3. Adaptive Continuous Resistor for Miller Compensation in IC-LDO Regulators

IC-LDO regulators are circuits that play a key role in modern power management and SoC design. They are required to occupy small area, operate with low power consumption and low supply voltage, and perform fast transient response and good load and line regulations. In addition, they must remain stable under extreme variations of the input voltage, load current and load capacitance. In this chapter, an adaptive and continuous compensation technique is proposed that tunes the value of the zero-nulling resistor of a classical Miller-based compensation to keep the nulling zero close to the Unit Gain Frequency (UGF), according to the working conditions. This technique has been applied to an LDO regulator based on a classical topology. Results of an implementation of such a regulator fabricated in a standard 65 nm CMOS technology are shown at the end of the chapter.