3. TECHNICAL BRIEF
3.9 Power Block
3.9.1 General
The MSM8x55 device is powered by a Qualcomm powerOne™ series PM8058™ power
management IC. The power source is selected from either the battery, external charger, adaptor, or
USB device, and then the IC generates all the regulated voltages needed to power the handset
electronics. The main battery and backup coin-cell voltages are monitored, and charging is
conducted as needed.
In addition to these basic power functions, the PMIC also provides:
Housekeeping functions
Analog multiଝ plexer and ADC that allows monitoring of IC-level and handset-level sensors, including
the XO thermal status
System clocks, including the MSM IC’s 3ଝ 2 kHz sleep clock and 19.2 MHz operating clock
Realtime clock and associated alarmsଝ
User interfaces
Cuଝ rrent drivers for an auto trickle-charge indicator LED
Pulse generator output for controlling external LED and backlight driversଝ
ଝ Vibration motor driver for silent incoming call alerts
Twoଝ -channel (stereo, 500 mW per channel) speaker driver for far-field speakers
Headset send/end detection and microphone biasingଝ
IC-level interfaces
Monitoring of triggering ଝ events and coordination of the poweron and poweroff sequences
Level translators for dualଝ -voltage UIM support
PA ଝ controllers
Major power components are :
PM8058 : Phone main PMIC
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