Voltage Regulation; Internal Regulation; External Regulation - LG U8130 Service Manual

3. TECHNICAL BRIEF

3.5 Voltage Regulation

3.5.1 Internal Regulation

There are LDO (Low Drop Output) regulators and BUCK converter in AB2000 (Vincenne) chip. LDO
regulators and BUCK converter generate the following voltages : 1.5V, 1.8V and 2.75V. The output of
these LDOs supply VDD-A, VDD-B and VDIG with 2.75V. BUCK converter steps down the VBAT to
1.5V for VCORE and VRTC, and to 1.8V for VMEM voltage. The output of these LDOs and BUCK
converter are as following Table. Figure shows the power supply of each module in U8100.

3.5.2 External Regulation

1.5V LDO - supply 1.5V for wanda core
2.8V LDO - supply 2.8V for IrDA
2.8V LDO - supply 2.8V for Camera
3.3V LDO - supply 3.3V for USB
4.5V DC-DC converter – supply 4.5V for LCD back light
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