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Differences and relations of switch power supply and linear power supply

Writer:en.turnmax-tech.comSource:TURNMAX Date:2017-05-07
Brief introduction of switching power supply:
Our common power supply includes the power adapter and the charger that all belong to the switching power supply. Switching power supply is a kind of power supply to maintain stable output DC voltage by controlling the time ratio between switching and opening and closing. Switching power supply is composed of pulse width modulation (PWM), IC and MOSFET field effect transistor. The high frequency switching power supply is the direction of its development. High frequency makes switching power supply miniaturized, and makes switching power supply enter a wider application field, especially in the field of high technology, which promotes the miniaturization and portability of high-tech products. In addition, the development and application of switching power supply are of great significance in saving energy, saving resources and protecting the environment.
The principle of switching power supply:
The switching power supply mainly includes input power grid filter, input rectifier filter, inverter, output rectifier filter, control circuit and protection circuit. Below to introduce their functions respectively: input power filter is used to remove from the AC power network such as lamp switch, household appliances switch, air conditioning switch, lightning interference ripple, high frequency noise it will also prevent the switching power supply to the power grid diffusion; input rectifier filter: it is the power input the voltage of the rectifier filter, provide DC voltage converter; inverter: it is a key part of the switching power supply. It is to transform the DC voltage into high frequency AC voltage, and to output and input part of the isolation grid; output rectifier filter: it will be a high frequency AC voltage rectifier converter output DC voltage required, while also preventing noise on the load disturbance; control circuit: detecting the DC output voltage, and the compared with the reference voltage amplification. Modulate the pulse width of the oscillator, so as to control the converter to maintain the stability of output voltage. Protection circuit: when the switching power supply is overvoltage and over current, the protection circuit will stop the switching power supply to protect the load and the power itself. Switching power is a conversion device that rectifies alternating current into DC power.
The advantages of switching power supply are small volume, light weight, convenient portability, high efficiency, strong anti-interference and wide output voltage range. Especially in Europe and America, the switching power supply has highlighted its advantages in terms of power efficiency and standby power consumption.
A brief introduction to linear power supply:
The linear power supply is to reduce the magnitude of the voltage through the transformer first through the transformer, then rectifying it through the internal rectifier circuit, so as to get the pulse DC power, and then get the DC power supply conversion device with tiny ripple voltage after filtering.
Working principle of linear power supply:
Linear power supply is in fact the transformer output end on a large power transistor, the control circuit can control the output as long as the base current of the transistor output a small current to the transistor, the power supply system in Transformer Based on voltage and time, thus stabilizing performance of the linear regulated power supply is better than that of the switch the power transformer or 1-3 orders of magnitude. But the power transistor (also known as the tube) generally takes 10 volts, each 1 amps of output current will consume 10 watts of power within the source, such as 500V 5A in the power loss of the power tube, 50 watts, accounting for 2% of the total output power, and efficiency than linear power transformer slightly lower.
The advantages of linear power supply: stable performance, no interference with high frequency ripple. The disadvantages of linear power supply: heating and low utilization of energy. No power supply is available for selection
The voltage feedback circuit of the linear power source is in the linear (amplification) state, and the voltage of the switching power supply is the voltage regulated pipe working in the saturation and cut-off area, that is, the switching state. Linear power supply is then fed into the output voltage sampling comparing with the reference voltage the voltage amplifier, the output voltage of the amplifier as the input voltage regulator, to control the adjustment of the pipe junction voltage varies with the input changes, so as to adjust the output voltage, but the switch power source is changed by adjusting the opening and closing of the tube the time is to change the duty cycle to change the output voltage. From the point of view: the main characteristics of linear power supply technology is mature, but the production cost is not low, the price has been compared with the switching power supply has lost much advantage, but the linear power supply can achieve stability, high ripple small, interference and noise are smaller than their own, but because the work in power frequency (50Hz) transformer, large volume, low efficiency, the overall volume is larger, more cumbersome. And the input voltage range is high; and high frequency switching power supply is the working condition, the volume of the transformer is relatively small, relatively light, but compared with the linear power supply to output ripple is large, but because of the simple structure, low cost high efficiency (efficiency, switching power supply on the market is up to 90% above) on many occasions has been replaced by the linear power supply, the power supply is the future development trend.
More details of the power supply, please continue to pay attention to the official website of Dongguan tengmao Electronics Co., Ltd. or the scavenging two-dimensional code
Links: Dongguan tengmao Electronic Technology Co. Ltd. the main R & D and production: switching power supply adapter, LED power supply, LED power supply, water supply, power supply equipment, quick charger, QC3.0 charger, TYPE-C charger, car charger charger conversion pins, printer, power board, intelligent socket, apple data line

TypeInfo: Industry News

Keywords for the information:Differences and relations of switch power supply and linear power supply