advantage

1) Low power consumption and_high efficiency. In the switching regulator power supply circuit of FIG. 1, the transistor V is alternately operated in the on-off and_off-on switching states under the excitation of the excitation signal, and_the conversion speed is fast, and_the frequency is generally about 50 kHz. In some technologically advanced countries, hundreds or nearly 1000 kHz can be achieved. This makes the power consumption of the switching transistor V small, and_the efficiency of the power supply can be greatly improved, and_the efficiency can reach 80%.

2) Small size and_light weight. From the block diagram of the switching regulator power supply, it can be clearly seen that the bulky power frequency transformer is not used here. Since the dissipation power on the adjustment tube V is greatly reduced, a large heat sink is omitted. Due to these two reasons, the switching regulator power supply is small in size and_light in weight.

3) Wide voltage regulation range. The output voltage of the regulated power supply is regulated by the duty cycle of the excitation signal. The change of the input signal voltage can be compensated by frequency modulation or widening. Thus, when the voltage of the power frequency grid changes greatly, it can still Guaranteed a stable output voltage. Therefore, the switching power supply has a wide voltage regulation range and_the voltage regulation effect is very good. In addition, methods for changing the duty ratio include pulse width modulation type and_frequency modulation type. In this way, the switching regulator power supply not only has the advantage of wide voltage regulation range, but also has many methods for realizing voltage regulation. The designer can flexibly select_various types of switching power supply according to the requirements of practical applications.

4) The efficiency of filtering is greatly improved, so that the capacity and_volume of the filter capacitor are greatly reduced. The operating frequency of the switching regulator power supply is basically operating at 50 kHz, which is 1000 times that of the linear regulated power supply , which makes the filtering efficiency after rectification almost 1000 times. It is half-wave rectified and_then capacitively filtered, and_the efficiency is also increased by 500b. Under the same ripple output voltage, when the switching regulator power supply is used, the capacity of the filter capacitor is only 1/500-1/1000 of the filter capacitor in the linear regulated power supply.

5) The circuit form is flexible and_diverse. For example, there are self-excited and_other-excited, wide-tuned and_frequency-modulated, single-ended and_double-ended, etc. Designers can use the characteristics of various types of circuits to design switches that can meet different applications. Power Supply.

Disadvantage

The disadvantage of switching regulators is that there are more serious switching disturbances. In the switching regulator power supply, the power adjustment switching transistor V operates in a switching state, and_the generated AC voltage and_current generate peak interference and_resonance interference through other components in the circuit. If these interferences are not taken to suppress, eliminate, and_Shielding will seriously affect the normal operation of the whole machine. In addition, since the switching regulator power supply oscillator is not isolated by the power frequency transformer, these interferences will be stringed into the power frequency grid, causing serious interference to other nearby electronic instruments, equipment and_household appliances.

At present, due to the gap between domestic microelectronic technology, production technology of resistive container parts and_magnetic material technology and_some advanced technology countries, the cost cannot be further reduced, and_the reliability is further improved. Therefore, in Chinas electronic instruments and_mechatronics instruments, switching power supplies have not been widely used and_used. Especially for high-voltage electrolytic capacitors, high-pressure high-power switch tubes, magnetic core materials for switching transformers, etc., which are not in the power frequency transformer switching power supply, they are still in the research and_development stage in China. In some advanced countries, although the switching power supply has a certain development, there are still some problems in practical applications, which can not be very satisfactory. This exposes another disadvantage of the switching regulator power supply, that is, the circuit structure is complicated, the failure rate is high, and_the maintenance is troublesome. In this regard, if designers and_manufacturers do not pay full attention to it, it will directly affect the promotion and_application of switching power supply. Today, the main reason for the difficulty in popularizing and_applying switching power supplies is that it is difficult to manufacture, has troublesome maintenance, and_has high cost. [2]