A Fully-Integrated Current-Mode Type-Ⅲ Buck Converter For Supply Modulation Of NB-IoT PAs

The low power consumption of NB-Io T requires that the terminal should work for more than ten years.The uplink of the terminal transmitter,based on single-carrier frequency-division multiple-access（SC-FDMA）,has a high peak-to-average ratio（PAPR）with 180k Hz maximum bandwidth.Using a traditional DC power supply to power the power amplifier,there is a high dropout between the supply and the envelope singal,which causes additional power loss and reduces the service life of the terminal.In this dissertation,we propose a fully-integrated current-mode Type-III compensator for NB-Io T dynamic power applications to reduce the dropout between the supply and the envelope signal to extend the battery lifetime.Frequency-domain analysis of the current-mode control-to-output transfer function shows that current-mode Type-III compensation achieves an extended bandwidth and a higher bandwidth/switching frequency ratio(f_ugb/f_sw)compared with current-mode Type-II compensation.We discuss the differences between series-type Type-III compensation and parallel-type Type-III compensation.The main focus of this dissertation is series-type Type-III compensation.The circuit implementations of series-type Type-III compensation are detailed in this dissertation.This fully-integrated series-type Type-III compensator is constructed by cascading the A and B modules.The A module is implemented by a common stage,a main amplifier,and an auxiliary high-frequency gain-enhancing amplifier.It provides a low-frequency pole and a zero within the bandwidth to maintain enough gain boosts.The B module is implemented by a band-pass filter.It provides a zero within the bandwidth to maintain enough phase boosts.This proposed compensator reduces the chip area and PAD numbers dramatically compared with the conventional Type-III compensator.Simulated and verified in a 0.13-μm CMOS process.At 5MHz switching frequency(f_sw),this design achieves 1.6MHz unity-gain bandwidth(f_ugb),corresponding to 1/3fugb/fsw ratio.Furthermore,it achieves a settling time of 0.9μs at 400m A load transient and a responding time of 3μs at 450m V reference step.The peak efficiency is 96.7%.It can track up to 180k Hz 0.8Vpp sinusoidal waveforms.