The Design Of Control Circuit For Wide Input On-Chip Charge Pump

Charge pump is a kind of voltage conversion circuit,it has the advantages of small size,easy integration and small electromagnetic interference compared with inductive voltage conversion circuit.Charge pumps are widely used in memory chips,drive chips and various Internet of Things devices because of their good voltage conversion characteristics.However,it is still difficult to balance the voltage conversion efficiency,output ripple and boost speed of charge pumps,and how to keep output voltage of charge pumps stable under a wide range of input voltage is also an important research topic.So the design of charge pump control circuit attracts the attention of many scholars at home and abroad.In this thesis,the characteristics of the common charge pump are analyzed,and the appropriate charge pump core circuit is designed according to the specific application of the project.The advantages and the disadvantages of the existing control method are analyzed,and a scheme of charge pump control circuit suitable for this project is put forward.This scheme by using pulse skip modulation and variable frequency modulation,design a kind of organic combination of the two at the same time with current drive mode.This control circuit not only can make the output voltage stable under wide input voltage,but also can shorten the time of the charge pump booster to the stable output voltage.Based on the CSMC 0.25?m process,the proposed charge pump control circuit is simulated by Cadence.The simulation results show that the charge pump can realize the input voltage range of 2.7V~4.5V through the control,the boost time is less than 90?s,the output voltage is 5V,the error rate is less than 1.7%.The simulation results all realize the design indexes and verify the effectiveness of proposed circuit.