Design of high-performance voltage regulators based on frequency-dependent feedback factor

A novel scheme is presented for achieving high performance low-dropout (LDO) voltage regulators under the constraint of low supply voltage. This scheme makes use of a frequency-dependent feedback factor (FDFF). The FDFF has simple circuit structure and frequency-dependent gain. When it is used in the proposed LDO, the low voltage operation ability, wide-band high power-supply rejection (PSR) characteristic and excellent transient response performance can be obtained. Simulation results show that this LDO can work properly at 1.2-V supply voltage, and the overshoot is only ImV, while the PSR is better than -40dB from dc to 100-MHz. Therefore, the FDFF based LDO is well suited for low-voltage ripple-sensitive applications. ? 2007 IEEE.EI