapter shipped with CY4609 and
CY4603 supports up to 4 A of load current. After calculating the power consumed by HX3 and other
parts of the board, 3.6 A is available to support charging on the downstream ports. When the board
is used with the 5-V/4-A power adapter, ensure that no more than two downstream ports are used as
CDP. If the current consumed by the downstream ports exceeds 3.6 A, the CY4609 board detects an
overcurrent condition and interrupts HX3, which disables power to all the downstream ports until the
overcurrent condition is removed and the board is reset.
Disconnect the USB cable f
from the upstream port