Research And Design Of Wide Input-Output High Efficiency Four-Switch Buck-Boost Converter

With the continuous development of electronic technology,semiconductor technology and integrated circuit technology.Various electronic devices are increasingly used,which puts forward higher requirements for switching power supply chips.As much as possible to improve the conversion efficiency of the power management system,improve the overall stability of the power system,and reduce the integration area of the power system will be the general trend of power management research.In many practical electronic applications,a stable and safe input voltage source is required.The power management chip can provide a stable input voltage source for electronic products by converting an unstable external power supply.At the same time,the research and design of a class of power management chips with high efficiency and wide voltage application range are of great significance to the future development needs of the electronic product market.This thesis analyzes the characteristics and shortcomings of conventional buck-boost converters,and takes the traditional boost circuit and the traditional buck circuit principle as the basic technical principles,and equivalently transforms on the basis of the basic circuit topology.Single-inductor circuit topology to achieve buck-boost function.Compared with the circuit topology of conventional buck-boost converter,this converter has more conversion applications and more flexible output voltage conversion.Using synchronous rectification technology to reduce the power loss on the switch to improve the overall efficiency.Through analysis and research on the existing converter control methods,the design chip uses a current-mode voltage-mode dual-loop control system.This control method improves the control capability of the output voltage and changes in the output load current while ensuring stability responding speed.The chip integrates a power tube to ensure that the product has a smaller size and is easier to use in portable electronic products.In addition,under light load conditions,control methods such as cycle skip mode and burst mode are used to reduce losses.The high-efficiency four-switch buck-boost DC-DC converter chip designed in this paper adopts 0.35μm BCD process.Using Cadence as the software simulation platform in the Spectre simulation environment,the whole chip and each sub-module were simulated.The simulation results show that the designed converter can normally achieve a wide output voltage of 0.8V to 36V in a wide input power supply voltage range of 4 to 36V,the output voltage error is less than 1.2%,and the reference voltage adjustment rate is less than 0.02%.At the same time,the simulation results prove that the converter can work within the operating frequency range of 300kHz,and can provide a 4A load current steadily.The load regulation rate is less than 0.8%when the load current jumps.Under light load conditions,the skip cycle mode can be achieved.In addition,the chip also integrates the input voltage protection and output voltage detection module to ensure the safe operation of the chip in a wide voltage range.The chip can be used in many fields such as automotive electronics,telecommunications systems and industrial control.