Wide input voltage range low-power charge pump based ldo

A method of providing a low-drop out regulated voltage, comprising:

• producing a pulse chain at a variable frequency related to a voltage difference between a regulated voltage and a reference voltage;
• driving a charge pump circuit with the pulse chain to provide a charge pump output voltage;
• and
• feeding the charge pump output voltage to the gates of MOS transistors in a current mirror circuit including a first MOS transistor with a first terminal connected to its gate and a second terminal coupled to a supply voltage through a resistor, and a second MOS transistor coupled between the supply voltage and an output capacitor.

An integrated circuit comprising:

• a low-dropout linear regulator comprising:
• a voltage-to-frequency circuit including a first input receiving a reference voltage, a second input, and an output providing a pulse chain at a frequency related to a voltage difference between the first and second inputs;
• a charge pump circuit receiving the pulse chain and switching one or more charge pumps based on the pulse chain to provide a charge pump output voltage;
• and
• a current mirror circuit including:
• a first metal-oxide semiconductor (MOS) transistor having a first terminal coupled to a supply voltage through a resistor, a second terminal connected to the charge pump output voltage, and a gate connected to the second terminal;
• and
• a second MOS transistor having a first terminal connected to the supply voltage, a second terminal providing an output connected to a positive terminal of an output capacitor and to the second input of the voltage-to-frequency circuit, and a gate connected to the gate of the first LDMOS transistor.