Research On AC-DC Power Control Chip With High Precision And Low Cost

With the continuous improvement of the quality of life,diversified functional is no longer the only criterion for people to use intelligent devices.People begin to have more requirements for the appearance of the equipment they want to buy.The equipments with low power and low voltage have rich functions and small size,which is in line with people’s consumption concept and has great market potential.The power is the core and basic part of low-power equipment.Although many mature designs have been designed in the market,there is still a lot of room for improvement in low-voltage and low-power applications.The main work of this thesis is to design a control scheme suitable for low-voltage and low-power equipment,which has high efficiency,high precision,safety and simple application.The output power of low-power equipment power is usually the same order of magnitude as the power loss,which has a great impact on efficiency.Aiming at the phenomenon of low efficiency of the power,this thesis analyzes the power loss of the selected topology and models the loss.Then,the peak current and control frequency curves with higher efficiency are planned according to the loss model.The test results show that the average efficiency is 55.56% when the input voltage is 230 Vac,the output voltage is 3.3Vdc and the high-efficiency control curve is used,which is 6.56% higher than the level 6 energy requirement issued by Department of Energy(Do E6).The equipment with low voltage and low power usually expensive and have an operating voltage below 5V,which requires high output accuracy and high safety of the power.In order to eliminate the introduced error at the negative input end of the error amplifier,a frequency compensation control framework is designed in this thesis,which greatly improves the output control accuracy while adopting high-efficiency control curve.In order to solve the safety problem caused by overcharge,a control structure is added to the compensation control scheme,and the overcharge voltage is reduced by forcibly controlling the compensation voltage.The scheme described in this thesis is implemented with0.18μm/60V-HVCMOS of Central Semiconductor Manufacturing Corporation(CSMC)and occupies a die size of 0.7×0.86 mm2.The test results show that the output accuracy is 0.9%,0.9% and 1.3% at 3.3V,5V and 12 V,respectively.Compared with the existing single-stage resolutions,lower output voltage and higher output precision are achieved.In order to obtain high-precision voltage,the traditional equipment with low-voltage and low-power usually adopt multi-stage structure.Multi-stage has many peripheral devices,resulting in high volume and cost and more difficult to reduce.The single-stage power described in this thesis is designed with BUCK topology with simple peripheral structure,and a die,the power switching and high-voltage deletion transistor are packaged in a multi-chip package to achieve high integration and simple peripheral structure.