ADD：DC-stable power supply types and basic knowledge
DC-stable power supply type and use:
DC-stable power supply can be divided into chemical power by habit, linear stability and stable power supply and switching power supply, they also took a variety of different types:
Chemical Supply
We normally used batteries, lead acid batteries, nickel cadmium, nickel hydrogen, lithium-ion battery are of this kind, have their own advantages and disadvantages. With the scientific and technological development, but also produce intelligent battery; in rechargeable battery materials, the U.S. developed a manganese iodide were found, it can be used to create cheap, small, discharge time, still maintained in many charged good environment-friendly rechargeable battery.
Linear stability of power
Linear stability of power supply is a common feature to adjust its power devices operating in the linear area, by adjusting the voltage drop between the tube to stabilize the output. As the great loss to adjust the static tube, need to install a large heat sink to cool it. And because the transformer in the frequency (50Hz) on, so a larger weight.
Advantages of such power, high stability, ripple, high reliability, easy to made multiple output continuously adjustable finished. Disadvantage is that bulky, relatively heavy, relatively low efficiency. Such stable power supply there are many, from the output of the power supply and can be divided into steady power supply and set voltage regulator, the regulator steady flow in a steady flow (bistable) power. The output value from the perspective can be divided into fixed-point output power, wavelength switches and potentiometers continuously adjustable adjustable few. Instruction pointer from the output can be divided into direct and digital display-type type type and so on.
Switching DC Power Supply
Linear regulated power supply with a different class of stable power supply is a switching DC power supply, its main single-circuit type of flyback, single ended forward, half bridge, push-pull and full bridge. It is the fundamental difference and linear power transformer is that it does not work but work in the frequency several kHz to several megabytes in Hz. Function control is not working in the saturated and cutoff switch state; switching power supply hence the name.
Switching power supply has the advantage of small size, light weight, stable and reliable; disadvantage relative to the linear power supply ripple is large (typically ≤ 1% VO (PP), good can be more than a dozen mV (PP) or smaller ). It can be from a few watts of power - are products of several kilowatts. Price is 3 yuan - more than ten million / W, the following description of general customary classification of several switching power supply:
1 AC / DC power supply
Also known as a power source of such power, it made since the energy grid through high voltage rectifier to get a DC high voltage for the DC / DC converter in the output ports of one or several stable DC voltage, power from a few watts - a few kilowatts are have products for different occasions. Model specifications of such products are numerous, according to user needs of the communication power of a power supply (AC220 input, DC48V or 24V output) also fall in this category.
2 DC / DC power supply
In the communication system, also known as secondary power supply, it is a power supply or DC battery pack to provide a DC input voltage, by the DC / DC transformation after the output DC voltage by one or a few.
3 Communications Power
Communication is essentially the power of its DC / DC converter power supply, but it is generally to DC-48V or-24V power supply and DC power supply with battery backup for the backup, will be transformed into the DC supply voltage circuit voltage, general it points the central power supply, power supply three kinds of hierarchical power and veneer, the latter the highest reliability.
4 Radio Power
Radio power input AC220V/110V, output DC13.8V, power from the power supply units may be several hundreds of security are security products. To prevent the impact of AC grid power stations, while the need for battery as a backup, so In addition to the output of such a 13.8V DC power supply voltage, but also to charge the battery with automatic conversion.
5 Module Power Supply
With the rapid development of science and technology, on the power supply reliability, capacity / volume requirements are high, the module power supply has increasingly shown its advantages, its high frequency, small size, high reliability, ease of installation and combination of expansion, So more and more widely used. At present, although the current domestic production of the corresponding module, but failed to catch up with international standards of production technology, high failure rate.
DC / DC module power supplies present, although the higher costs, but the application of the long product cycle, the overall cost point of view, particularly because of system failure caused by high maintenance costs and goodwill loss of view, or a cost-effective use of the power supply module cost-effective, this is also worth mentioning that Roche converter circuit, it highlights the advantage of simple circuit structure, high efficiency and output voltage and current ripple Zhi close to zero.
6 special power supply
High voltage low current power supply, high current power supply, 400Hz input AC / DC power supplies, etc., can be attributed to such, can be selected according to specific needs. Switching power supply is generally the price of 2-8 yuan / watt power supply special low-power and high power prices higher, up to 11-13 dollars / watt.
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