The power adapter regulates the voltage by controlling the on and off time of the adjusting tube. Widely used in a variety of electronic equipment. Today, YHY Power will introduce the basic composition, classification and working principle of the power adapter for you, so that you have a preliminary understanding of the power adapter! Take a look!
Electronic devices cannot be separated from power adapters. The power adapter supplies the power needed by electronic devices. The performance and quality of the power adapter directly affect the safe and reliable operation of electronic equipment, so the demand for the performance and quality of the power adapter of electronic equipment is increasingly high. The existing power adapters mainly fall into two categories: series linear regulated power adapter (abbreviated as linear power adapter) and switching regulated power adapter (abbreviated as power adapter). These two types of power adapters have their own characteristics and are widely used.
Structure and characteristics of linear power adapter
The linear power adapter is usually provided by the power grid alternating current, through the transformer, rectifier, filtering and voltage regulation links to get. The functions of each part of the circuit are as follows:
(1) Power adapter transformer -- the 220V grid voltage is converted into the AC voltage value required by the rectifier circuit, and a small part of the circuit uses capacitor step-down, such as remote control electric fan circuit.
② Rectifier circuit -- convert AC voltage to pulsating DC voltage. The commonly used rectifier circuits are half wave rectifier circuit, full wave rectifier circuit and bridge rectifier circuit.
③ Filter circuit -- the pulsating DC voltage into a smoother DC voltage. The filter circuits commonly used in linear power adapters include inductance filter, capacitance filter and resistance capacitance filter, among which capacitance filter is the most commonly used.
Voltage regulator circuit - the output voltage of the DC power supply adapter is stable, basically not affected by the grid voltage or load. In the linear power adapter commonly used voltage regulator circuit diode voltage regulator, series voltage regulator. Among them, the series voltage regulator has a ready-made integrated circuit, such as fixed voltage output integrated circuit LM78××, LM79××, and adjustable voltage output integrated circuit LM317 and LM337.
Linear regulated power adapter with 4 function modules
The advantages of linear power supply adapter are good stability, fast transient response, high reliability, high output voltage accuracy and low output ripple voltage. Disadvantages are low working frequency, the use of power frequency transformer, filter volume and weight are larger. The adjustment tube works in linear state, with high power consumption and low efficiency, so it needs to install a radiator.
