Information

3.9.1.2.2 Li-Ion battery power supply
The chip can also be powered by a single Li-ion battery. In this case, VOUT33 is
connected to VDD. The USB regulator must be enabled by default to power the MCU.
When connected to a USB host, the input source of this regulator is switched to the USB
bus supply from the Li-ion battery. To charge the battery, the MCU can configure the
battery charger according to the charger detection information.
USB
Regulator
USB
XCVR
USB
Controller
USB0_DM
USB0_DP
VDD
VOUT33
VREGIN
TYPE A
D+
D-
VBUS
C
stab
To PMC and Pads
Chip
Charger
Detect
VBUS Sense
VSS
Charger
Li-Ion
Si2301
Figure 3-43. USB regulator Li-ion usecase
3.9.1.2.3 USB bus power supply
The chip can also be powered by the USB bus directly. In this case, VOUT33 is
connected to VDD. The USB regulator must be enabled by default to power the MCU,
then to power USB transceiver or external sensor.
Communication interfaces
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
114 Freescale Semiconductor, Inc.