Why do desktop computer power supplies use switching power supplies instead of transformers like amplifiers?
The reason why desktop computer power supplies don't use the kind of transformers used for amplifiers is because they are bulky, inefficient and costly.
A computer is a device with high power supply requirements. It's not just a requirement for a clean and smooth output current, but also a complex and varied set of voltage and current requirements. There are ± 12v, 5v, 3.3v, etc., in particular, there are 5V and 3.3V current up to dozens of amperes, which requires multiple secondary coils of the transformer should be a very thick line, rectified but also separately for voltage regulation. In order to ensure that the output voltage stability of each voltage regulator circuit itself to have a certain pressure difference, such as 5V all the way to the rectified voltage of at least 8V, if the current of 20A will have to be 60W of power consumption to the regulator device, which is only all the way to the loss of the entire power supply losses together, at least one hundred watts of electricity to be wasted, and this into the heat of the power, the computer will be turned into a small furnace.
Speaking of which, some people may ask, now there are so many high-efficiency DC a DC module why not use it? Please do not forget that all high-efficiency DC conversion module are
Is a switching power supply, switching power supply from this link, in front of the large transformer has no meaning.
If you use switching power supply above these problems can be solved. First of all, due to the circuit frequency of tens of kilohertz, the transformer volume can be made very small, greatly reducing the size and weight of the power supply. The volume and weight of the power supply. In addition, there is no need to regulate each way individually, as long as you find a way as a reference can be. For example, select a 5V group to extract the voltage information directly back to the transformer primary power supply. Feedback to the transformer primary power supply switching tube, by changing the duty cycle to achieve a constant voltage of the group, so that the other groups of voltage stabilisation.
Another advantage of this mode is that the input voltage range is wide, up to 160~240V, which is impossible for power supply modes using bulky core transformers. impossible for power supply modes that use bulky core transformers.
