LG U250, Service Manual

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3. TECHNICAL BRIEF
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3.9 Power Block
3.9.1. General
MSM6245, included RF, is fully covered by PM6650(Qualcomm PMIC). PM6650 cover the power of
MSM6245, MSM memory, RF block, Bluetooth, USIM and TCXO. Major power components are :
3.9.2. PM6650
The PM6650 device (Figure 1-1) integrates all wireless handset power management. The power
management portion accepts power from all the most common sources - battery, external charger,
adapter, coin cell back-up - and generates all the regulated voltages needed to power the appropriate
handset electronics. It monitors and controls the power sources, detecting which sources are applied,
verifying that they are within acceptable operational limits, and coordinates battery and coin cell
recharging while maintaining the handset electronics supply voltages.
Eight programmable output voltages are generated using low dropout voltage regulators, all derived
from a common trimmed voltage reference. A dedicated controller manages the TCXO warm-up and
signal buffering, and key parameters (under-voltage lockout and crystal oscillator signal presence) are
monitored to protect against detrimental conditions.
MSM device controls and statuses the PM6650 IC using Single Serial Bus Interface (SSBI)
supplemented by an Interrupt Manager for time-critical information. Another dedicated IC Interface
circuit monitors multiple trigger events and controls the power-on sequence.