Design Of Low Quiescent Current Transient-enhanced Low Dropout Linear Regulator For 5G IoT Systme

With the rapid development of 5G communication technology,the Internet of Things(Io T)has become a widely concerned field.In the Io T system,various sensors,smart devices,and controllers require stable and reliable power supply.Due to the typically low operating current of Io T devices,it is necessary to use low quiescent current power supply devices to improve system efficiency and extend operating time,thus achieving efficient and stable power conversion.Low Dropout Regulator(LDO)has become one of the main choices for power conversion in Io T systems due to their advantages of low noise,low ripple and low electromagnetic interference.This thesis is based on the5 G Io T system and aims to design a low static current transient-enhanced linear regulator to ensure the low power consumption and stability of the Io T power system.After studying the basic theoretical knowledge of LDO,a low-power transient-enhanced LDO applied in 5G Io T system was designed,which includes modules such as reference voltage source,error amplifier,power transistor feedback stage,adaptive bias compensation circuit,and overtemperature and over-current protection circuits,etc.In order to maintain stability of the system in the full load range,this thesis uses cascode compensation combined with adaptive bias technology loop compensation.To enhance the transient response characteristics of LDO,an overshoot suppression circuit is designed which can effectively prevent the impact of input overshoot voltage on the subsequent circuit and improve its transient response capability.To reduce power consumption,low quiescent current components and circuit structures are used.Finally,the design achieves low quiescent current under light load and good transient response capability under load.In addition,overtemperature and over-current protection circuits are designed to effectively improve the robustness of the circuit.Based on SMIC 0.18 μm CMOS process,this thesis designs a bandgap reference voltage source with a fast start-up circuit that stably outputs a 1.2 V zero temperature coefficient low temperature drift reference voltage at a 3.5V power supply voltage,and its temperature coefficient is 11.88 ppm/℃.The static current consumption of the total circuit is 31.75 μA,among which the bandgap reference circuit is 6.45 μA,the protection circuit is 4.21 μA,and the LDO module circuit is 20.89 μA.The input voltage range is 1.65-3.5 V,which can stably output 1.5 V.Its maximum load capacity is100 m A.Within the entire load current range from no-load to heavy-load,the low-frequency loop gain reaches 98 d B and the worst-phase margin is 87 degrees.The linear adjustment rate is 0.0875 m V/V,the load adjustment rate is 8.49 μV/V,the maximum output voltage ripple in transient response is 130 m V,and the recovery time is within 4.3 μs.The PSR is-62 d B at 1k Hz,and the output load capacitance is 100 p F,which can be integrated directly into the chip without adding external capacitors.