Patent ID: 10831221

Abstract:
A low drop-out (LDO) voltage regulator employs combined compensation methods for reduced capacitor area. Frequency compensation internal to a LDO voltage regulator is accomplished by introducing a metal-insulator-metal (MIM) compensation capacitor in series with a compensation resistor between an input to a second stage of the LDO voltage regulator and a regulator output. This achieves a good settling response over a wide range of load conditions at the expense of relatively large capacitor area. Alternatively, a metal-oxide semiconductor (MOS) compensation capacitor may be coupled between an intermediate node of a cascode circuit in a first stage of the LDO voltage regulator and the regulator output. This requires less capacitor area but exhibits instability at some corners. In combination, a good settling response over all corners may be achieved with stacked MIM/MOS capacitors occupying significantly less area than the MIM capacitor of the first method alone.