Design Research Of A Linear Voltage-Stabilized Power Supply

Voltage-stabilized power is an essential for a variety of electronic circuits and electronic equipment, its importance of the entire circuit is self-evident. All electrical equipment have specific requirements for power supply, including the output voltage, output current, volume, efficiency, etc. In addition to these basic requirements, with the continuous development of social sciences and industrial technology, the power requirements are increasingly demanding, including the transient response, power line/load regulation, reliability and performance parameters.In practical applications, voltage-stabilized power can be divided into switching power supply, linear power supply and switch-linear composite power according to the work status of the regulator. They each have their own advantages and are widely used in various occasions. The linear regulator power supply have a smalle-ripple noise, stable output and good transient response, etc. In this thesis, we compared their advantages and disadvantages respectively, on the basis of understanding the working principle of linear power supply and switching power supply, determined a program of design a linear power supply. Firstly, this thesis made a theoretical analysis about the main parts of a linear power supply, including the transformer, rectifier and filter circuit and so on, as well as the calculation of important parameters, and constructed the specific circuit with simulation software, designed a high-precision linear regulated power supply, and made a performance simulation test in all aspects, the main parameter characteristics are as follows:1.Output voltage range:0～20V. output current range0～3A. continuously adjustable.2.The circuit has constant voltage and constant current two output modes, and with over-current protection.3. Main parameters through simulation software are:CV mode:load regulation is22mV, line regulation is0mVCC mode:load regulation is1mA. line regulation is15nAThe transient response time is about25us Compared with ordinary linear regulated power supply, the major innovations of this thesis are as follows:1.Designed a constant current drive circuit at the output side, to ensure the stability of the output voltage when the output voltage is small.2.In this design, as the output current has a wide range (OA to3A),therefore, added an additional measures in current detection circuit, to ensure the accuracy of the current measurement and reduce the power consumption.3.Added a output voltage feedback loop to regulate the voltage set point voltage, to avoiding output voltage’s pulse change when switching constant current working mode to constant voltage mode.