Research On A High Efficient DC-DC Converter Of Step Up Down

In many practical application circuit needs fixed output voltage, but input voltage is in change, it let the voltage relationship between the input and output be not sure, in addition wide input voltage and stable output that can satisfy the load. The traditional way is using the Buck-Boost circuit to realize the constant voltage output. Buck-Boost, Sepic, Cuk, Zeta circuit can realize this function, but there are different faults. In view of traditional lifting pressure transducer faults, in the Buck, Boost and having the function of buck-boost converter, the paper research a simple, high efficiency, wide input voltage range of DC-DC buck-boost circuit topology, it can choose the corresponding work mode according to the size of the input and output relationship, divided into buck, boost and step-up mode three modes. Between various patterns in the process of control can realize the switch without a break.This paper simply analyzes the features and disadvantages of these traditional buck-boost converters, clearly indicates the source of the loss of switch power supply, and gives some corresponding solutions. In order to improve the efficiency of this DC-DC converter, on the basis of the buck and boost circuit topology deformation step by step, finally got a can achieve the high efficiency circuit topology, compared with other circuit topology, new converter has the advantages of small volume, high efficiency, and the peripheral circuit. Using synchronous rectifier technology to reduce the power loss on the switch tube in order to improve the efficiency, and all the work modes can realize the OVP, OCP, and short circuit fault protection. This paper introduces the origin of the main circuit and the work process in detail, and analyzes the control theory of all modes. The main circuit`s driving modules connect with three control modules, according to the relationship between input and output confirm the driving signal, and let converter work in the right mode. For the parameter of the main components in the converter has the detailed calculation process, then choose the suitable devices. Through experiments verified the feasibility of the high efficiency step-down voltage circuit, conversion efficiency as high as 97%, obtained the experimental waveforms of Vgs consistent with the theory`s, has reached the preset expectations.