Series voltage regulator with low dropout voltage and limited gain transconductance amplifier

A portable communication apparatus comprising a voltage regulation circuit that includes:

• a transconductance amplifier based on a pair of MOS differential transistors, said amplifier comprising a first input into which a reference potential is input and a second input into which a counter-reaction of said regulated voltage is input;
• a follower stage connected to the output of said transconductance amplifier;
• a MOS transistor that outputs a regulated voltage, the MOS transistor comprising a source, a drain, and a gate, the source of the MOS transistor connected to a power supply potential;
• wherein said transconductance amplifier comprises a resistive load with a profile in K/gm, where gm corresponds to the transconductance coefficient of said differential input pair, said resistive load being connected to said first power supply potential.

A voltage regulation circuit comprising:

• an output transistor having a control terminal, a first conduction terminal, and a second conduction terminal;
• a counter reaction circuit connected to the first conduction terminal of the output transistor;
• a transconductance amplifier having a gain of K and a transconductance coefficient of gm, the transconductance amplifier having a first input, a second input, and an output, the first input having a reference potential applied thereto, the second input being coupled to the counter reaction circuit, the output being coupled to the control terminal of the output transistor;
• and
• a resistive component connected to the output of the transconductance amplifier and connected to the second conduction terminal of the output transistor, wherein the resistive component has a profile that is approximately K/gm.

A method of regulating voltage, the method comprising:

• applying a first reference potential to a first electrode of a differential amplifier, the differential amplifier having a transconductance coefficient of gm and a gain of K;
• applying a portion of a regulated output potential to a second input electrode of the differential amplifier;
• providing an output of the differential amplifier to a follower component;
• and
• limiting the output of the differential amplifier with a resistive component connected to an output of the differential amplifier and connected to a first electrode of an output transistor, wherein a second electrode of the output transistor is connected to the second electrode of the differential amplifier, and wherein a gate of the output transistor is coupled to an output of the follower component.