Integrated cmos dc-dc converter implementation in low-voltage cmos technology using ldo regulator

A communications system comprising:

• an alternating current (AC) source;
• a battery charger;
• and
• a cellular telephone comprising:
• a battery adapted to produce a battery voltage;
• and
• a single system on-chip (SoC) integrated circuit chip comprising:
• a low dropout (LDO) regulator operatively connected to said battery and adapted to provide a constant supply voltage from said battery voltage;
• and
• a DC-DC converter operatively connected to said LDO regulator, wherein said DC-DC converter is adapted to step down said constant supply voltage to a lower voltage level.

A method of performing power management of a cellular telephone, said method comprising:

• using a battery to produce a battery voltage;
• operatively connecting a low dropout (LDO) regulator to said battery;
• using said LDO regulator to provide a constant supply voltage from said battery voltage;
• operatively connecting a DC-DC converter to said LDO regulator;
• and
• using said DC-DC converter to step down said constant supply voltage to a lower voltage level,
• wherein said LDO regulator and said DC-DC converter are embedded on a single integrated circuit chip.