Design Of An AC-DC Chip With The PSM Control Mode

Based on the project “Design technique research of power analog intergratedcircuit” of Key Lab of High-Speed Circuit Design and EMC, Ministry of Education inXidian University, the paper focus on the design of AC-DC chip. Through systematicdesign, circuit design, layout design and performance simulation, a AC-DC converterchip with the PSM control mode, named XD1162, is introduced in this paper.A700V high voltage switching power MOS,voltage pre-regulator,bandgap,oscillator,leading edge blanking circuit are integrated in the chip.The protection circuitof current limit,short protection,over voltage protection,auto-restart are also included inthe chip,after the consideration of the chip’s safety. The chip works in pulse skip mode.In these periods, parts of the chip are shut down to decrease the quiescent current forthe consideration of the efficiency.The technique of self-biased supply is used forsaving transformer auxiliary winding. The oscillator can introduce a small amount offrequency jitter,which will reduce the EMI effctively.Based on0.5μm20V BCD process, circuit design and simulation, layout designare accomplished by using the EDA tools of Cadence.85～265VAC input,2.8Woutput power and layout area1560μm×1620μm, the chip has been taped out.