Advantages and Disadvantages of Linear Regulated Power Supplies and Switching Power Supplies
Linear regulated power supplies and switching power supplies are two different ways of designing power supplies, each with their own characteristics, and the questioner doesn't point out which aspect of the comparison is being made? Lifetime profile, quality, performance for the load? Ripple factor? Or weight, volume, anti-interference ability, price, etc., because the linear regulated power supply and switching power supply have their own advantages and disadvantages for different indicators of the results are different, the following briefly explains the characteristics of the two power supplies.
1, linear power supply
Linear power supply voltage feedback circuit works in the linear area, the basic principle is first through the transformer will be high-voltage alternating current into a more suitable low-voltage alternating current, and then rectified and filtered into a DC voltage, and finally through the regulator circuit output a stable DC voltage.
Linear power supply in the earlier period has been widely used, now the technology is very mature, its main advantage is high stability, small ripple, power supply ripple coefficient represents the quality of the power supply, now the linear power supply ripple can generally be done below 5mV, the higher-grade linear power supply ripple can be achieved below 0.5mV, and linear power supply internal high-frequency devices, so there is almost no high-frequency interference and high-frequency noise. The disadvantage is that the efficiency is low, the heat generated by the adjustment tube is large, the volume is large, bulky, especially the transformer volume is large, there is also the volume and weight of the filter capacitors are also very large, and can only step-down, not boost.
2, switching power supply
Switching power supply is very common in today's equipment power supply, such as cell phone chargers, notebooks, display adapters, etc., the basic principle of switching power supply is first rectified through the rectifier bridge will be rectified to high-voltage DC, and then through the power supply driver chip, switching tubes and other components of the high-frequency oscillator circuit so that the DC voltage is converted to a high-frequency pulse voltage, converted to an output AC voltage through the high-frequency transformer and then after the rectifier, Filtering to get low voltage DC voltage.
The main advantages of switching power supply for small size, light weight, high conversion efficiency, a wide range of input voltage, anti-interference ability, the same power switching power supply, its weight is only about about 25% of the linear power supply, the conversion efficiency of up to 70% or so, while the linear power supply is only about 30%. Disadvantages: more high-frequency chips in the circuit, working in a high-frequency environment, high-frequency interference and high-frequency noise are larger! Ripple is large, switching power supply ripple is generally in the 50mV ~ 200mV or so, the better quality of the switching power supply ripple can be done within 10mV, but the difficulty and high price! There is also the switching power supply circuit design is complex, high failure rate, maintenance and repair is not convenient.
Summary: It can be seen that the linear power supply and switching power supply have their own advantages and disadvantages, only according to the actual situation of the more focused on which, if the load on the power supply quality requirements are high, such as the requirement of ripple factor is small, high-frequency interference and high-frequency noise, etc., linear power supply dominant in this regard, such as to the audio circuitry system, the power supply of the analog input/output system, etc.; if the volume, weight requirements are high, easy to carry, the requirement of high conversion efficiency, anti-vibration and anti-damping. Requirements for higher conversion efficiency, anti-interference capability, switching power supply dominant. If only from the performance considerations, the choice of linear power supply is better, linear power supply high-frequency interference and noise are very small, ripple is also small, the load damage is small, the service life of the load is longer.
