Low dropout regulator with resistive device

A low dropout regulator for providing an output voltage, the low dropout regulator comprising:

• a resistive device configured to contribute to stability of the low dropout regulator during operation and to have a resistance that is dependent on a load current;
• a first resistive element;
• a second resistive element;
• a first amplifier;
• a regulator transistor;
• and
• a first capacitor,
• wherein:
• the first resistive element and the second resistive element are coupled in series;
• the regulator transistor and the first resistive element are coupled at an output node for providing the output voltage;
• the first resistive element and the second resistive element are coupled at a feedback node for providing a feedback voltage, the feedback node being coupled to a second input terminal of the first amplifier;
• the regulator transistor is coupled to a first voltage terminal;
• the second resistive element is coupled to a second voltage terminal;
• the resistive device is directly coupled to the output node, an output terminal of the first amplifier and the first voltage terminal;
• the regulator transistor is directly coupled to the output terminal of the first amplifier;
• the first capacitor is directly coupled to the second input terminal;
• the first amplifier comprises:
• i) a first input terminal for receiving a reference voltage;
• ii) the second input terminal for receiving the feedback voltage;
• and
• iii) the output terminal;
• the regulator transistor comprises a gate terminal coupled to the output terminal of the first amplifier;
• the resistive device comprises further a first negative threshold transistor;
• the resistive device further comprises a first transistor coupled in series with the first negative threshold transistor;
• the first negative threshold transistor comprises a first terminal coupled to the output node and a second terminal coupled to a first terminal of the first transistor;
• the first transistor comprises a second terminal coupled to a first voltage terminal and a gate terminal coupled to the output terminal of the first amplifier;
• and
• wherein the resistive device comprises a second transistor coupled in series with a second negative threshold transistor, the series coupling of the first negative threshold transistor and the first transistor being coupled in parallel with the series coupling of the second negative threshold transistor and the second transistor.

A method of providing an output voltage, comprising:

• providing a low dropout regulator for providing an output voltage, wherein the low dropout regulator comprises:
• a resistive device configured to contribute to stability of the low dropout regulator during operation and to have a resistance that is dependent on a load current;
• a first resistive element;
• a second resistive element;
• a first amplifier;
• a regulator transistor;
• and
• a first capacitor,
• wherein:
• the first resistive element and the second resistive element are coupled in series;
• the regulator transistor and the first resistive element are coupled at an output node for providing the output voltage;
• the first resistive element and the second resistive element are coupled at a feedback node for providing a feedback voltage, the feedback node being coupled to a second input terminal of the first amplifier;
• the regulator transistor is coupled to a first voltage terminal;
• the second resistive element is coupled to a second voltage terminal;
• the resistive device is directly coupled to the output node, an output terminal of the first amplifier and the first voltage terminal;
• the resistive device comprises a first negative threshold transistor;
• the regulator transistor is directly coupled to the output terminal of the first amplifier;
• the first capacitor directly coupled to the second input terminal;
• and
• the first capacitor is directly coupled to the first negative threshold transistor.