US 12,645,235 B2 · Voltage regulator with saturation prevention

Abstract

In described examples, a low dropout voltage regulator includes an input voltage terminal, a resistive element, first and second transistors, an output terminal, a differential amplifier, and first and second saturation prevention circuits. The resistive element is coupled between the input voltage terminal and a gate of the first transistor. The output terminal is coupled to the drain of the first transistor and the source of the second transistor. A first input of the differential amplifier receives a reference voltage, and a second input is coupled to the output terminal. The first saturation prevention circuit provides a first clamp current to the differential amplifier output if the gate-source voltage of the first transistor is less than a first threshold voltage. The second saturation prevention circuit provides a second clamp current to the differential amplifier output if the gate-source voltage of the second transistor is greater than a second threshold voltage.

Claims20

Dependent claims

An amplifier comprising:

a first transistor including a current terminal and a control terminal;
a resistive element including a terminal coupled to the control terminal of the first transistor;
a second transistor including a current terminal and a control terminal;
a differential amplifier including an output;
and
a saturation prevention circuit including an input and an output, the input of the saturation prevention circuit coupled to the terminal of the resistive element and to the control terminal of the first transistor, the output of the saturation prevention circuit coupled to the output of the differential amplifier and to the control terminal of the second transistor.

3 more elements

An amplifier comprising:

an input voltage terminal adapted to receive an input voltage;
an output terminal adapted to couple to a load;
a first transistor including first and second terminals and a gate, the first terminal of the first transistor coupled to the input voltage terminal;
a differential amplifier including a first input, a second input, and an output, the first input of the differential amplifier adapted to receive a reference voltage, and the second input of the differential amplifier coupled to the output terminal;
and
a second transistor including first and second terminals and a gate, the gate of the second transistor coupled to the output of the differential amplifier, and the first terminal of the second transistor coupled to the second terminal of the first transistor and to the output terminal;
a first saturation prevention circuit configurable to provide a first current to clamp a voltage at the output of the differential amplifier based on a gate-source voltage of the first transistor being less than a first threshold voltage;
and
a second saturation prevention circuit configurable to provide a second current to clamp the voltage at the output of the differential amplifier based on a gate-source voltage of the second transistor being greater than a second threshold voltage.

6 more elements

Dependencies are inferred from the claim text.

Voltage regulator with saturation prevention

Life of this patent

Voltage regulator with saturation prevention

Life of this patent

Abstract

Claims20