Split-feedback technique for improving load regulation in amplifiers

A method of improving load regulation and insuring stability in an amplifier of the type wherein a feedback circuit is deployed, wherein an output from the amplifier feeds an external capacitor having equivalent series resistance (ESR), the method comprising:

• configuring said feedback circuit as a split feedback circuit to include a parallely connected feedback resistance Rf and a feedback capacitance Cf;
• and
• including an intentionally added impedance Resr in the amplifier output, and connecting said Cf to the amplifier output before the Resr and connecting the Rf to the amplifier output after the Resr, whereby said Cf and Rf are connected to opposite ends of said Resr, a junction point of said feedback resistance Rf and said feedback capacitor Cf being connected to a negative input of the amplifier, wherein the amplifier comprises a LDO amplifier, the method including the step of providing an additional resistance (intentional resistance-Rintentional) in series with said resistance Rf.

A scheme for improving load regulation in an LDO amplifier without sacrificing amplifier-stability, comprising:

• a split feedback circuit including a parallely connected DC feedback resistance Rf and a noise reduction AC feedback capacitance Cf, wherein an output from the amplifier feeds an external capacitor having equivalent series resistance (ESR), the scheme comprising:
• including an intentionally added resistance Resr in the amplifier output, and connecting said Cf to the amplifier output before the Resr and connecting the Rf to the amplifier output after the Resr, wherein said Cf and Rf are connected to opposite ends of said Resr, a junction point of said feedback resistance Rf and said feedback capacitor Cf being connected to a negative input of the amplifier and including an additional resistance (intentional resistance-Rintentional) connected in series with said resistance Rf.