Dual loop push-pull feedback linear regulator for embedded DC-DC converter

In this paper a novel method for fast transient low power and high dropout DC-DC converter for embedded applications has been proposed. Fast transient is achieved by introducing one fast current control feedback loop with relatively slow current control feedback loop with a small Miller capacitor. Inner feedback loop is made faster by utilizing proposed push-pull structure of linear regulator. To ensure stability over a wide range of load current, internal pole is made dominant as compared with the output pole. In addition, an approximate small signal analysis of proposed current control regulator has been done in this paper. The push-pull current control regulation scheme is implemented in 0.18μm CMOS process for 3.3V to 1.35V conversion. Converter uses 50pF load capacitor, 500fF Miller capacitor and support up to 26mA load current. The quiescent current of the converter is 200μA in 3.3V supply voltage without output current.