LG KG225, Service Manual

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3. TECHNICAL BRIEF
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E. LDO Block
There are 8 LDOs in the AD6720.
- VCORE : supplies Digital baseband Processor core and AD6720 digital core
- VMEM : supplies external memory and the interface to the external memory on the digital
baseband processor (1,8V or 2.8V, 150mA)
- VEXT : supplies Radio digital interface and high voltage interface (2.8V, 170mA)
- VSIM : supplies the SIM interface circuitry on the digital processor and SIM card
(2.85V, 20mA)
- VRTC : supplies the Real-Time Clock module (1.8 V, 20µA)
- VABB : supplies the analog portions of the AD6720
- VMIC : supplies the microphone interface circuitry (2.5 V, 1 mA)
- VVCXO : supplies the voltage controlled crystal oscillator ( 2.75 V, 10 mA)
3.5 Battery Charging Block
1. It can be used to charge Lithium Ion batteries.
Charger initialization, trickle charging, and Li-Ion charging control are implemented in hardware.
2. Charging Process
- Check charger is inserted or not
- If AD6720 detects that Charger is inserted, the CC-CV charging starts.
- Exception : When battery voltage is lower than 3.2V, the precharge(low current charge mode)
starts firstly.
- And the battery voltage reach to 3.2V the CC-CV charging starts.
3. Pins used for charging
- VCHG : charger supply.
- GATEDRIVE : charge DAC output
- ISENSE : charge current sense input
- VBATSENSE : battery voltage sense input.
- BATTYPE : battery type identification input
- REFCHG : voltage reference output
4. TA (Travel Adaptor)
- Input voltage: AC 85V ~ 260V, 50~60Hz
- Output voltage: DC 5.2V ( 0.2 V )
- Output current: Max 800mA ( 50mA )
5. Battery
- Li-ion battery (Max 4.2V, Nom 3.7V)
- Standard battery: Capacity - 830mAh