A linear voltage regulator is provided for providing an output voltage to
a load. In a preferred embodiment, the linear voltage regulator
comprises: an operational amplifier receiving a regulated voltage, and a
first voltage reference, and providing a driving voltage; a first
regulating transistor driven by the driving voltage, the regulating
transistor receiving a system voltage, and providing the regulated
voltage; a second regulating transistor receiving the regulated voltage,
and providing an output voltage, the second regulating transistor
controlled by a controlling voltage; a resistive voltage divider
receiving the output voltage, and providing a second voltage reference;
and a three-terminal adjustable shunt regulator receiving the second
voltage reference, and providing the controlling voltage to the second
regulating transistor. Because the first regulating transistor pulls down
the system voltage to the regulated voltage, the operating voltage of the
second regulating transistor is lower than that of a typical linear
voltage regulator, therefore the linear voltage regulator can provide a
high-power to the load.