3. TECHNICAL BRIEF
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Only for training and service purposes
LGE Internal Use Only
The PMIC accepts power from the usual sources:
An external wall charger – for operating the handset electronics and charging its battery; thePMIC
supports overvoltage protection up to +28 V.
An external USB device – for operating the handset electronics and charging its battery.
The handset’s main battery – the usual power source for operating the handset electronics.
The handset’s coin cell backup or keep-alive capacitor – only used when none of the other power
sources are available; very limited functionality (no handset communications).
The PMIC monitors and controls the power sources, detecting which sources are applied andverifying that they
are within acceptable operational limits, and coordinates battery and coin cell recharging while maintaining the
handset electronics supply voltages. Thermal conditions of the integrated pass transistor and its total current are
monitored and reported to a state machine that coordinates PM operations, including autonomous charging of
the main battery. Software control via the Mobile Station Modem™ (MSM™) or Qualcomm Single-Chip™ (QSC™)
device is also available, identical to previous generation PMICs.
Other input power management circuits provide VDD or VBAT voltage regulation (defined by the PMIC
operating mode), current monitoring and over-current protection, battery voltage alarms with programmable
thresholds, VDD collapse protection, undervoltage lockout protection, and automated recovery from sudden
momentary power loss (SMPL).
On-chip voltage regulators generate 32 programmable output voltages using a combination of 5 switched-
mode power supplies, 26 low-dropout linear regulators, and 1 negative charge pump – all derived from a
common trimmed voltage reference. Key regulators support dynamic voltage scaling (DVS), and most allow low-
power modes to minimize dissipation. Two low-voltage switches are available for gating the power supplies to
external circuits.
The device's general housekeeping functions include input switch matrices and analog multiplexing that selects
from several possible inputs; the selected signal is routed to the on-chip HK/XO ADC. A set of input scaling
circuits extends the acceptable range of input voltages and increases the effective ADC resolution. These circuits
are used to monitor on-chip functions such as the die temperature and bandgap reference voltage, key voltage
nodes (such as VCHG, VBAT, etc.), or system parameters such as temperatures and battery ID.
Various oscillator, clock, and counter circuits are provided to initialize and maintain valid pulse waveforms and
measure time intervals for higher-level handset functions. Four independent XO controller/buffer circuits are
available, allowing individual turn-on, warmup, and deglitched clock sources for MSM, QSC, and RFIC devices,
plus non-phone circuits such as wireless-LAN