Research And Design Of Core Sub-circuits In Charge Pump DC/DC Converter

Power supply is necessary for modern electronic product and it has important meaning for improving the overall performance of electronic product. With the development of miniaturization and low cost of electronic product, small size, high efficiency, low power consumption, high reliability, low noise and integration are becoming the development trend of Switching Power Supply.In this paper, an efficient, high-frequency Charge Pump DC/DC Switching Power Supply circuit is presented. Frist, Types and the basic principles of Switching Power Supply are introduced. Advantages and disadvantages of Low Dropout Regulator, Inductance Switching Power Supply and Capacitance Switching Power Supply are compared in detail. The step-up and the step-down principle of Charge Pump DC/DC Converter Circuit are focused on. According to the application requirements, the overall topology of the chip is designed and module block is divided and core sub-circuits are designed. Bandgap reference provides reference voltage for the accurate output. The latch comparator improves circuit accuracy and reaction speed, and comparing the feedback signal and reference voltage to stabilize output. Constant current sources are used to charge and discharge capacitor, so the oscillation frequency is supply-independent. Over-temperature protection circuit and under voltage lock out circuit implement protection.Based on UMC 0.6μm 2P2M BCD process and Synopsys Inc. HSPICE simulation software, the sub-circuit is simulated. Simulation results meet the desired objectives, in line with the Charge Pump Circuit design theory, and the design is the result of a combination of theory and practice. This effort lays the foundation for follow-up work and accumulates more experience to design Charge Pump Circuit with more perfect performance for the future.