Power adapter refers to an external power supply used to convert AC grid voltage into a fixed, single-channel low-voltage DC or low-voltage AC output voltage. Its product name can be: power adapter, transformer, switching power supply or power supply, etc.
If the laptop computer launched by Compaq in November 1982 is regarded as the earliest prototype of a laptop computer, then the laptop has been with us for 35 years since its birth. As an important productivity tool that promotes human development, laptops have become around us today. indispensable role. After decades of development, the form, portability, safety, stability, performance and many other aspects are different. However, the power adapter that was born with the notebook seems to rarely attract people's attention. Today, the author will Let’s talk to you about laptop power adapters.
Today's thin and light notebooks have become the most popular notebook category. Of course, on top of thin and light notebooks there are two-in-one notebooks designed for mobility and portability. In the era of mobile Internet, the demand for mobile office has also made notebooks become thinner and lighter. When the size is fixed, the portability of a notebook is usually evaluated into two parts, one is the bare machine weight, and the other is the travel weight ( Bare metal + power adapter weight), often some products maintain a very good bare metal weight, but the power adapter has become a stumbling block. This is more embarrassing. Is there no way to make the notebook power adapter more compact?
In 1985, Toshiba (TOSHIBA T1000) took the lead in externalizing the power supply of notebook computers, creating the world's first independent notebook power adapter, and began the commercialization and popularization of notebook computers. If you look carefully, 32 years have passed. During this period, notebooks have undergone earth-shaking changes. In comparison, changes in power adapters have been much slower. Because the design of the hardware circuit and the size of the components cannot be reduced in a short time, after all, this goes against the basic physical principles. So, what’s the difficulty in shrinking a laptop power adapter?
The power supply required by laptops is stable constant voltage direct current, and the power supply at our homes is usually around 100V-240V (alternating current, AC for short), while the power supply on airplanes and other vehicles is usually around 12V (direct current, DC for short). Generally speaking Unstable power supply cannot directly charge the laptop, otherwise the battery and laptop will be damaged. So we invented the great laptop power adapter. Its working principle is to use the principle of switching power supply to convert unstable power into the constant voltage direct current needed by the laptop through a conversion circuit to power and charge the laptop. But is this the end? Of course not. There must also be overcurrent protection circuits, overvoltage protection circuits, short-circuit protection circuits and other protection circuits to prevent the laptop from burning out.
Let’s just talk about a notebook that needs a 19V 3A DC power supply. Let’s talk about the voltage transformation process. The 220V AC power is first converted into high-voltage DC power through the rectifier circuit, and then converted into high-frequency and high-voltage pulses through the switching tube, and then converted through the transformer. It is a low voltage (such as 19V) pulse. The 19V low-voltage pulse goes through a rectifier and voltage stabilizing circuit and becomes a stable 19V DC... Are you already dizzy...
There is no unified standard, so laptop power adapters have such complicated classifications
At present, the most difficult problem for laptop power adapters is that there is no unified standard, and various power adapters are growing wildly. Therefore, the laptop power supplies we see are all diverse and difficult to classify. According to the purpose, it is divided into AC use (for example, all the AC power used in homes and offices is called AC), and DC use (for example, all the DC power used in cars and airplanes is called DC).
According to the output voltage and current (the label on the back of the charger is usually written behind OUTPUT, how many V and how many A are written), including 12V series, 15V series, 16V series, 18.5V series, 19V series, 19.5V series, 20V series, 24V series, etc. This is just the voltage. The current of the same series can be very different~ In addition, even if the voltage and current are the same, the chance of their interfaces being the same size is very small, just from the shape of the interface , long, flat, square, round, however, circles can also be divided into large circles and small circles... So is this really difficult?
The name of the power adapter can be: power adapter, transformer, switching power supply or power supply, etc.
Power adapter products are increasingly widely used in various electrical products, especially information technology equipment, telecommunications terminal equipment and audio and video equipment, such as laptops, tablets, mobile phones, multimedia players, LCD monitors, etc.
Currently, my country implements a compulsory product certification management system for power adapters for audio and video and information technology equipment. These products must be marked with the CCC compulsory certification mark before they can be sold out of the factory. The power adapter has been included in the national compulsory certification catalog since August 1, 2003.
In recent years, with the continuous expansion of the market for portable electronic products such as mobile phones and tablet computers, the domestic power adapter industry has developed rapidly both in terms of technical level and scale. The design has been gradually improved and the output has been continuously improved. However, the quality of its products is still There is a lot of room for improvement.
At present, the main standards for power adapters in my country are GB4943.1-2011 "Safety of Information Technology Equipment Part 1: General Requirements" and GB8898-2011 "Safety Requirements for Audio, Video and Similar Electronic Equipment". GB 9254-2008 "Radio disturbance limits and measurement methods for information technology equipment", GB 13837-2003 "Radio disturbance characteristics limits and measurement methods for sound and television broadcast receivers and related equipment", etc.
According to relevant standards, the state and relevant quality inspection departments have carried out multiple supervision and spot inspections of power adapter products from 2003 to 2012. The spot inspection products cover power adapters for information technology equipment, power adapters for telecommunications terminal products, and audio and video products. Use the power adapter. The main problems found during the spot inspection are in the aspects of marking and usage instructions, plug type and size, wiring, connection and power supply, electric strength resistance, conduction harassment, radiation harassment, etc.
It is difficult for consumers to distinguish the quality of a power adapter when purchasing it, but they can pay attention to the following points:
(1) Products that have obtained "CCC" certification are preferred. If possible, try to check the authenticity and validity of their certificates on relevant websites.
(2) Check the logo of the power adapter. Qualified products must include information such as rated input voltage or rated voltage range, symbols of power supply properties, safety instructions, etc. Consumers should not purchase power adapter products with full foreign language markings.
(3) Select the power adapter that matches the whole machine. Before purchasing a power adapter, you need to understand basic information such as the electrical parameters of the complete appliance used with it. The output voltage must be consistent with the rated voltage of the complete machine.
(4) Check the plug and interface of the power adapter. A loose interface will make the current received by the whole machine unstable, and may also form a large instantaneous current, causing damage to the whole machine; while an interface that is too tight will make it difficult to plug and unplug or even damage the interface.
