Voltage regulator

1 . A voltage regulator, comprising:

an amplifier circuit, comprising a non-inverting input node, an inverting input node, a first output node, and a second output node, wherein the non-inverting input node receives a reference voltage, and the inverting input node receives a feedback voltage;

a first output stage circuit, coupled to the first output node and the second output node of the amplifier circuit;

a switching circuit;

a clamping circuit, comprising:

a first diode device, an anode node of the first diode device is coupled to a first voltage;

a first switch, a first node of the first switch is coupled to the first output node of the amplifier circuit, a second node of the first switch is coupled to a cathode node of the first diode device, and a control node of the first switch receives a control signal;

a second diode device, a cathode node of the second diode device is coupled to a second voltage; and

a second switch, a first node of the second switch is coupled to the second output node of the amplifier circuit, a second node of the second switch is coupled to an anode node of the second diode device, and a control node of the second switch receives the control signal,

wherein the clamping circuit is coupled to the first output node and the second output node of the amplifier circuit,

wherein the clamping circuit is controlled by the control signal; and

at least one second output stage circuit, coupled to the first output stage circuit in parallel through the switching circuit, wherein the switching circuit is controlled by the control signal,

wherein an output current of the voltage regulator is provided by the first output stage circuit and at least one second output stage circuit selected by the control signal,

wherein transistors in the first output stage circuit and the at least one second output stage circuit have different aspect ratios,

wherein a first aspect ratio of the transistors in the first output stage circuit is less than a second aspect ratio of the transistors in the at least one second output stage circuit, and the second aspect ratio of the transistors in the at least one second output stage circuit is less than a third aspect ratio of the transistors in the at least one second output stage circuit.

2 . The voltage regulator of claim 1 , wherein the voltage regulator is applied to a display system, and the display system includes a power-on period, a display update period, a power switch time period, and a power-off period,

wherein the control signal is enabled in the power-on period and in the power switch time period,

wherein in response to the control signal being enabled, one of the at least one second output stage circuit is selected, and the output current of the voltage regulator is provided by the first output stage circuit and the selected one of the at least one second output stage circuit.

3 . The voltage regulator of claim 2 , wherein the control signal is disabled in the display update period and the power-off period,

wherein in response to the control signal being disabled, the at least one second output stage circuit is not selected, and the output current of the voltage regulator is provided by the first output stage circuit.

4 . The voltage regulator of claim 1 , wherein the control signal comprises:

a first sub-control signal, wherein the selected one of the at least one second output stage circuit which is coupled to the first output stage circuit in parallel is controlled by the first sub-control signal; and

a second sub-control signal, wherein the clamping circuit is controlled by the second sub-control signal.

5 . The voltage regulator of claim 1 , further comprising:

a feedback circuit, a first node of the feedback circuit is coupled to an output node of the voltage regulator which carries the output current of the voltage regulator, and a second node of the feedback circuit is coupled to the inverting input node of the amplifier circuit.

6 . The voltage regulator of claim 5 , wherein the feedback circuit is a voltage dividing circuit.

7 . The voltage regulator of claim 1 , wherein the amplifier circuit is an operational amplifier.

8 . The voltage regulator of claim 1 , wherein each of the first output stage circuit and the at least one second output stage circuit comprising:

a first branch transistor, wherein a first node of the first branch transistor is coupled to the first voltage, a second node of the first branch transistor is coupled to an output node of the voltage regulator; and

a second branch transistor, wherein a first node of the second branch transistor is coupled to the second voltage, a second node of the second branch transistor is coupled to the output node of the voltage regulator.

9 . The voltage regulator of claim 8 , wherein a control node of the first branch transistor in the first output stage circuit is coupled to the first output node of the amplifier circuit,

a control node of the second branch transistor in the first output stage circuit is coupled to the second output node of the amplifier circuit.

10 . The voltage regulator of claim 8 , wherein a control node of the first branch transistor in the at least one second output stage circuit is coupled to the first output node of the amplifier circuit through the switching circuit,

a control node of the second branch transistor in the at least one second output stage circuit is coupled to the second output node of the amplifier circuit.