Design And Research Of The Power Supply Circuit With High PSRR And Fast Transient Response

Switching power supply is widely used in all kinds of electronic devices because of its small size,light weight,high efficiency,low power consumption and other advantages.And it is moving towards miniaturization,high frequency and digitization.With the development of technology,the function of electronic devices is becoming more and more complex,which requires better performance of switching power supply.The power supply circuit,providing working voltage for the other function modules in switching power supply driving control chip,plays a decisive role in the whole chip function.First,the background and classification of switching power supply are introduced in this paper.Then the background,significance and component of the power supply circuit are analyzed.Several existing literatures of power supply circuit for switching power supply driving control chip are introduced in this paper,based on which,the development trend of power supply circuit for switching power supply driving control chip is summarized as:wide input voltage range,strong power supply noise suppression capability,small area,and fast transient response.Secondly,the structure of power supply circuit in switching power supply driving control chip is presented in this paper.The structure and principle of the bandgap reference circuit and the low dropout linear regulator(LDO)are derived and analyzed in this paper.Aiming at the development tendency of the power supply circuit in switching powersupply driving control chip,a novel power supply circuit with wide input voltage range,high power supply rejection ratio(PSRR)and fast transient response is proposed in this paper.It consists of a voltage-stabilizing circuit with wide input voltage range,a bandgap reference with high PSRR and a LDO with fast transient response and no large capacitance.The proposed voltage-stabilizing circuit with negative feedback structure not only broadens the range of input voltage of the chip but also allows more fluctuation in the input voltage.And the proposed bandgap reference circuit with pre-regulator provides a stable reference voltage for the chip not affected by temperature and has a higher power supply noise rejection performance.As for the proposed LDO,the miller compensation technology with adjusting zero resistance and transient enhancement technique are adopted in this paper,which improve its stability and transient response speed.In addition,these techniques make the LDO work steadily in a wide range of temperature without a big capacitance and achieve a good line regulation and load regulation.Finally,based on 0.18?m BCD technology,Hspice software is used to simulate the proposed power supply circuit.Simulation results show that under the typical process corner the input voltage range of the power supply circuit is 6V?18V,the output voltage is 5 V,the maximum output current is 10mA,the linear regulation and load regulation are less than 0.01%,and the quiescent current is less than 100?A.All indexes meet the design requirements.