| At present,integrated PWM switching power supply has been widely used in smart home,communication equipment and other fields.In order to meet the performance requirement of power supply such as household intelligent appliances and communication equipment,switching power supply must be developed in the direction of high efficiency,high precision,low power consumption and small size.The chip in this paper is a power management chip based on AC/DC switching power supply converter.The non-isolated buck floating-ground structure is adopted in the peripheral of the chip.The adoption of floating-ground structure in the chip can not only reduce the cost of the whole chip and the volume of PCB,but also greatly reduce the static power consumption of the chip itself.The chip uses unipolar power factor correction and Buck structure as the main control circuit of power factor correction to realize fast adjustment of output voltage and power factor correction.The chip adopts peak current mode and chooses current mode Pulse Width Modulation(PWM),which has high constant current precision.This paper completes all the work of system construction,circuit parameter calculation and circuit design.The sub-circuits and the whole circuit are designde and verified by cadence softerware.And the Whole circuit is built and tested by 0.5um BCD process.The simulation result showed that the chip can work under the full voltage range of 85-265 V AC input,the output Voltage is 18 V,and output current is 300 mA,which meets the design requirements of function parameters.In innovation,the soft startup combined with over-current protection can reduce the overall layout volume and power consumption.In the benchmark circuit,the speed of startup is increased innovatively,and the stability of the benchmark voltage can be achieved at 110 us.Therefore,the chip meets the needs of low-power household appliances applications,and has great advantages in volume,power consumption and cost. |
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