A Buck_boost Switch Power Supply Circuit Design And Simulation

With the rapid development of the Wireless network communication technology, DC/DC converter has been widely used in the remote control and digital communications fields.Thus, DC/DC converter technology has also been more requested. And high frequency, high power density, small size, rapid response, high reliability and diversity have become the development trends for DC/DC converter.This paper discussed the design and simulation of a kind of Buck_Boost DC/DC converter’s sub-circuit, and have analysed this subject in the sub-circuit modules. And elaborated principles and parameters of the error amplifier circuit, the PWM comparator circuit,the oscillator circuit, the slope compensation and the current detection circuit more detailed, gave the simulation results of a typical situation and made a detailed analysis. Among them, the error amplifier and the oscillator circuit are two core parts of the entire circuit, their designs are the keys to the design of the entire DC/DC converter. Overall, the design of error amplifier consists of two main steps:The first step is the choice of architecture, and the second is the optimization of design parameters. Oscillator circuit using RC oscillator, the oscillation circuit is divided into three parts: The first part is the sinusoidal oscillation circuit using RC ring vibrator, introduced the RC circuit as a delay loop in the simple ring oscillator circuit, and finally formated the RC ring vibrator device. The second part is to produce a square wave, in this part the sine wave change into square wave through a NAND gate and then a INV gate. The third part is a triangle wave. The whole comparator circuit have four parts:the bias current mirror, the front differential amplifier, the middle-class active load differential amplifier circuit and the output stage common source amplifier circuit.Finally, we simulated and analysised the overall circuit, given the system a number of targets of parameters and the system conversion efficiency. The simulation results show that the system has a good linear adjustment capacity and load regulation capability,and with high system conversion efficiency.