Analysis And Design Of Wide Input Voltage Large Current Fast Response LDO Liner Regulator

With the rapid development of electronic products,the innovation of power management technology is more and more important,and linear regulators as an important branch of the power management chip,due to low power consumption,low ripple,smaller package area and less peripheral Devices are widely used in portable electronic devices.The small input voltage range of the traditional LDO has limited the application of the linear voltage regulator,and the wide input voltage range of LDO has become a hot topic in the present research.Based on the research trend and hot spot of today's linear regulators,a LDO linear regulator with wide input and high current response is designed after summarizing the previous research contents.The input voltage is 2.5V-20V,the adjustable output voltage is0.8V-20V,and the maximum load current is 3A.The PMOS regulator is used for single-supply operation to realize low leakage voltage.The leakage voltage under the load of 3A is 158mV.The low leakage voltage effectively improves the efficiency of the LDO linear regulator.At the same time,we designed the pre-modulation circuit with V_ddd to generate power for multiple module circuits,achieving low power consumption of the system.Then using a level shift circuit to realize voltage conversion,and the generated high-level signal is transmitted to the error amplifier.By folding two stage operational amplifier as a high gain error amplifier circuit,while improving the performance index of LDO,the linear adjustment of 0.13%/A load adjustment rate and the rate of0.003%/V.Miller resistors and capacitors compensate to make the loop produce two poles and one zero,which ensures the stability of the LDO in the full load range.A new current protection circuit is designed to achieve a negative variable current limit with input and output voltage difference.When the input and output voltage difference is greater than 8V,the current limit decreases from 3.8A to 0.8A under high voltage,which reduces the power consumption of the system under high input voltage and avoids the regulator tube to be damaged by high temperature.Each simulation result of the system meets the design index.In addition,a transient boost circuit is added.When the load jumps,the main loop has no time to respond.By adding a small loop,the feedback voltage is compared with the reference voltage,and then the gate voltage of the regulator tube is adjusted to change the current on the regulator tube.Reduced output voltage jumps while reducing response time.In order to ensure the normal work of the system,the over-temperature protection circuits and the under voltage lockout circuit have also been added.