The switching frequency of switching power supply

The switching frequency is said that the inverter output voltage is actually a series of pulses, pulse width and spacing are not equal. The value depends on the intersection of the wave and the carrier. The higher the switching frequency, the more the number of pulses in a cycle, the smoother the current waveform is better, but the more interference to other devices.
Nonlinear power supply, switching power supply frequency is generally greater than 20KHZ, because to avoid the sound frequency 20KHZ, the market common frequency in 50KHZ–150KHZ, generally in the 60KHZ–90KHZ, more than the 100KHZ frequency of the power supply of the switch tube requirements to be high, the cost is high, so the general will be controlled within 100KHZ
Nonlinear power supply, switching power supply frequency is generally greater than 20KHZ, because to avoid the sound frequency 20KHZ, the market common frequency in 50KHZ–150KHZ, generally in the 60KHZ–90KHZ, more than the 100KHZ frequency of the power supply of the switch tube requirements to be high, the cost is high, so the general will be controlled within 100KHZ

Generation mechanism and Countermeasures of switching power supply EMC

Classification and standard of EMC:
EMC (Compatibility Electromagnetic) is an electromagnetic compatibility, which includes EMI (electromagnetic disturbance) and EMS (electromagnetic anti harassment). EMC is defined as the ability of a device or system to work properly in its electromagnetic environment and not to constitute an electromagnetic disturbance that is not capable of any device in the environment. EMC the entire call is electromagnetic compatibility. EMP is an electromagnetic pulse.
EMC = EMI + EMI EMS: electromagnetic interference EMS: electromagnetic compatibility (immunity)
EMI can be divided into two parts, which are Conduction and Radiation. The Conduction specification can be divided into: Part 15J Class B CISPR; FCC 22 (EN61000-3-2, EN61000-3-3, EN55022) B Class; IT (GB17625, GB13837) and AV (GB17625, GB9254). FCC test frequency in 450K-30MHz, CISPR 22 test frequency in 150K–30MHz, Conduction can use the spectrum analyzer test, Radiation will have to go to a special laboratory testing.
EN55022 is Test Conduction & Test Radiation (conduction & radiation testing); EN61000-3-2 is Test Harmonic (power supply harmonic test); EN61000-3-3 is Test Flicker (voltage fluctuation test).
CISPR22 (Special des Purturbations Radioelectrique Comite) is applied to the information technology. It is suitable for European and Asian regions; EN55022 is the European standard, Part FCC 15 (Communications Commission Federal) is applied to the United States, EN30220 European EMI testing standards, power radiation testing standards are EN55013 frequency in 30MHZ-300MHz.
EN55011 radiation testing standards are: some of the high frequency requirements, some of the low frequency requirements. Conduction (150KHZ-30MHZ) to the LISN mainly is the differential current mode and the common mode impedance for a 100 ohm (50 + 50); LISN is mainly the common mode current and the total circuit impedance for 25 ohms (50 / 50).
4 line 60dB/uV 150KHZ-2MHZ start 9KHZ AV
5 line 100dB/uV 150KHZ-3MHZ PEAK
6 line 100dB/uV 2MHZ-30MHZ PEAK
7 line 70dB/uV 150KHZ-500KHZ QP
Radiated (30MHZ-1GHZ): 4N7/250V Y CAP 90dB/uV 30MHZ-300MHZ ADD
EMI is an electromagnetic interference, EMI is a part of the EMC, EMI (Magnetic Interference Electronic) electromagnetic interference, EMI including conduction, radiation, current harmonics, voltage flicker, etc.. The electromagnetic interference is caused by the interference source, coupling path and the receiver is composed of three parts of the three elements, usually called interference. EMI linear proportional to the current, the current loop area and the square of the frequency: K*I*S*F2 = EMI. I is a current, S is the circuit area, F is the frequency, K is a constant with the circuit board material and other factors.
EMI refers to the external electromagnetic interference. Generally divided into two levels of A Class & B Class. A Class for industrial grade, B Class for the civilian level. Civil to be more stringent than the industry, because of the industrial use of the allowable radiation a little big. Requirements products also products in the EMI test radiation test, in 30-230MHz class B radiation value cannot be more than 40dbm and class a request can not be more than 50dbm (to three meters anechoic chamber, for example) relative to loose the limits, generally class A is that the EMI test conditions under, without intervention from the operator, equipment can according to expected to continue normal work, not allowed to appear below specified levels of performance performance degradation or loss of functionality.
EMI is a normal operation of the equipment to measure its radiation and conduction. At the time of testing, EMI’s radiation and conduction in the receiver has two caps, representing the A Class and B Class, if the observed waveform is more than B line but below the A line, then the product is a class A. EMS is used to test equipment for product interference, observe whether the product can work normally, if the normal work or does not appear to exceed the performance of the standard, for a class. Can automatically restart and restart does not exceed the performance of the standard provisions of the decline in performance for the B class. No need to restart automatically restart C, hang D. The national standard of D level, EN only A, C, B. EMI at work frequency of the odd number is the most difficult.
EMS (Suseeptibilkr Electmmagnetic) is commonly known as the electromagnetic sensitivity of electromagnetic immunity, is the ability to resist external disturbance of the device, EMI is the device’s external harassment.
EMS levels are: A Class, the test is completed after the device is still in normal work; B Class, the test is completed or the test needs to be restarted after the normal work; C Class, the need for human adjustment can be normal to restart and normal work; D Class, the device has been damaged, no matter how the adjustment can not be started. Strictly EMI is B>A, EMS is A>B>C>D.

The design of switching power supply transformer

Switching power supply transformer is the power transformer, which is added to the switch management. In the use, not only has the function of the ordinary transformer’s voltage transformation, but also has the function of the insulation isolation and power transmission. In the switching power supply and other occasions involving the use of high frequency circuit is widely used. Switching power supply transformer design is very important to the use of the switching power supply, suitable design can make the switch power supply transformer better to control the current, the design method is not reasonable to the use of switching power supply transformer
The main materials of the switching power supply transformer are: insulation materials, wire materials, magnetic materials. Switch power transformer with the switch tube together constitute the self-excited or his excited intermittent oscillator, the DC voltage modulated into a high frequency pulse voltage and finally to energy transfer and conversion. When the switch is switched on, the transformer converts the electric energy into a magnetic field to store it, and when the switch is cut off, it is released. In the forward circuit, when the switch is turned on, the input voltage is supplied directly to the load and the energy stored in the energy storage inductor. When the switch is cut off, the energy transfer is carried out by the energy storage inductor. More simply, the role of the switching power supply transformer is to convert the input DC voltage into the low pressure needed in our use.
In the design of the structure of the switching power supply transformer, we should consider the following points, leakage magnetic must be small so that the leakage inductance of the winding can be reduced. In the structure design to make it easy to winding and lead the way so that the transformer is not only simple and convenient, but also for the maintenance and production of the transformer is very helpful. In the design of a reasonable plan, so that the voltage can have sufficient space and function for cooling. If the design of switching power supply transformer on the full consideration of the above factors, then this design can make the switch power transformer more secure, more durable life.
In the design of switching mode power supply transformer when the material choice is very important, and in the choice of core is switch in power transformer, according to the choice of switching power supply transformer use different materials are also different. For use in the us the most extensive core is iron, manganese, and zinc oxide core used in the power supply input filter is used to high permeability core. Because of the low price of soft ferrite, good adaptation and high frequency performance, it is widely used today.
Switching power supply transformer design has certain requirements, these requirements can make it achieve the best use effect. The first is that the leakage inductance is small, because the voltage spike of the switch is connected with the size of the voltage spike, the circuit condition, the collector circuit configuration and the leakage inductance. Secondly to avoid transient saturation, in instantaneous electrical transformer core serious saturation will produce great surge current, in a very short period of time may cause the switch tube damage, generally in actual use will install soft start circuit to solve the problem. The effect of temperature is also considered in the design.
The detection method is very important in the use of the switching power supply transformer. In the detection, it can be seen whether there is an abnormal phenomenon, and the insulation of the switch power transformer is tested by the test. The above is a small series of switching power supply transformer is a brief introduction, we want to help group.

The difference between isolated and non-isolated

There are several trends are driving the development of LED lighting market. First of all is the high brightness LED efficiency of continuous improvement and very high reliability and high reliability of constant current LED driver power supply continues to emerge, followed by the global legislation to ban incandescent lighting (due to its low efficiency) and CFL energy-saving lamps gradually fade out (if broken, it will flow out of the environment harmful mercury). These factors are combined to make LED lighting become a long-term development trend. Of course, low system cost (including LED, thermal management system and LED driver) will always be the driving force for the wide use of LED general lighting. In fact, in many LED lighting products, failure is a common phenomenon, most of which is because of the failure of the power, rather than the failure of LED. At the design level, this means that the OEM must become a hot design expert. LED provide high efficiency, but they are also more heat than incandescent or energy-saving lamps. Because many LED lighting applications are enclosed in a very small space, it is difficult to use ventilation to heat dissipation. If there is no careful thermal design, the LED and the power drive circuit is easy because of high temperature and degradation or permanent failure.
As a product that allows the end user to be safe, it must consider the reliability of insulation and isolation. As a complete product, the surface of the product can be exposed to the part of the user must be isolated, can not let people get electric shock. And from the whole system, the isolation is inevitable, the difference is only set the location of the isolation. Some designers use isolated transformer design, so they can simplify the design of cooling and lamp shades. If you use non isolated driver design, the lights on the shell structure of the insulation requirements must be considered reliable. As a result of power supply, the isolation and non isolation schemes are all the same. The main challenge for the Chinese LED drivers is to find a low cost AC/DC driver, which can meet the performance of more stringent power factor and efficiency in low cost power supply system. In the future, the use of high quality, high reliability power supply will be no longer free of charge in the space constrained and there is a cooling system (such as LED lamps). However, in the end users have used a lot of life in 10000 hours or so…
LED driver power isolation and non isolation 7-5 is currently in the general LED lighting market, there is a non isolated design and isolated power supply. Non isolation design is limited to a dual insulation product, such as a light bulb replacement product, where the LED and the entire product are integrated and sealed in a non conductive plastic, so the end user does not have any risk of electric shock. The two level products are isolated, the price is relatively expensive, but in the user can be exposed to the LED and the output connection (usually in the case of LED lighting and street lighting applications), this product is essential. LED driver power supply with isolation transformers or electrical isolation means that the LED can be directly touched by hand without electric shock. Without the isolation transformer LED drive power still can with protective casing, so as to realize the mechanical part of the insulation, but this time the LED at work and not direct contact. Insulation type light bulb in the future will become the mainstream. Physical design determines that the drive is an isolated or a non – isolated. Safety rules usually require the use of two separate isolation layers. The designer can choose two kinds of physical isolation layer, or plastic mask and glass cover, and use of non isolated power supply. If the cost of physical isolation is too high, there is a mechanical difficulty or absorb too much light, it is necessary to solve the problem of electrical isolation in power. Isolated power supply is usually more than the same power level of non isolated power supply. Lighting designers must be in the design of each product in a lot of cost and design optimization work. Because it is suitable for different applications, it is a protective shield that is used in isolation. In general, they will be analyzed in many ways, such as cost and manufacturing process, efficiency and volume, reliability and safety requirements, and so on. With the high cost of the transformer, but also to make the LED lamps become more practical, to meet the needs of the end user to meet the needs of LED. When the incandescent lamp glass shell is easy to damage, a E27 type of ordinary light bulb can be replaced with LED lights. In addition, in the industrial area or office equipment in the application of the lamps do not need to contact the end user, such as street lamps and shopping malls lighting, then the LED lights do need to isolate the transformer.

Two breakdown phenomenon and protective measures of power transistor in switching power supply

Two about 1 breakdown and protection
Two reasons for the 1.1 breakdown
The two time breakdown is mainly due to the high local temperature caused by the device. The reason for the increase in temperature is that the thermal imbalance is caused by the forward bias, and the reverse bias is caused by the avalanche breakdown.
Because of the thermal resistance of the transistor in the pipe internal distribution is uneven, in some weak areas, the temperature rise will be higher than other parts, forming the so-called hot, local temperature caused by the local current increases, the current increases, so that the temperature rise, so the cycle until a critical temperature, resulting in the breakdown of the tube.
The two breakdown caused by avalanche breakdown is due to the occurrence of an avalanche breakdown, at some point due to the current density is too large, the change of the electric field distribution, resulting in negative resistance effect, so that the local temperature is too high a phenomenon.
1.2 measures to avoid the two breakdown
Opening and closing loss are important factors to affect the normal operation of switching devices. Especially in the dynamic process of the transistor is easy to produce two breakdown phenomenon, this phenomenon is directly related to the switch loss, so it is necessary to reduce the switching loss of the device is the proper use of the device. To reduce the loss can be achieved through two ways to achieve:
(1) to low collector emitter voltage to turn off transistor (Vce);
(2) in the process of the rising of the emitter voltage, the transistor must be reduced to minimize the emitter current. The introduction of the buffer circuit is one of the ways to achieve the above purpose.
1.3 buffer circuit in switching power supply
In the design of the switching power supply, the following buffer circuit can be used to ensure that the transistor runs in the safe zone (SOA).
1) the use of the off buffer circuit is a kind of energy dissipation and off buffer circuit. Although it has more energy consumption, but the circuit is simple.
Two) 2 commonly used energy dissipation type open circuit.
A. has a non saturation reactance of the open circuit (Figure 2): the inductance – diode network with the transistor collector in series, the formation of a buffer circuit. When the tube is open, the Ls control current of the inductor is DT di/. When the tube is turned off, the energy 1/ 2 (LsI2m), which is stored in the inductor Ls, is continuously flowing through the diode Ds, and the energy consumption is dissipated in the resistance of the Ds and the reactor.
B. has a saturable reactor (Figure 3): the purpose of the opening of the buffer circuit is in order to make the transistor in the open collector current, the collector voltage drops to 0, in order to make the opening loss minimum. Especially for inductive load effect is more significant. Design of saturable reactor should be done: collector voltage drops to zero, the buffer reactor in saturation state; before saturation, collector voltage down to zero before, the reactor is high resistivity, magnetization current flowing through a tube is very small so as to achieve the purpose to reduce switching loss.

What do GND.VS+,VS-.VCO,VCI,PAR.INH mean in SCN series switching power supply?

GND: ground
VS+: half the output voltage of the power supply
VS-: dual core and dual core
VCO: voltage controlled oscillator
Identifier of VCI: virtual channel
The total solar radiation of PAR: in the range of 400~700nm
INH: no end

The function of switching power supply PFC circuit

PFC’S full name is “Factor Correction Power”, which means “power factor correction”. The power factor refers to the relationship between the effective power and the total power consumption (apparent power). The power factor can be used to measure the power of the electric power, and when the power factor is higher, the higher the power utilization ratio is. With PFC switching power supply costs are relatively high.
Switching power supply is a kind of capacitor input circuit, the phase difference between the current and voltage can cause the loss of the switching power, which requires the PFC circuit to improve the power factor. At present, there are two kinds of PFC, passive PFC (also known as passive PFC) and active PFC (also known as PFC).
Passive PFC is generally divided into “Valley” and “Fill Circuit”. The phase difference between the fundamental current and the voltage of the AC input is reduced to improve the power factor, and the passive PFC includes the silent type passive PFC and passive passive PFC. The power factor of the passive PFC can only reach 0.7 ~ 0.8, it is generally in the vicinity of the high voltage filter capacitor.
The valley fill circuit belongs to a new type of passive power factor correction circuit and its characteristics is the rectifier bridge behind the valley fill circuit to greatly increase rectifier conduction angle, through filled Valley, the current input from spike pulse becomes close to sinusoidal waveform, power factor is increased to 0.9%, significantly reduce the total harmonic distortion. Compared with the traditional passive power factor correction circuit, the circuit is simple, the power factor compensation is remarkable, and it is not required to use the large size of the large weight of the input circuit.
The active PFC is composed of the inductor capacitor and electronic components, small size, through the special IC to adjust the current waveform, the phase difference between the current and voltage compensation. Active PFC can achieve high power factor, which is usually more than 98%, but the cost is relatively high. In addition, the active PFC can also be used as auxiliary power supply, so in the use of active PFC circuit, it is often not necessary to standby transformer, and active PFC output DC voltage ripple is very small, this power does not need to use a large capacity of filter capacitor

triple output power supply

The power module system structure diagram as shown in Figure 220, it can be seen that the 1 V AC voltage signal input, first through the filter circuit module, and then sub channels to achieve AC DC voltage signal, through the DC DC/ converter is 12 V and V 10:1 DC voltage signal, and then through the V converter to get 23 +9 DC voltage signal, and the use of DC voltage integrated voltage regulator V +12 and V +9 voltage, V +5 as a reference signal, while the control circuit to provide a positive voltage. Control circuit is mainly divided into control circuit and over voltage protection circuit, control circuit is mainly used to achieve the control of the output voltage of the control, and over voltage protection circuit is mainly used to achieve the protection of over voltage, play a necessary role in the protection of three DC/DC.
1) design objectives.
The design target of the module is AC/DC power supply module, the input voltage is 220 Hz V/50 AC input, the output DC voltage is 12 V, V +5, V +9 and V. +6
(2) filtered rectifier circuit.
In order to filter out the interference in the circuit, the power input is 410-3/02 SCHAFFNER, the rated current of the filter is 3 A, the maximum operating voltage is 250 V, the frequency is Hz -25, the operating temperature is ~+100, and the average time is 675000 hours. In this power module, the filter is needed for each voltage regulator module, reference source and the output terminal of the DC voltage, so the selection of the electrolytic capacitor and electrolytic capacitor value is from 47 V to 1000 V F/16.
Rectifier bridge is selected according to the different of the rectifier circuit is divided into 220 kinds, one is the two V AC rectifier for 300 V DC circuit, the use of KBPC 108 rectifier bridge, the input voltage of V 50~1000, the input current is 3 A, used to achieve high voltage rectifier.
The other is low voltage rectification, in this circuit, the first is the 220V after the 10:1 AC power transformer, the use of rectifier bridge rectifier, the output DC voltage of 23 V.
(3) DC/DC circuit design.
In order to obtain a stable and reliable 12 V and V +5 DC voltage, the high voltage DC output of the DC/DC module is implemented in the DC/DC circuit. At the low voltage side, the V and V +9 output are achieved by using 23 V F/25 and +12 output at the input and output of each module, and the electrolytic capacitor is filtered by 100 V F/25 and 47 V respectively. At the high voltage side, three + 12 V and V +5 DC voltage are generated, and the output of the three voltage signals can be controlled by the external interface. Therefore, the VI-J61-IZ, VI-J61-IY and VI-J60-IX power supply module of VICOR is used to realize the output of 12 V and V +5. The power input of the three modules is connected with 300 V DC power supply, and the high precision of 12 V and V +5 voltage is obtained. The output control of DC/DC is required, and the In Gate of the three power modules is controlled, and the schematic diagram of the three DC/DC circuit is shown in Figure 2. In Figure 2, when the control signal is high, VT1, VT2 and VT3 work, the DC/DC 2 is not working, DC/DC and +5V are not working, and the control signal is low, VT2, VT3 and VT1 are not working, at this time DC/DC are normal, 12 V +5 and V 12V voltage output.
(4) DC voltage control circuit.
The schematic diagram of the DC voltage control circuit is shown in figure 3. The circuit is composed of two parts, which are over voltage protection circuit and the external voltage control circuit. Over voltage protection circuit mainly refers to when the input voltage is too high (or low) to produce more than (less than) 300 V after a certain percentage of the voltage, after conditioning circuit to make the voltage comparator MAX973 voltage jump, so as to change the output of the control signal, resulting in the In Gate DC/DC terminal voltage jump, and then make DC/DC stop working. The external voltage control circuit refers to the output voltage of the output terminal of the control signal changes when the external control signal input terminal is changed, thereby changing the voltage of the Gate In DC/DC, making the DC/DC stop (or start) work.
When the external control signal input is low at ordinary times, NAND circuit trigger output to a high level, at this time the counter is cleared, after counting trigger circuit and the inverter inverting control signal output for the high level so as to further verify the three DC-DC does not work, the corresponding DC / DC working indicator light does not shine. When the external control signal input is high at ordinary times, NAND circuit trigger output to a low level. At this time, the counter starts to count, after counting trigger circuit and the inverter inverting control signal output low level, so as to further verify the three DC-DC normal work and + 12 V and + 5 V output voltage, DC / DC indicator lights.

low voltage high current dc power supply

1 Introduction

In the electroplating industry, the general requirements of the power supply of the output voltage is low, and the current is very big. Power requirements are relatively high, the general is thousands of watts to tens of kilowatts. At present, such a large power of the electroplating power is generally used thyristor phase controlled rectifier. The disadvantages are the large size, low efficiency, high noise, low power factor, large output ripple, slow dynamic response, poor stability and so on.

In this paper, the switching power supply is introduced, and the output voltage from 0 to 12V and the current from 0 to 5000A can be adjusted continuously, and full load output power is 60kW. Due to the use of ZVT soft switch technology, and the use of a better cooling structure, the power of the indicators have met the requirements of the user, has now been put into production in small quantities.

2 main circuit topology

In view of such a high power output, high frequency inverter part adopts IGBT as power switching device of the full bridge topology, the main circuit as shown in Figure 1, including: power frequency three phase AC input, diode rectifier bridge, EMI filter, filter inductance capacitance, high frequency full bridge inverter, high frequency transformer, output rectifier, output LC filter, etc..

The DC capacitor Cb is used to balance the power of the transformer to the second value and prevent the bias. In consideration of the efficiency of the problem, the resonant inductor Ls only uses the leakage inductance of the transformer itself. Because if the inductor is too large, it will lead to high off voltage spike, which is very bad for the switch tube, but also increase the off loss. On the other hand, it can also cause serious duty cycle loss, which causes the current peak value of the switch device, which makes the performance of the system decrease.

3 zero voltage soft switch

High frequency full bridge inverter control mode for the phase shifted FB-ZVS control mode, control chip using Unitrode UC3875N. In the full load range, the zero voltage soft switching is achieved by the lead arm in the full load range. Figure 2. The driving voltage and the collector emitter voltage waveform of the lagging leg IGBT can be seen to achieve zero voltage turn-on.

Switching frequency selection 20kHz, this design can reduce the IGBT of the off loss, on the other hand, it can take into account the high frequency, so that the power transformer and output filter of the volume decreases.

4 capacitive power bus

In the first experiment, between the connection bus capacitor C5 and IGBT module for common power bus. In the experiment, the voltage and current of IGB on IGBT are all high frequency oscillations, and the primary voltage and current waveform of the transformer are collected in Figure 3. The reason is in parallel with the IGBT module on the surge absorbing parasitic capacitance and inductance power bus has high frequency resonance. One hour after the full load operation, power bus temperature is 38 DEG C, the capacitor C5 temperature is 24 DEG C.

5 a series of parallel transformers are used to realize the parallel structure of the output rectifier diodes.

In order to further reduce the loss, the output rectifier diodes using only current 400A, resistance to high voltage 80V Schottky diode in parallel. Moreover, the secondary output of each transformer uses a full wave rectification method. This sample is only one group of diodes that flow through the current. At the same time, in the secondary rectifier diode with on RC snubber network, to suppress by the transformer leakage and Schottky diode body capacitance caused by the parasitic oscillations. All these measures can reduce the power consumption and improve the efficiency.

For large current output, the general output of the rectifier diode in parallel. But because the Schottky diode is a negative temperature coefficient of the device, in parallel, the general should take into account the flow between them. There are many kinds of parallel modes of the diode, the graph a is the direct parallel mode, the B is a series of parallel connection mode, and the C is a series of dynamic current transformer. (the parallel connection of four diodes).

For the direct parallel method, the diode current is very poor, the output current is generally limited to tens of amps to hundreds of AMPS, not easy to do a thousand amps. In order to achieve the purpose of the current, the current can be used to achieve the purpose of the current flow. Because of the influence of proximity effect and skin effect, the average flow of the diode is changed with the output current, and the effect is poor. In order to achieve a good result, the resistance of the string is not too small, which brings great loss. For the series of dynamic current transformer, the parallel mode can achieve better results, but the production process of large current transformer is complex, the cost is high, and the leakage inductance and the lead inductance of the dynamic current transformer can be increased.

In order to overcome the shortcomings of the above parallel mode, the output rectifier diodes can achieve both automatic current sharing, reduce the loss, and can reduce the complexity of the production process, we have designed a novel high frequency power transformer, as shown in Figure 1. The transformer is composed of eight identical small transformer, the ratio was 4: 1, their primary series, while the secondary is the parallel structure. The transformer uses the primary cooling and secondary cooling method, which is considered to be different, and can greatly simplify the process of the transformer.

switching power supply plugs

Power plug is also called the power cord plug, English is plug. power used in various fields, various countries. General power plug only connected on the power cord can be used, according to the power plug the use is not the same, the power cord plug can be used in the 125V, 36V, 250V voltage, according to the difference of the current can be used in 13A, 10A, 16A, 5A, 2.5A.
Power plug can be divided into the conversion power supply plug, injection power plug and power supply plug.
Switching power plug: the power source plug standard for each country is different, for example, China’s power plug to the United States, it can not be used, it is necessary to need a conversion plug to complete the conversion. So you need to convert the power plug. The power plug is the plug of a national standard to be converted into a power plug for another national standard.
Injection power plug: injection plug is the plug and line through high temperature, high pressure, once formed, it can not be installed, so the power plug is very clear, stable, safe. On the market, the general circulation of the power supply is more than 80% of the plug.
Assembly power plug: the plug is the power cord and plug connection through the screw, but in the use of the process can be installed, so that the power of the power plug. For example, in the UK market there is a large proportion of the use of such an assembly power plug
Power plug generally can be divided into 2 core power plug, 3 core power plug and multi core power plug.
2 core power plug: 2 core power plug as the name suggests is two in sheet or a two pin, in particular in tablets or pins, each country is not the same as the standard, such as China is two insert, Europe is two round needle plug.
Three core plug: three core plug as the name suggests is plugs have three insert or three pins or is two insert or add two pins of a grounding hole. Such a structure than the core power plug complex, what standard size and diameter of pin are required and the distance between the length and the pin are considered.
Multi core power plug: this multi core power plug on the more complex, what 4 core power plug, 5 core power plug what, according to customer requirements, the use of which specific devices are based on real situation to consider.