The utility model discloses a circuit structure for improving the stability of LDO, including low dropout
linear regulator circuit and low dropout
linear regulator circuit connected negative
capacitance generation circuit, low dropout
linear regulator circuit includes adjusting tube and first
amplifier, the output end of first
amplifier is connected with the gate of adjusting tube, the output end of first
amplifier is connected with the gate of adjusting tube, the output end of first amplifier is connected with the gate of adjusting tube, and the negative
capacitance generation circuit is connected with the negative
capacitance generation circuit in the low dropout linear
regulator circuit. The first amplifier is an
error amplifier; according to the technical scheme provided by the utility model, besides a known method for increasing the
pole frequency of an internal node by adding source follower isolation, a new method is provided for increasing the
pole frequency of the internal node, and by utilizing the Miller principle, a negative capacitance generation circuit in the low-dropout linear
voltage regulator circuit is adopted, so that the high-
voltage linear
voltage regulator can be used for increasing the
pole frequency of the internal node. Therefore, an equivalent
capacitor with a reduced capacitance value is formed, so that the
time constant of a node at the joint of the
error amplifier and the adjusting tube is reduced, the pole frequency is increased, an output port can be changed into a dominant pole, the
phase margin of the LDO is improved, and the stability of the LDO is ensured.