Power Block - LG U310 Service Manual

3. TECHNICAL BRIEF

3.10.3. Power Block

3.10.3.1. General
MSM6250A, included RF, is fully covered by PM6650-2M(Qualcomm PMIC). PM6650-2M cover the
power of MSM6250A, MSM memory, RF block, Bluetooth, Trans flash, USIM and TCXO.
Major power components are :
PM6650-2M(U400) : Phone power supply
BH28FB1WHFV(U505) : LCD Power supply
QST4(Q400,Q401) : External charger supply switching
SI3493DV(Q402) : Main Battery charging control
R1114D281D(U502/U504) : Camera power supply
3.10.3.2. PM6650-2M
The PM6650-2M 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 PM6650-2M IC using a three-line Serial Bus Interface (SBI)
supplemented by an Interrupt Manager for time-critical information. Another dedicated IC Interface
circuit monitors multiple trigger events and controls the power-on sequence.
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