USB
Regulator
USB
XCVR
USB
Controller
USB0_DP
USB0_DM
VDD
VOUT33
VREGIN
TYPE A
D+
D-
VBUS
2 AA Cells
Cstab
To PMC and Pads
Chip
Figure 3-29. USB regulator AA cell usecase
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.
Chapter 3 Chip Configuration
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
Freescale Semiconductor, Inc. 93