LG KE990 Service Manual - Page 37

3. TECHNICAL BRIEF 3.7 Power Block 3.7.1 General ESM6270, included RF, is fully covered by PM6635(Qualcomm PMIC). PM6635 cover the power of ESM6270, ESM memory, RF block, Bluetooth, SIM and TCXO. Major power components are : PM6635 : Phone power supply AAT3169 : LCD Backlight/Flash charge pump 3.7.2 PM6635 The PM6635 device (Figure 3.7) 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 (undervoltage lockout and crystal oscillator signal presence) are monitored to protect against detrimental conditions. ESM device controls and statuses the PM6635 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. LGE Internal Use Only - 38 - Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes