Based On A Cross Modulation Mode Of Power Management Chip Design

Since the power becomes the necessity of human life, the technology about the power has getting more and more attention, and thus has acquired unprecedented development. The huge demand of consumer electronics market at home and abroad also activates the power management IC industry. The monolithic integrated switching power supply chip with its many advantages including high efficiency, low cost, high accuracy, small size and high reliability takes up a place in the power management chip marketThe main aim of this paper is to design a monolithic integrated switching power supply chip which has pulse skip modulation. It is mainly used in cell phone charger.The chip integrates a MOSFET whose breakdown voltage is up to700V.It achieves PSM by using voltage feedback, current feedback technology. It has the following characteristics: direct ON/OFF control; frequency shuffling and adjustable gate drive greatly improving EMI; VDD under voltage lockout with hysteresis(UVLO) and etc.The thesis mainly discusss the following circuit:state-machine, current-limit comparation,logic circuit and over-thermal module. The current-limit comparation and state-machine together achieve the aim of current limit adust of MOSFET; the logic circuit achieves the on/off of MOSFET; the osc circuit generates the clock of the whole IC; the over-thermal circuit protect the IC from high temperature. The paper analysis these circuits in detail, and I use spectre to simulate these circuits, giving the waveform to verify the correction of the circuits. The simulation of the modules all achive the requirment. In the end, the article introduces the layout design process. The layout of the chip are designed.