Design of a Fast Transient Response and Capacitor-Free LDO Regulator

Based on the working principle of LDO regulator, a fast transient response and capacitor-free LDO regulator was designed. LDO regulator includes bandgap reference without amplifier、EA、transient response enhancement module、power regulator and NMOS transistor feedback network. A new structure of the transient response enhancement circuit is proposed to speed up the power adjustment transistor gate charge and discharge, and realize the fast transient response. The circuit is fabricated with TSMC 0.18μm CMOS process and has the layout size of 190 μm×210 μm. The simulation results show that when the input voltage is 3.3 V, the output voltage is 2.15 V. Between light load and full load establishment of the maximum time for the 0.6 μs. PSRR is -63 dB at low frequency, voltage difference is 50 mV.