Overview of Filter Circuits for DC Regulated Power Supplies
(1) DC stabilized power supply generally consists of four parts: transformer, rectifier circuit, filter circuit, and stabilized circuit.
(2) Rectification utilizes the unidirectional conductivity of diodes to convert alternating current into pulsating direct current. According to the output waveform, rectification can be divided into half wave and full wave rectification. Half wave rectification only requires one diode, but the output is only half of a sine wave, resulting in low conversion efficiency. The output of bridge full wave rectification is a two and a half cycle waveform, which doubles the output voltage, but the number of rectifying diodes increases to four, making the circuit more complex.
(3) The filtering circuit can filter out the AC component in the rectified output and obtain a relatively smooth DC current. The average output voltage increases after adding capacitor filtering. Capacitive filtering is suitable for use in situations where the load resistance is high and the load current is low. When capacitive filtering cannot meet the requirements, filtering can be added to form a compound filtering.
(4) The voltage regulator circuit can automatically adjust the output voltage through the regulator device when the grid voltage fluctuates or the load changes, making the output voltage basically stable. The transistor series voltage regulator circuit is composed of sampling, reference voltage, comparative amplification, and adjustment parts. It has good voltage regulation characteristics and is currently a commonly used circuit. Integrated voltage regulator circuits are becoming increasingly widely used due to their advantages such as small size, light weight, and easy installation and debugging.
(5) The integrated voltage regulator only has three output terminals: input terminal, output terminal, and common terminal, which is easy to use and has good voltage stability.
