Voltage regulator

1. A voltage regulator comprising:

a reference voltage circuit for outputting a reference voltage;

an output transistor;

a first differential amplifier circuit for amplifying and outputting a difference between the reference voltage and a divided voltage obtained by dividing voltage output from the output transistor to control a gate of the output transistor;

a booster circuit for detecting output current from the output transistor and outputting a signal to the first differential amplifier circuit,

wherein the booster circuit performs control operations to increase a bias current flowing through the first differential amplifier circuit according to an output current from the output transistor, and increases a response time of the first differential amplifier circuit;

a sensing transistor having a gate connected to an output of the first differential amplifier for sensing the output current;

a first transistor having a source connected to a drain of the sensing transistor and to the booster circuit for making an adjustment to enable the output current to be copied accurately by the sensing transistor; and

a second differential amplifier circuit in which an output terminal is connected to a gate of the first transistor, an inverting input terminal is connected to the drain of the sensing transistor, and a non-inverting input terminal is connected to an output terminal of the voltage regulator.

2. The voltage regulator according to claim 1 , wherein the booster circuit includes:

a second transistor in which a gate is connected to a drain and a gate of a third transistor, a drain is connected to a gate and a drain of a fourth transistor, and a source is connected to a first resistor;

a fifth transistor in which a drain is connected to the drain of the third transistor, and a gate and a source are connected to the gate and source of the fourth transistor, respectively;

the fourth transistor whose gate and drain are connected to the drain of the second transistor;

the third transistor whose source is connected to a ground; and

the first resistor connected to the source of the second transistor,

whereby a resistance value of the first resistor is adjusted to adjust a value of a load current to be detected.

3. The voltage regulator according to claim 1 , wherein the booster circuit includes:

a second transistor whose gate is connected to an output of a third differential amplifier circuit;

a third transistor in which a gate and a drain are connected to a source of the second transistor and an inverting input terminal of the third differential amplifier circuit, and a source is connected to a ground; and

the third differential amplifier circuit whose non-inverting input terminal is connected to a second reference voltage circuit,

whereby a voltage value of the second reference voltage circuit is adjusted to adjust a value of a load current to be detected.

4. The voltage regulator according to claim 1 , wherein the booster circuit includes:

a second transistor whose gate is connected to an output of a third differential amplifier circuit;

a third transistor whose gate and drain are connected to a first terminal of a first resistor; and

the third differential amplifier circuit in which a non-inverting input terminal is connected to a second reference voltage circuit, and an inverting input terminal is connected a source of the second transistor and a second terminal of the first resistor,

whereby a resistance value of the first resistor is adjusted to adjust a value of a load current to be detected.