Type The Pfm Step-up Dc-dc Converter Circuit

DC-DC converter is one of switching regulators, through which a rating voltage converts to a required voltage. It has the virtues of high integration level, most cost effective, lower component count switcher solution, high performance, forming high efficiency power supply and so on. And it has widely application over the world. For the application background of portable electronic products, which need batteries to offer voltage, the implementation technique of PFM controller in DC-DC converter is also studied in this dissertation and a kind of power controllers for DC-DC converter is designed. The PFM controller of boost DC-DC converter has the advantages of high-precision, simple achieved circuit, low power waste and small IC area. At the same time, the IC has the over voltage and over current protect measures. Cooperating with simple periphery component, a full DC-DC converter is formed.At first, the dissertation analyses the basic theories of voltage regulator and DC-DC converter. The basic theory of pulse frequency modulation (PFM) mode is given. Then the general structure of the IC is designed based on its function requirement. Combined with its work condition, the working course is showed. And each sub-circuit is designed and simulated.We also design the process and layout of the IC. The process is designed by standard CMOS fabrication. At the same, we use the fabrication compatible with CMOS to fabricate bipolar, which can improve performance, reduce the IC area and economize the cost.The simulation of the whole circuit indicates that the IC has achieved our expectation including function and parameter targets. The layout design has accorded with DRC and LVS.The features of the IC are:1.9V to output voltage input supply voltage;3.3V or 5V output voltage; <1% output voltage ripple;>80% efficiency over wide load range;150uA no-load battery current (Vout=3.3V);5uA shutdown mode;Up to 250kHz switching frequencyThe DC-DC converter can be widely used in portable electronic products, which is as supply management IC.