LG KE990 Service Manual - Page 21

3. TECHNICAL BRIEF 3.4.3 PMIC Functional Block Diagram (U501 : PM6635-3P) ■ 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 ■ Output voltage regulation - One boost (step-up) switched-mode power supply (SMPS) for driving white LEDs and hosting USBOTG - Three buck (step-down) switched-mode power supplies that efficiently generate ESMC, ESME, and PA (or second ESMC) supply voltages - Supports dynamic voltage scaling (DVS) for ESMC and PA - Eleven low dropout regulator circuits with programmable output voltages, implemented using three different current ratings: 300 mA (two), 150 mA (six), and 50 mA (three). These can be used to power ESMA, ESMP, RFRX1, RFRX2, RFTX, SYNT, TCXO, WLAN, MMC, USB, and RUIM circuits. - All regulators can be individually enabled/disabled for power savings - Low power mode available on ESMA and ESMP regulators - All regulated outputs are derived from a common bandgap reference - close tracking LGE Internal Use Only - 22 - Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes