Low Drop Out Voltage Regulator

摘要

A low dropout voltage regulator (LDO) is presented that takes into consideration short channel effects of the pass transistor in suppressing ripples that are present at the input node of the LDO from appearing at the output node of the LDO. The LDO feeds the input ripple voltage to the gate of the pass transistor in such a way that the ripple currents through the pass transistor associated with both the transconductance and the output resistance of the pass transistor are suppressed. In one embodiment, the LDO is provided stability by using only on-chip capacitors. The size of on-chip capacitors is advantageously reduced by connecting a compensation capacitance to an internal node of an error amplifier. The LDO provides stable operation even at small load currents. The LDO also provides good suppression of ripples for a wide range of frequencies.