Abstract:In order to solve the low power and fast transient response problem of LDO without off-chip capacitance, a transient enhancement LDO circuit based on feedforward compensation was proposed. The error amplifier uses a recycling folded cascode amplifier, which has low power consumption and high gain. The feedforward compensation is implemented by connecting multiple small gain stages, which improve the system stability with low quiescent current. The output voltage is coupled to the transient enhancement circuit through capacitors, providing a charging and discharging path for the power transistor to improve the transient response performance. The circuit is designed based on the SMIC 180 nm CMOS process, the simulation results show that after the LDO transient enhancement within the load current jumping range of 100 μA to 50 mA. The output voltage overshoot is reduced by 343 mV, or about 39%, the output voltage undershoot is reduced by 592 mV, or about 57% . The load regulation is 0.005 7 mV/mA and the line regulation is 0.22 mV/V. The quiescent current of the circuit is about 3 μA, and the LDO current efficiency is 99.99%.