| The fast development of handy-terminals drives the growth of DC/DC converters. Small, low power, high efficiency produces are more and more popular. At first, this thesis will introduce the DC/DC converter's classify, elements and typical structure. And then, based on a program (a small, high efficiency PWM DC/DC converter) make farther analysis.The first chapter of this thesis is an introduction of DC/DC converter. Chapter two class the DC/DC and explain the elements. Chapter three shows the details of PWM mode—the most popular mode. Chapter four comes to the project of a small, high efficiency PWM DC/DC converter. Chapter five is the simulation of the project. Chapter six is the layout of the project. Chapter seven refers to the integrate resistors and capacitors. Chapter eight is the summarize.The emphasis of this thesis is the design of a DC/DC converter. This converter is a low-noise, pulse-width-modulated (PWM), DC-DC step-down converter. It powers logic and transmitters in small wireless systems such as cell phones, communicating PDAs, and handy-terminals. The device features an internal synchronous rectifier for high efficiency; it requires no external Schottky diode. Excellent noise characteristics and fixed-frequency operation provide easy post-filtering. It is ideally suited for +3V or +5V fixed input applications.The device operates in one of four modes. Forced PWM mode operates at a fixed frequency regardless of the load. Synchronizable PWM mode allows an external switching frequency to control and minimize harmonics. Idle Mode (PWM/PFM) extends battery life by switching to a PFM mode during light loads. Shutdown mode places the device in standby, reducing quiescent supply current to under 0.1μA. |
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