LG HB620 Service Manual page 27

3. TECHNICAL BRIEF
3.5.3 Front-End Module (FL101 : LSHS-M090UH)
This equipment uses a single antenna to support all handset operating modes, with an antenna switch
module select the operating frequency and band. UMTS operation requires simultaneous reception and
transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates receive and
transmit signals. The active connection is MSM-selected by three control lines (GPIO[9], GPIO[10], and
GPIO[11]). These GPIOs are programmed to be ANT_SEL0, ANT_SEL1, and ANT_SEL2 respectively.
EGSM TX
DCS/PCS TX
UMTS2100
EGSM RX
DCS RX
3.5.4 PMIC Functional Block Diagram (U401 : PM6650-3P)
■ Input power management
- Valid external supply attachment and removal detection
- Supports unregulated (closed-loop) external charger supplies and USB supplies as input power
sources
- Supports lithium-ion main batteries
- Trickle, constant current, constant voltage, and pulsed charging of the main battery
- Supports coin cell backup battery (including charging)
- Battery voltage detectors with programmable thresholds
- VDD collapse protection
- Charger current regulation and real-time monitoring for over-current protection
- Charger transistor protection by power limit control
- Control drivers for two external pass transistors and one external battery MOSFET - MOSFET is
optional
- Voltage, current and power control loops
- Automated recovery from sudden momentary power loss
LGE Internal Use Only
ANT_SEL0
HIGH
HIGH
HIGH
LOW
LOW
[Table 3.2] Front End Module control logic
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ANT_SEL1 ANT_SEL2
HIGH
LOW
LOW
LOW/HIGH
HIGH
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Only for training and service purposes
LOW
LOW
HIGH
LOW
HIGH