Voltage regulator circuitry is provided. The voltage regulator circuitry
may contain a drive transistor that is controlled by the output of an
operational amplifier. The drive transistor may supply a regulated
voltage to a load. The operational amplifier may compare a reference
voltage and a feedback signal at its inputs. The operational amplifier
may include first and second stages. An adjustable resistor may be
provided between the first and second stages. Control circuitry may
control the resistance of the adjustable resistor based on the amount of
current flowing through the load to ensure stable operation of the
voltage regulator circuitry. Overshoot and undershoot detection and
compensation circuitry may compensate for overshoot and undershoot in the
regulated voltage. Voltage ramp control circuitry may be used to control
the ramp rate of the regulated voltage.