Voltage regulator with quasi floating gate pass element

A method for regulating a voltage, the method comprising:

• passing a current through an N-channel transistor that is connected between an input and an output of a low dropout voltage regulator;
• generating an error signal based on a voltage of the output;
• capacitively coupling the error signal to a gate of the N-channel transistor;
• comparing the error signal with a reference voltage;
• and
• periodically actuating the switch to charge the gate of the N-channel transistor with a charge pump based at least in part on the comparison of the error signal and the reference voltage.

A low dropout linear voltage regulator comprising:

• an N-channel transistor that is connected between an input and an output of the low dropout linear voltage regulator;
• an error amplifier that is connected to the output through a voltage divider;
• a capacitor that is connected between the error amplifier and a gate of the N-channel transistor;
• a hysteretic comparator that is connected to a node between the error amplifier and the capacitor;
• a charge pump that is connected to the gate of the N-channel transistor through a switch and a current source, wherein the switch and the current source are connected in series between the charge pump and the gate of the N-channel transistor, and wherein the switch is controlled by the hysteretic comparator;
• a second hysteretic comparator connected to the output through the voltage divider;
• a second switch connected between the gate of the N-channel transistor and a ground, wherein the second switch is controlled by the second hysteretic comparator;
• a second current source connected in series with the second switch between the gate of the N-channel transistor and the ground;
• wherein the low dropout linear voltage regulator is adapted to turn on the charge pump and to connect the charge pump to the gate of the N-channel transistor when a voltage at the node between the error amplifier and the capacitor rises above a threshold voltage, and wherein the error amplifier is powered by a voltage source other than the charge pump;
• wherein the low dropout linear voltage regulator is adapted to switch between a floating gate mode of operation when the charge pump is disconnected from the gate of the N-channel transistor and a quasi floating gate mode of operation when the charge pump is connected to the gate of the N-channel transistor;
• and
• wherein the low dropout linear voltage regulator is adapted to have a leakage current that drains a voltage at the gate of the N-channel transistor.