To provide a method and a circuit for obtaining a low-dropout voltage regulator having constant and high performance in all operating conditions including a dropout region.
This method includes: a step for providing an amplifier, a transistor located at the output of the amplifier, a voltage divider, a current mirror, a regulation cascode structure and a supply voltage; a step 51 for sensing an output voltage by positive input of the cascode structure; a step 52 for sensing the input voltage of the current mirror by negative input of the cascode structure; a step 53 for disposing the regulation cascode at the input of the current mirror; a step 54 for regulating the input voltage of the current mirror so as to set it equal to the output voltage in all the operation conditions; a step 55 for keeping the current mirror at a matching operation point; a step 56 for keeping a constant high regulator loop gain; and a step 57 for keeping a PSRR and a load regulation gain high even in all the operating conditions.
Tadashi Masui
Yasushi Kobayashi
Akio Chiba
Hiroyuki Tomita
Fumitoshi Nishiyama