Types and Selection of DC Stable Power Supplies
According to custom, DC stabilized power supply can be divided into chemical power supply, linear stabilized power supply and switching stabilized power supply, which have different types respectively: chemical power supply Dry cell, Lead–acid battery, nickel cadmium, nickel hydrogen and lithium ion batteries we usually use belong to this category, each with its advantages and disadvantages. With the development of science and technology, intelligent batteries have emerged; In terms of rechargeable battery materials, American researchers found that a kind of Iodide of manganese can be used to produce environmentally friendly rechargeable batteries that are cheap, compact, have a long discharge time, and maintain good performance after multiple charges. A common characteristic of linear stable power sources is that their power device adjustment transistor operates in the linear region and stabilizes the output by adjusting the voltage drop between the transistors. Due to the high static loss of the adjustment tube, a large heat sink needs to be installed to dissipate heat. Moreover, due to the transformer operating at the power frequency (50Hz), it is relatively heavy. The advantages of this type of power supply are high stability, small ripple, high reliability, easy to make multi-channel, and continuously adjustable output. The disadvantages are large volume, bulky, and relatively low efficiency. There are many types of stable power sources of this type, which can be divided into stabilized power sources, stabilized current power sources, and stabilized current (bistable) power sources that integrate stabilized voltage and current. The output value can be divided into fixed point output power supply, band switch adjustment type and Potentiometer continuously adjustable type. From the output indication, it can be divided into pointer indication type and digital display type, etc. A type of stable power supply that is different from linear stable power supply is a switch type DC stable power supply. Its circuit types mainly include single end flyback, single end forward, half bridge, push pull, and full bridge. The fundamental difference between it and a linear power supply is that its transformer does not operate at power frequency, but rather operates from tens of kilohertz to several megahertz. The function tube does not operate in the saturation and cut-off zones, i.e. in the on/off state; The switching power supply is named after this. The advantages of switching power supply are small size, light weight, and stability and reliability; The disadvantage is that compared to linear power sources, the ripple is relatively large (generally ≤ 1% VO (P-P), and good ones can achieve more than ten mV (P-P) or less). Its power can range from a few watts to several thousand watts, and there are products available. The price range is from 3 yuan to over 100000 yuan/watt.
