Programmable low dropout regulators with fast transient response when programming output voltage

摘要

Apparatus and methods for programmable low dropout (LDO) regulators for radio frequency (RF) electronics are provided herein. 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.