Voltage regulating circuit

A voltage regulating circuit, comprising:

• a reference voltage generator, comprising a comparator, a first control switch and an impedance, wherein the first control switch and the impedance are serially connected between a power voltage and a ground voltage, wherein a first current is fed from the first control switch to the impedance to produce a feedback voltage on a terminal of the impedance, the feedback voltage is fed back to the comparator for comparison with a reference voltage, and the comparator produces a control voltage to control the first control switch for adjusting the first current;
• a compensating circuit, comprising a negative threshold voltage transistor and a second control switch, wherein the negative threshold voltage transistor and the second control switch are serially connected between the power voltage and feedback voltage, wherein the negative threshold voltage transistor is turned on only when an operational condition of the voltage regulating circuit is at a fast-fast corner (FF), wherein the control voltage controls the second control switch to generate a second current added to the first current and fed into the impedance;
• and
• an output circuit, comprising a third control switch and a fixed current source, wherein the third control switch and the fixed current source are serially connected between the power voltage and the ground voltage, wherein the control voltage controls the third control switch to generate a regulating voltage between the third control switch and the fixed current source.