The present invention provides a low dropout (LDO) regulator with a
stability compensation circuit. A "zero frequency" tracking as well as
"non-dominant parasitic poles' frequency reshaping" are performed to
achieve a good phase margin for the LDO by means of the compensation
circuit. In this compensation method neither a large load capacitor nor
its equivalent series resistance is needed to stabilize a regulator. LDO
regulators, in system on chip application, having load capacitors in the
range of few nano-Farads to few hundreds of nano-Farads can be
efficiently compensated with this compensation method. A dominant pole
for the regulator is realized at an internal node and the second pole at
an output node of the regulator is tracked with a variable capacitor
generated zero over a range of load current to cancel the effect of each
other. A third pole of the system is pushed out above the unity gain
frequency of the open loop transfer function with the help of the
frequency compensation circuit. The compensation technique is very
effective in realizing a low power, low-load-capacitor LDO desirable for
system on chip applications.