LG KS20 Operating Instructions Manual page 25

3.5.4 PMIC Functional Block Diagram (U304 : PM7540)
• Complete power management, housekeeping, and user interface functions for wireless devices (CDMA,
non-CDMA handsets, and PDAs)
• 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
• Output voltage regulation
- One boost (step-up) switched-mode power supply (SMPS) for driving white LEDs and hosting USB-OTG
- Four buck (step-down), switched-mode power supplies for efficiently generating MSMC1, MSMC2,
MSME, and PA supply voltages
- Supports dynamic voltage scaling (DVS) for MSMC1, MSMC2, and PA outputs
- 18 low-dropout regulator circuits with programmable output voltages, implemented using three different
current ratings: 300 mA (four), 150 mA (ten), and 50 mA (four). These can be used to power MSMA,
MSMP, MSME2, MMC, RFRX1, RFRX2, RFTX, TCXO, SYNT, RUIM1, RUIM2, USB, WLAN, MDDI,
CAM, BT, AUX1, and AUX2 circuits.
- One MIC bias regulator circuit
- All regulators can be individually enabled/disabled for power savings
- Low power mode available on most regulators
- All regulated outputs are derived from a common bandgap reference (close tracking)
• Integrated handset-level housekeeping functions reduces external parts count, size, and cost
- Analog multiplexer selects from five internal and up to 28 external inputs
- Multiplexer output's offset and gain are adjusted, increasing the effective ADC resolution
- Adjusted multiplexer output is buffered and routed to an MSM device ADC
- Dual oscillators: a 32.768 kHz off-chip crystal and an on-chip RC assure MSM device sleep clock
- Crystal oscillator detector and automated switch-over upon lost oscillation
- Real-time clock for tracking time and generating associated alarms
- On-chip adjustments minimize crystal oscillator frequency errors
- Control TCXO warm-up and synchronize, deglitch, and buffer the TCXO signal
- TCXO buffer control for optimal QPH/catnap timing
- Multistage over temperature protection (smart thermal control)
• Integrated handset-level user interfaces
- Four programmable current sinks recommended as keypad backlight, LCD backlight, camera flash, and
general-purpose drivers
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
3. TECHNICAL BRIEF
- 27 -
LGE Internal Use Only