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What is the power adapter? What are the functions of the power adapter?
time2006/08/24
- The power adapter can be generally divided into a wall-mounted type and a desktop type. It is a power supply conversion device, generally consisting of a casing, a power transformer and a rectifier circuit, and can be classified into an AC output type and a DC output type according to the output type thereof. Widely used in liquid crystal displays...
Introduction to the power adapter
The power adapter can be generally divided into a wall-mounted type and a desktop type. It is a power supply conversion device, generally consisting of a casing, a power transformer and a rectifier circuit, and can be classified into an AC output type and a DC output type according to the output type thereof. Widely used in liquid crystal displays, monitoring systems, electronic refrigerators, small appliances and other equipment.
The role of the power adapter
The power adapter acts as a transformer and rectifier. The household AC is 220v, and our computer land is DC 12v (as if it is), so we can be sure that the power adapter is a transformer and rectifier. Then the adapter is a transformer, we should all know that the AC 220V is transformed by the transformer, and the DC is changed by the rectifier. Here, there is consumption, and these consumptions are converted into heat, so it is normal for the power adapter to heat up. The transformer is made of silicon steel sheet. After the transformer is energized, the magnetic flux is generated. The magnetic flux will cause a force between the silicon steel sheets to generate a click sound, which is normal. However, the sound of the earth is not normal, and there are many reasons: 1. The AC voltage is unstable. 2. The chip is damaged. 3. Short circuit between turns. 4. Component damage.
Power adapter characteristics
Power converter (AC to DC), converted from AC to DC, and then through the computer, it can not protect the computer, but the computer has a storage device (also called charger), so it can be protected in the event of power failure computer. Both the switching power supply and the adapter are switching power supplies, which are composed of a high frequency switching tube and its control circuit. The adapter power supply is a regulated switching power supply. The switching power supply charger has a floating charging function. The voltage becomes larger as the current becomes smaller. In the end, there is only voltage and no current.
Power adapter label
Most notebook power adapters are suitable for 100 to 240V AC (50/60Hz). Basically, most laptops have external power supplies and are connected to the main unit with a power cord. This reduces the size and weight of the mainframe. Only a very small number of models have built-in power in the mainframe.
There is a nameplate on the power adapter, which indicates the power, input and output voltage and current quantity, etc., pay special attention to the range of input voltage. This is the so-called "travel power adapter", if the country has a voltage of only 110V. This feature is very useful, some parallel laptops are only sold in the country of origin, without this compatible voltage design, even a single input voltage of 110V, will be burned when plugged in China's 220V mains voltage.
Type of power adapter
The power adapter is mainly divided into two types, a switching power supply and a linear power supply.
1. Switching power supply is a kind of power supply that uses modern electronic technology to control the ratio of time when the switch tube is turned on and off, and maintains a stable output voltage. The switching power supply of the power adapter is generally composed of a pulse width modulation (PWM) control IC and a MOSFET.
Advantages: high efficiency, small size, can work in a wide voltage range.
Disadvantages: The interference to the power supply circuit is large, and it is difficult to overhaul when the fault occurs.
2. The linear power supply converts the alternating current through the transformer, and the rectifier circuit rectifies and filters to obtain the unsteady DC voltage. To achieve the high-precision DC voltage, the power adapter must adjust the output voltage through the voltage feedback circuit.
Advantages: This power supply technology is mature, the circuit is simple, and there is no interference and noise from the switching power supply.
Disadvantages: The voltage feedback circuit works in a linear state, the power consumption of the adjustment tube is large, the conversion efficiency is low, and the device is heavy due to the use of an inductive transformer.
Power adapter application
It is widely used in consumer electronics, and the output power is mostly within 100 watts. The market demand is growing rapidly. Applications such as electric bicycle battery chargers, small size LCD TVs, laptops, printers, DVD players and set-top boxes are available. Most of the early power adapters used linear transformers. As consumer electronics products have high efficiency, wide input voltage range, and increased copper, iron and labor costs, the original linear transformers in these power adapters are gradually increasing. Replaced by switching power supply.