PROGRAMMABLE LOW DROPOUT REGULATORS, POWER AMPLIFIER SYSTEM, AND METHOD OF VOLTAGE REGULATION IN PROGRAMMABLE LOW DROPOUT REGULATOR

摘要

PROBLEM TO BE SOLVED: To provide apparatus and methods for programmable low dropout (LDO) regulators for radio frequency (RF) electronics.SOLUTION: In certain configurations, an LDO regulator for generating a programmable output voltage includes a regulation field-effect transistor (FET) having a drain electrically connected to the LDO regulator's output, an error amplifier that controls a gate of the regulation FET, a feedback circuit that provides a feedback signal to an inverting input of the error amplifier, an output capacitor electrically connected to the LDO regulator's output, and an alternative discharge circuit. When the output voltage of the LDO regulator is programmed from a high voltage level to a low voltage level, the alternative discharge circuit activates to discharge the output capacitor to improve the LDO regulator's transient response.SELECTED DRAWING: Figure 5A