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Buck or boost converter power supply for ADSL2+chipset (0)

ADSL2

11 May 2012
Over the years, ADSL, ADSL2, ADSL standard ADSL2+, and "Extended Reach ADSL2" gradual evolution. Increased data transfer rate to 24Mb/s, transmission distance up to 22,000 feet. ADSL2 standard requirements on downlink frequency band between 1. 1MHz． ADSL2+ is 2. 2MHz, data transfer rates significantly improve on the short phone line. Nikon Coolpix P300 Battery Charger Figures l and Figure 2 shows the different bandwidth, data rates and distances covered by the standard. When the same wiring harness in the transmission when multiple ADSL business, ADSl2+ can also be used to reduce crosstalk.

As shown in Figure 1, uplink direction for the band of 25kHz~138kHz, down to 138 kHz~2. 2 MHz。 This spectrum is divided into several carrier bands, each band is assigned a certain amount of bits. Bit amount for each carrier band depends on the signal-to-noise ratio (SNR). Switching frequency of the power supply have a larger effect on the noise floor, thereby reducing the total bit rate. Downlink frequency band extends to the 2. 2 MI-Iz in AD-S12+, we need to control all power switch frequency and its harmonics, from 138 kHz 12. 2 MHz frequency band. Ripple effects of amplitude and frequency are the same for each carrier can carry bit by the band. 2. Power of 2 MHz switching frequency has two advantages: (1) on its fundamental and harmonics are ADSl2+ of the spectrum, and (2) switched frequencies to reduce the output ripple for high peak to peak, even with low-cost ceramic capacitors Aluminum Electrolytic Capacitor or no problem.

MAXS072 power management solutions for ADSL2+

MAX5072 is specifically designed for demodulation of ADSL2+ system of power management. Its goal is to provide a simple, low cost converters. Running on top of the ADSL2+ band, and cheap AC adapter to power supply. It is a dual-output DC-DC converter. N-channel power MOSFET integrated high-end, each converter can work in 2. 2 MHz。 As shown in Figure 3, for the MAX5072 dual-output buck converter circuit of switching frequency ADSL2+ frequency. 2. 2 MHz switching frequency and highly integrated application for all types of DSL (ADSL/VDSL) provides a low cost, high bandwidth solution, Figure 4-circuit for MAX5072 dual-output buck and boost converters output voltage of input voltage range, output converter 1 2 buck converter (step-up) power supply. 3. 3V chipset provides power, 12V power line driver.

Although a single Converter output ripple frequency is 2. 2 MHz． Each converter is 180 ° RP status, input capacitance on the ripple frequency doubling. Thus reducing the RMS current and capacitance capacitor size. Figure 5 shows the switch dual buck converter input pattern waveform. Switching frequency is 2 for a single converter. 2MHz, the input capacitance on the ripple frequency is 4. 4MHz。 CHl=SOURCE2,CH2=SOURCEl,CH3= input capacitance on the ripple, CH4=CLKOUT.

Figure 6 is a two-wave buck converter with switched output to the grain. On the output capacitor the ripple frequency is 2. 2MHz, same as the switching frequency of the converter. CHl=SYNC,CH2=SOURCEl,CH3= output ripple on a 1, CH4=CLKOUT.

MAX5072 input voltage range of 4. 5 V~5． 5 v or 5. 5 V~23 V。 Power supply voltage for ADSL chipsets include 1. 2 V，1． 8 V，2． 5 v and 3.3V, there's also a line drive power supply voltage of 5 v or 12V. Two converter MAX5072 can be configured to buck or boost converter. This allows MAX5072 to be used for a variety of possible Panasonic Lumix DMC-FZ50 Battery Charger voltage transformation. When input and output pressure differential is large, requiring circuit at very low duty cycle operation. 2. Low duty cycle of 2 MHz switching frequency means that the minimum controllable on-time is very short. Minimum controllable on-time MAX5072 (tON-MINWj for the lOOns. Can be calculated with the following formula for a given output-voltage, in no case of jump pulse voltage the maximum distance allowed by people (VIN-MAX).

When input and output pressure differential is large, requiring circuit at very low duty cycle operation. 2. Low duty cycle of 2 MHz switching frequency means that the minimum controllable on-time is very short. MAX5072 the minimum controllable on-time (toN-MIN) about 100 ns. Buck and boost converters, equation (1), (2) can be calculated individually for a given output voltage, no jumping impulse under the maximum allowable input voltage (VIN-MAX).

VD is the typical Schottky Diode forward voltage drop of f 0. 35V), fSW for the switching frequency of the converter, tON-MIN to 100 ns.

Similarly, the maximum duty cycle limitations (DMAX) affects the output for a given voltage, the minimum allowable input voltage. Equation (3) can be calculated in order to obtain the required output voltage VOUT, and the minimum input voltage buck converters required (VIN-MIN).

Where DMAX for 84%,VD to at least 0. 35V。 Boost converter allows the minimum input voltage depends on the peak output voltage, current, and inductance values.

In order to reduce the problem minimum on-time loss or limit switch. May reduce the switching frequency. But two work in reversed-phase frequency converters cannot be different. At the same time, if not carefully select single frequency converter work JVC BN-VF808U Battery Charger will likely beat. In order to avoid minimum on-time and power consumption issues, MAX5072 provides a frequency selection (FSELl) pin. When FSELl grounding switch frequencies decrease to converter Converter 1 2 half of the switching frequency. Internal oscillator or frequency of one-fourth. In such a case. Converter l 1. 1 MHz, Converter 2 2. 2 MHz。 Input capacitance on the ripple frequency is Converter 1 2 switching frequency. 5 times. And sheath asymmetric waveform.



Design method for improving power load transient response performance (0)

Power load

17 Apr 2012
Since these factors lead to adjust the output voltage falls below ratings after the following, then the output voltage to the error amplifier with feedback current source IREG fully opened, forcing the output voltage back to the rated voltage. Output voltage will rise and overshoot exceeds the rated value, as the loop to continue to adjust, the output voltage will be adjusted down. In this case, very accurately reflects the phase margin of the loop (loop stability). A better compensation and phase margin greater than 40 ° loop, will result in a rapid disappearance of transient, and only contains a major offset in the transient (as shown in Figure 2). Relatively small phase margin will be in the loop on Nikon Coolpix S230 Battery Charger the establishment of an additional "ring cycle (ring cycle)". The waveforms in Figure 2 shows the best description of a stability, but it is not typical.

When the control loop reaches a new steady state (regulator current source for current is IL2), the output capacitor stops provide current to the circuit again.

Why not increase/decrease the load transient?

There are two types of load transient: sudden increase in load current, or reduced. Previous examples show that how the output voltage when the sudden increase in load current changes. The following examples will explore what happens when the load current is suddenly reduced (Figure 3).

Figure 3: current reduces the load transients

In this case, the load current to suddenly drop from IL1 IL2. As IREG does not immediately drop to the IL2, initially it will continue to provide current IL1 size. Since the load is now absorbs less current, the output capacitor must absorb the difference between IL2 and IL1, this will force the COUT on either side of the voltage rise.

If load current decrease rapidly, it produces a voltage spike in the ESL side and ESR into COUT currents will also result in a ESR step (Figure 4). After the peak, as the capacitor from the absorbed current (IL1-IL2) charge, COUT voltage will rise on both sides.

Figure 4: when a sudden drop in the load VOUT

VOUT above rise to ratings, feedback will eventually lead to control loops closed (or reduce) current source IREG. But now that most of the voltage regulator is current could not be absorbed into their output, VOUT can only follow the COUT to the load speed of discharge once again fell to rated value (IREG is reduced or closed later). However, once under the VOUT rushed to the rated value, control loops will renew efforts to open the IREG and output rise rapidly rotating, causing this cycle repeats until the new steady state conditions, at this point because the IREG is equal to IL2,COUT again if no current flows.

Load reduce set-up time is usually greater than transient load increasing transient time, this is because the former COUT load phase voltage discharge excess spending more time: as the load current demand has decreased, capacitor discharge becomes Panasonic CGA-DU07 Battery Charger even more slowly. Increased load transient COUT it most of the time is spent in the Rotary on the rise, and voltage regulator in this mode provides the most current (typically greater than the rated output current). To load and discharge is lower than when you are these currents are driven, COUT on either side of the voltage (that is, adjusting the output voltage) will change much faster.

This shows that in the majority of cases, for rated current load from 20% stepped up to a transient, its output voltage to rebuild from the rated load current to the rated value is greater than the speed of the 80% stepped down cent load transients. Even if the total load current changes the same set-up time (and the shape of wave) also showed a big difference.

Optimization of transient response

Transient response need to optimize the system for optimum design parameters, design recommendations given below.

Good steel by the most. Large-capacity ceramic capacitor is best for reducing transient capacitance in the world, most boards are placed on a large number of ceramic capacitor (capacity up to 22 μ f), these capacitors mounted directly on the pins of the device, power can be suppressed after the transient. Large capacity with ESR ceramic capacitors are usually low to Milli-Ohm resistance level, and ESL values are very low. No other types of capacitors to the ESR and ESL at provide this level of performance (despite the very low ESR electrolytic capacitors can be provided).

Need to provide a charge in the neighborhood library. Ceramic capacitors provide capacitance size there is a practical limit, so it is usually close to their ceramic capacitor electrolytic capacitors to be "backed up", the electrolytic capacitors in the initial load transients through support for loading. Tantalum capacitors are often used in this regard in the past, now because of fire hazard considerations have been avoiding the use of the symbol. POSCAP, and Panasonic and Sanyo OSCON SP electrolytic capacitors are of companies with very high capacity low ESR capacitors.

Cheap bulk capacitors. Input terminal of the regulator usually use high capacity, low cost, and aluminum electrolytic capacitors with high ESR. Because input can endure high ESR capacitor, this is caused by ESR "voltage step" does not directly affect the regulation of output voltage, instead it is regulator of "linear adjustment" function, and the functions usually input terminal of the regulator on the DC changes provide attenuation of up to 60~80dB.

Voltage regulator bandwidth. Regulator with large loop bandwidth can load more quickly adjust to change, at the same time can reduce the number of output of large-capacity capacitor, which shortly after absorption by regulators in transient storage in high capacity input capacitor charge to achieve. In General, linear regulator often significantly faster than the speed of JVC BN-VF823 Battery Charger switching speed, this is because the unity-gain bandwidth can be larger than the 500kHz of the linear regulator (although due to constraints of power, many new processor chips and high current demand load requires the use of switching converters). A always a correct conclusion is that faster means that the higher the cost, and without exception will need to increase the bandwidth high current voltage regulator.



Over voltage and over current protection, improved charging management system of security and reliability (0)

reliability, However

13 Mar 2012
For a small lightweight portable application, current members preferred the rechargeable battery is a lithium ion battery. But when it comes to mobile phones or navigation devices, portable media players, and other devices like power management, design engineers will use a well-defined set of voltage and current ranges, including as a power battery, battery charger for accurate and reliable supply of energy and linear regulator or for system power supplies DC/DC converter to convert.

However, the designer does not control power management devices used in power. The device can connect to many different kinds of power supply, regulated and non-regulated AC/DC adaptor, USB hub and port, as well as automotive and Panasonic Lumix DMC-FZ18 Battery Charger industrial power systems. These power supplies can cause a range of problems. Little is known due to external power supply, and therefore needs to be carefully designed to protect the application from unknown or unpredictable event of damage.

Application in circuits and batteries, charge modern protection schemes to protect sensitive electronics from damage to high voltage and over current, through the excellence of fast switching of voltage and current application management capabilities to provide safe and reliable charging front-end.

Single lithium ion battery charging system

Single lithium-ion batteries are typical of charging and power management applications usually consists of two components: power supply and power supply circuit. User a AC/DC wall adapter or on the computer with a USB cable to plug it in to a portable device, to provide 5V power supply voltage. In the device, power management chip on the battery charging voltage regulator and power system stabilizer. Charge management IC can be integrated with high power management unit (PMU, contains a number of DC/DC converters and low pressure drop (LDO) regulator) using a combination of separate charger. In addition, the charging function has also been integrated into PMU. Figure 1 shows a single lithium ion battery pack power system's basic structure.

Yiqian, device manufacturers to limit the applications that can be integrated into their power supply, to ensure the power adapter that came with your electronic equipment to meet specific performance requirements. USB charge and has not been widely used.

However, because of the huge cost pressures of consumer electronics products, vendors trying to simplify or cancel the power adapter power adapter and only provide a USB charging cable to reduce the system cost. In addition, the huge market allows consumers to purchase spare parts for their electronic devices of any type of power adapter. Convenient USB charging, due to its characteristics to be actual single lithium ion battery standard. Chinese Government has also called for a new production of portable electronic devices have a universal charger interface.

Because the device's external power supply does not have restrictions, power supply designer must therefore anticipate a wide variety of devices and failure modes. AC/DC adapters low price of parts and accessories in the market, even with the design specification, are not so strict. This could allow a peak of power lines (spike), or allow the simple arrival of the open circuit voltage of the transformer-type adapter charging and battery systems. Electronic component of the adapter may fail, resulting in unforeseen over voltage or over current conditions. Long distance cable inductance effect of voltage and current transients that may cause more problems. USB port and a dedicated USB charger, it may conform to the USB specification, but many times are not accurately regulated to 5V power supply voltage.

So why potential security and reliability problem? some people might think that charging circuits provide adequate security mechanisms, can withstand the power of temporary or permanent abnormal working conditions. Unfortunately, reality is exactly the opposite. The vast majority of independent charging IC (in fact includes all simulation based on the market today with PMU) have adopted the low-voltage semiconductor process, usually provide the absolute maximum voltage of 6 to 7V. For 5V system overvoltage conditions, the maximum voltage and do not provide many safety margin.

This is the problem. Only a handful of semiconductor companies have combined with high-voltage electron transistor logic of the necessary technology and highly integrated chips, to manufacture cost effective high performance charging IC target. For voltage management functions (such as audio signal processing, or touch screen control) for integrated PMU, to achieve the greatest possible integration, while maintaining the highest level of audio performance and accuracy, requires the use of small size (small-structure), low-voltage CMOS technology. However, is the price of increasing integration, maximum allowed voltage rating will decline.

Circuit and battery protection considerations

Essentially, voltage and current conditions on the front of the power conversion system might have three problems.

First, power input voltages may exceed the safe operating voltage level (defined as the circuit does not harm case, sustainable working voltage level). Second, the abnormal load conditions may result in charging or trying to power conversion circuits obtained power beyond the permitted range (within the scope of the license will not damage the power supply, or the input current of the given criteria) of current. Finally, the charger may fail, Zener voltage exceeds the safe working level for lithium-ion batteries, may cause an explosion.

Traditionally, over voltage protection is through transient voltage suppressors (transient absorbers) implementation, and transient absorption function is Zener diode for high power applications. Transient absorbers may be slow to respond, and they protect the threshold is not too accurate. In addition, their relatively large size. Dedicated integrated input overvoltage (OVP) circuits respond faster and more accurate. However, this is still insufficient to ensure overall system security and reliability, because this kind of protection is only potentially harmful working conditions possible. You can use fuses for Nikon EN-EL12 Battery Charger overcurrent protection, but transient absorption in the application, for fast transient voltage and current, response time may not be the fuse. If the permanent destruction of the circuit, you will need to return to the manufacturer for repairs. In addition to consumer safety, avoiding costly return device manufacturers seeking higher leading cause of protection measures. Provides more security and protective cover, product design should be small, low cost, and there is enough capacity to avoid permanent failure.

Circuit in Figure 2 is designed to protect lithium-ion battery from charging circuit and the impact of power failure. IC constantly monitors the input voltage and current and voltage of the battery. If the input voltage is the case, the IC will be immediately cut off switch to cut off charging circuit of the power supply. If the current situation, the IC systems within the current restrictions in pre-programmed threshold. If the current situation continues, IC will cut off after the blanking period breakover components.

In addition, the nude PIX of the IC monitors its own temperature, and becomes too hot to be cut off in the nude. Input overcurrent threshold is programmable by the user, allowing current up to 1.5A. A processor can control the circuit and circuit fault status information will be provided to the main processor. Restrictions on space for portable devices with extremely high requirements, the circuit uses only two very small 1-µ F capacitor. 2x2 mm2 in a very small package circuit package, referred to in this and the previous discrete method for using fuse and transient absorption compared to greatly reduce the size of a complete high performance protection solution.

If the AC adapter input voltage exceeds a pre programmed value (VOVP), as shown in Figure 3-green horizontal lines, as the flux components internal FET switching, circuit power supplies cut off, low FAULT pin drive. When the input voltage to VOVP – VHYS-OVP (but still higher than the VUVLO), the FET tON (OVP) interference (deglitch time) start again at a later time, to ensure a stable power supply. Voltage hysteresis is implemented to avoid rings.

Overcurrent threshold IOCP is connected to the ILIM PIN to ground resistance of RILIM program. If load current attempts to exceed the IOCP threshold, the device will be in the blanking period (tBLANK (OCP)) within the limit current, as shown in Figure 4. If the load current in the tBLANK (OCP) in time returned to his IOCP, the device continues to work. However, if the current situation continues for more than tBLANK (OCP), the FET will be shutdown tON (OCP), and the FAULT pin drive low. FET in tON (OCP) again after starting, and electricity continue to be fully monitored.

OCP occurs at a time when internal counter will be increased by one. If a charge cycle is 15 times OCP fault, the FET will be permanently cut off. Counter to zero can be removed and applied again enter a power, or through the main processor control shutdown and restart the device to the CE pin. Can easily see the fuse/transient absorption of simple application do not meet the requirements for a level of flexibility and optimization of system security.

While the safety of lithium-ion batteries usually have a dedicated circuit to protect the battery to avoid battery damage by voltage level of insecurity, but it is better to add a backup safety circuit, to ensure that the battery is monitoring and protection, battery pack protection circuit fails to avoid battery damage by the abnormal working conditions.

Figure 2 internal battery overvoltage threshold value is set to 4.35V. If the battery voltage exceeds the BVOVP threshold, the FET will be cut off, and the FAULT pin drive low. FET to start again when the battery voltage drops to BVOVP – VHYS-BOVP. Appears whenever battery voltage failure, internal counters will be increased by one. If a charge appears 15 times in the cycle of such failures, the FET will be permanently cut off. Counter to zero can be removed and applied again enter a power, device or with the CE pin down and restarted, and OCP counter clear zero samples.

In addition to protect your system against accidental damage outside of the external conditions of insecurity, the design also protects itself from damage caused by overheating. If the device is the junction temperature exceeds the TJ (OFF), you will cut the FET, and the FAULT pin drive low. FET in the junction temperature TJ fell off the temperature (OFF) minus the lag allows TJ (OFF-HYS) when the reboot to avoid errors of voltage trigger.

Usually people want to signal anomalies reported to the master system, to take further measures. FAULT PIN is an open drain output over voltage, JVC BN-VF808U Battery Charger over current, over voltage in the event. If the application is not required to monitor the FAULT pin, you can not blank.

IC startup PIN has an opening and closing device. When the CE pin is high, the internal FET is closed. When the CE pin is low, as long as other conditions of security, FET will start. Under the CE pin has an internal resistance, and can be left blank does not. Note that the FAULT pin in the CE pin is high, its function is also prohibited.

Conclusion

Modern portable devices can be charged by various types of power supply, power supply and failure mode of work is often unknown to the design engineer. Although fuse transient absorption of traditional protection circuits and provides some degree of protection, but does not meet today's small size package, low power consumption, and fast duplicate response requirements. Fully integrated over voltage, over current and over voltage circuit provides maximum security and reliability, while only consuming minimal board space, and avoid expensive returns.



The cell phone USB charging green challenges facing the (0)

phone USB charging

13 Feb 2012

Who would have thought that the mobile phone industry will affect the environment? When you think of when thinking about how to reduce the ecological pollution, may change the automotive design, or the use of green energy, will not the phone. However, we do see the mobile phone charger has created a significant impact on the environment. The mobile phone industry has begun to use the universal charging solution (UCS) to solve this problem, the UCS will change the way of the handset manufacturers to design mobile phone. This paper will achieve safe charging port factors to be considered for analysis.

A mobile phone users a year to produce about 17 kilograms of carbon dioxide, the equivalent of a vehicle traveling 111 km. This figure is not large, the object does not seem a priority in protecting the environment. If, however, from a different angle of view, you will find that the global mobile phone shipments last year amounted to 1.2 billion, each phone has its own dedicated charger. 1.2 billion mobile phone, an estimated 500 million replacement phone. Get a new phone usually make people excited, but it clearly had no JVC GZ-MG21U Battery Charger interest to replace the charger. When you realize that the mobile phone replacement cycle an average of 18 months, most of the mobile phone has a dedicated charger (including the mobile phone of the same brand) 3-4 useless phone charger will not emerge, then right at home will be surprised. In fact, the previous charger for new mobile phone the probability is only about 10%.

This is why we begin to see why governments and institutions and the well-known enterprises in the mobile phone industry set up a special organization to reduce this waste.

In December 2006, the Chinese Ministry of Information Industry promulgated a new standard, namely YD/T1591-2006 to standard wall charger and connecting cable. Each new phone released in the Chinese market must be certified to comply with the requirements of this standard.

Another significant progress is made in the last Mobile World Congress held in Barcelona in February 2009, GSMA (including five of the world's largest mobile phone manufacturer) and 17 mobile operators agreed to provide 2012 using the mini USB connector, universal charging solution (UCS).

This action is expected to eliminate up to 51,000 tons of useless phone charger. Assume an annual production volume of the mobile phone charger will cut 20%, then this industry is expected to reduce 1,300 to 22,00 million tons of greenhouse gases.

In addition to the obvious impact on the ecological, when your weekend with their families go on vacation with you no longer need to carry two or three chargers, you can find a person by a charger to charge your cell phone.

Standardization

However, in order to enable UCS to be successful, the first requirement for handset manufacturers agreed to charge the battery via the USB standard. August 8, 2007 issued by the battery charging specification version 1.0, provides for a portable device obtained from a dedicated USB charger current limit and detection mechanisms. China Communications the standard YD/T1591-2006 mobile phones released in China also made the same request.

The phone needs to detect and determine the insert is a USB charger or another terminal for data exchange (such as computers, other mobile phones, etc.). To do this, the D + and D-USB charger short-circuit (one must be less than 200Ω resistor RDCHGR_DAT). If the devices via the USB port to connect to the phone, D + line will be driven to VDAT_SRC voltage, absorbed current for IDAT_SRC. Detected in the D-line to a specific voltage (depending on RDCHGR_DAT, and IDAT_SRC), that means the phone is connected to the USB charger.

The above battery charging specification charger maximum output current must be 1.5A, maximum charger output voltage is 5.25V. The YD/T1591-2006 provisions charger maximum output current of 1.8A.

The main challenge is the protection

However, the main challenge is not charging the battery now has to improve the provisions of the standard, but the quality of the USB charger. In fact, an expensive smart phone may be connected to a poor quality USB charger, for example, did not charge monitoring, no protection, a lot of noise. If the user of the phone is broken by the external charger is unacceptable, but it is certain that, if a particular brand of phone it is easy to damage due to charging, then this gives the impression of cell phone brands will be greatly reduced.

Therefore, the mobile phone manufacturers no longer able to control the quality of the wall charger, so they need the protection circuit installed directly inside the terminal. Protect your phone than protect the charger is more challenging, for two reasons: Has integrated hundreds of Nikon Coolpix P90 Battery Charger
functions, the phone's PCB size is greatly reduced. The thickness of the protective devices must be suitable for ultra-thin mobile phone (a total of only 7mm thick) or flip phone. Protection devices can not affect the performance of the phone itself, so the leakage current must be very low.

In order to select the appropriate protective devices, mobile phone designers must conduct a risk assessment of internal charging circuit connected to the USB port.

A well-known risk of electrostatic discharge (ESD). ESD can occur at any time, regardless of whether the phone is charging. As long as the user touch the USB connector up to 30kV ESD surge voltage, it is possible to introduce the USB circuit. Many designers already know, the USB port must be able to withstand the surge voltage of at least the IEC61000-4-2 standard 4 (8kV contact discharge) devices to protect them, this is not a new risk. A large number of transient voltage suppressor (TVS) diodes on the market is sufficient to mitigate this risk.

However, if we can not rely on the quality of the USB charger, then the second attendant risk: the phone is connected directly to the indoor power line, and therefore vulnerable to the invasion of any surge voltage that appears on these transmission lines . Designers need to consider new factors. Emerged as the major source of interference in the indoor power lines:

Industry events (near the workshop, factory, etc.) or the action of an external high voltage power line (power distribution network switches, etc.) caused by the surge voltage. Due to lightning-induced surge voltage.

The most dangerous is the frequent occurrence of lightning surge. Because of the lightning surge voltage caused by power lines on is not only sensitive to very little housing being struck by lightning before. In fact, every time the lightning struck a power line or just hit the power line near the earth, in the (buried) to online booster. This wave (voltage and current) through the power cord quickly spread through the central station protective equipment, and even families of the distribution box. Then, a residual surge voltage will be directly transferred to the chips in the phone's power outlet.

This residual surge voltage characterization of lightning waveform peak di / dt. Large number of experiments and measurements have been such a surge current model into the following waveform is defined in the IEC61000-4-5 for 8/20μs pulse.

This surge voltage is more powerful than the ESD surge is a more difficult challenge for designers.

In France (550,000 km2), each year 1 million lightning hit the earth! This phenomenon is not accidental. Even if the probability of Panasonic CGR-DU06 Battery Charger
lightning hit the housing, but within one year hit a tree or on the ground around the house within a few kilometers of the probability of close to 100%.

Household appliances are less vulnerable to infringement of these surge, but the electronic equipment is very easy. Computers, televisions and other home appliances designed to be to want to insert the power lines, are well protected. Other portable devices use a dedicated charger, with appropriate protection devices or removable battery-powered. However, if a universal charger for cost reasons, can not effectively prevent this surge voltage, then the mobile phone it is easy to damage when charging.



Quality DOXIN power car inverter (0)

DC, everybody

16 Jan 2012

At present, with private vehicles in the domestic market more and more, so car inverter power supply in mobile use in DC Panasonic Lumix DMC-FP7 Battery Charger to AC converter, will bring to your life a lot easier, is a standing offer of motor vehicle electronic equipment supplies. Today xiaobian recommend to everybody loves a good car inverter.

Car inverters

Click here to view all news photos

Household appliances connected to the power output of the converter will be able to use various electrical appliances like inside the car at home just as easy to use. Electrical appliances that can be used are: mobile phones, notebook JVC GZ-HM400 Battery Chargercomputers, digital cameras, camera, lighting, electric shavers, CD machine, game consoles, handhelds, electrical tools, car refrigerator, and a variety of travel, camping, medical first aid appliances and so on.

Car inverters

Performance, enter: DC10-15V/20-30V, render: AC220V,50HZ, power: 3000W

Car inverters usability is very high, go out to work or travel it can connect to battery-driven AC electric for all kinds of Nikon Coolpix 3700 Battery Charger work, if you like, then quickly to Yantai best lap pass purchase.



Vtron: control room solution for large-screen display system (map) (0)

Vtron, Digicom, Visionpro

15 Dec 2011

Supports all standard video input signal, video surveillance information, color projector size cameras, video recorders, DVD players, and other types of video signal source may access Digicom multi-screen processor series.

At present, large-screen display system in telecommunication network management, traffic police command, traffic control, military operational command training, scheduling, and other fields of industrial production has Panasonic Lumix DMC-ZS1 Battery been widely applied in the control room, it can set to a computer, a number of different signal sources such as video and network signal, large area display shared information to meet user demand and comprehensive information.

Vtron company provides of control room large screen display system resolved programme is will international most excellence of DLP high clarity digital display technology, and projection wall seamless mosaic technology, and more screen image processing technology, and more road signal switch technology, and network technology, and concentrated control technology, of application integrated for one, formed a has high brightness, and high clarity, and high intelligent of control, and operation method advanced of large screen display system.

(A) the system composed of the following:

1, Visionpro series display mosaic wall

2, Digicom series of multi-screen processor

3, showing the wall application management system (VWAS) software

4, signal switching system (optional)

5, the Central concentration control system (optional)

(Ii) system implementation:

1, full screen, high resolution

Can a unified logical screen wall system applications to display high resolution, achieving full screen and resolution overlay, such as Nikon EN-EL10 Battery Charger display network of large, ultra high resolution full screen and so on. For example, the 6X4 of composite walls made of full wall display resolutions (1024X6) (768X4) =6144X3072 image.

2, multichannel video signal display

Supports all standard video input signal, video surveillance information, color projector size cameras, video recorders, DVD players, and other types of video signal source may access Digicom multi-screen processor series. Multiple video signals via Digicom multi-screen processor series, respectively as a window in projecting display walls anywhere on the zoom in, zoom out, moved across the screen and full screen.

3, the network signal display

Digicom multi-screen processor series provide one to four channel independent network segments, unlimited number of various computer workstations over a network connection can be anywhere on the big screen at the same time, any display network signals, and possess fast response speed.

4, each kind of signal mix show

Digicom multi-screen processor series with ultra high resolution mosaic of computer graphics, video signals and RGB signals across different types of screen display and signal superimposed display function, either window can be any signal reduces, enlarges, all the way across the screen or full screen.

5 display, multi-channel RGB, video signal pass-through

Visionlink signal processing through the use of display unit configuration, multi-channel RGB signals and video signals can Samsung TL220 Battery Charger also be, in the context of full screen by single or MN (that is, 22, 23) through zoom.

(C) the product features and advantages

1, all-digital structures

Vtron of company Visionpro integration of DLP display unit has dedicated digital RGB input ports, while its Digicom series of multi-screen processor can connect to the now popular LAN support image display and data transmission based on TCP/IP protocol.

2, the world's original GUCS screen

GUCS smooth flat screen technology allows the entire screen, displaying clear and precise images, brightness uniformity, moisture-proof dust-proof anti-reflective, perspective effects, without distortion.

3, the world's original installation technology and professional stitching technology

Integrated display unit Cabinet, when implementing a mosaic at the surface of the screen without any metal crochet, metal cladding, screws and other firmware hinder vision, display full, beautiful, box combination mosaic gap between less than 1.0mm.

4, advanced color calibration circuit

Visionpro projection movement with the world's most advanced digital trichromatic adjusting circuits, adjustable single base color for the first time, thus ensuring the whole wall color consistency and uniformity of brightness of the screen.

5, high overall system stability

Total used in all Vtron company products equipment of the same manufacturer, the system as a whole match, high stability, will not be displayed due to a number of products in the system caused unforeseen technology convergence and the future of software upgrades and other issues, avoid service disputes.

6, leading technology

Visionpro Vtron company display unit pioneered TI worldwide firm's latest 12-degree deflection angle of 0.7 "DDR DMD projection technology, can more quickly, faithfully reflecting the contrast of color. The life up to 100,000 hours, ensuring continuous system perennial.

7, the product of high market share

By the end of 2003, Vtron companies in the Mainland have successfully installed the 300 DLP digital display wall system, maintain sales and market share in the Chinese market for many years ahead.

8, truly localized response service

Perfect of after-sales service rely on Yu advanced of technology, and experience rich of engineering personnel and adequate of JVC GR-D370U Battery Charger spare parts storage, Vtron company in Guangzhou, and Beijing, and Shanghai are has customer service center, has full series service engineer more than 100 over, and are trained professional technology training, has years of engineering installed and the maintenance experience, its service quality, and efficiency, and attitude all aspects are won the general user of praised, also are peer were of appreciates.

9 and simple to maintain

Vtron of company Visionpro DLP integration display units adopting advanced modular structure design, has good scalability and maintainability, module replacement is convenient to expand access, simple, long service life, easy routine maintenance, and also greatly reduce the maintenance time.

Top 10, scalability

When you expanded portfolio, simply overlays the number of units. Additional applications (such as new networks of workstations), you can simply access it Ethernet without replacing or changing an existing processor; to expand processors, only to be based on the expansion of the number, in the processors to increase the number of shapes channel and simultaneously upgrading the software configuration.

11, superior system of economical and practical

The whole system with low power consumption and easy maintenance features, effectively reduce system maintenance costs. Overall system running save manpower costs, energy costs and material costs.



Panasonic to provide "can support mobile phones and SD" MPEG-4 authorized (0)

Panasonic, SD" MPEG-4

15 Nov 2011

Japan Panasonic will provide support 3rd generation began on September 1, 2004 (3G) phone "3GPP/3GPP2" specification and SD card "SD-Video" MPEG-4 related software encode decode software specification group "MediaArtist" series of authorization. Since transmitted between devices such as mobile phones, camcorders and Panasonic Lumix DMC-ZS1 Battery Charger digital cameras MPEG-4 opportunities there is a growing trend of video files, so use this authority to adapt to this trend. In principle, according to the number of shipped equipment manufacturers charge licensing fees. But its price is depending on the conditions are very different.

From 2003 the company began offering MPEG-4 video coding and decoding software licensing. However, this in addition to the authority of Panasonic Lumix DMC-ZS7 Battery Charger the video-related, also enhanced audio and software functionality of the file system. Depending on the following encoding and decoding software group composition: MPEG-4 video encoding software "PS-MP4EMW", MPEG-4 decoding software "PS-MP4DMW", AAC encoding software "PS-MPAEAW", AAC decoding software "PS-MPADAW", G.726 encoding software "PS-MPGEAW", G.726 decoder software "PS-MPGDAW", MP4 multiplexing software "PS-MPFEXW", and MP4 decoder software "PS-MPFDXW", ASF multiplexing software "PS-MPAEXW", and ASF decoding software "PS-MPADXW".

Under normal circumstances, MPEG-4 software cannot be applied directly to the 3GPP/3GPP2 or SD-Video device specifications. This is because on the MPEG-4 spec developed, the software appends a number of independent development of detailed specifications of the manufacturer, as well as the qualified reasons such as image size and Nikon D300 Battery Charger refresh rate. MediaArtist import all kinds of the above independent development. The company said it "supports two types of software are almost not at all".

In addition, in terms of mobile phone software, Japan 3 mobile phone operator of video, audio, and file system specifications are different. The authorized by importing the generic part broadens support aircraft operators.JVC GR-AX220U Battery Charger Support NTT DoCoMo and KDDI uses AAC audio specifications, but does not currently intend to support Vodafone AMR.



Super DV advent era of high definition full 1080P is gradually becoming a trend (0)

Super DV, high definition full 1080P

17 Oct 2011

With the increasing popularity of liquid crystal, plasma technology, high-end TV market in the current high definition television has become the absolute mainstream. In order to cater to this trend, various digital products related to the initiation of the overall move closer to HD, recently, Sony, Panasonic, JVC, Canon, Samsung has released dozens of Nikon Coolpix S570 Battery Charger digital video camera in the autumn new products, the proportion of the quantity of the products, there is no doubt that vendors have already begun HD DV as a future key directions of development. 1080i (interlaced) and 1080P (progressive scan) parallel, miniDV, hard disk, DVD discs, Blu-ray disc and a variety of media such as Flash Flash storage technology of blooming everywhere, makes this fall's high definition digital video camera market seems hilarious exception. One industry source asserted that DV HD era, has fully arrived.

1080P high definition DV trends

Many consumers to contact high definition products when manufacturers advocacy support "1080i" and support "1080P" feeling overwhelmed, especially when some manufacturers in propaganda, claiming that only supports 1080P true HD. Reporters interviewed on the matter to a manufacturer of a technician, the technical staff said, 1080i and 1080P are recognized by the international digital HDTV standard, and 1080P is a de facto standard. As used 1080i are interlaced scan, 1080P is the way-by-line scanning, so as far as image quality, far more than 1080i elite 1080P. However, are currently either China, Europe or Japan, 1080P signal source is not really there, even now many TV products already support 1080P HD specification, but in the case of no signal source, no doubt it is just a publicity stunt.

Specific to HD digital camera area, currently 1080i still is market of mainstream, since first paragraph civilian HD DV Sony FX1E was born so far, has has three years time, technology Shang has very mature, and support 1080P specifications of DV products until this year only real appears, due to by storage capacity, and coding type of limit, even has support 1080P play of Panasonic Lumix DMC-FS35 Battery Charger TV, but and 1080i compared to, advantage does not obvious, production cost also to high out many, This is not to say a 1080P high definition DV is not good, but the design is too advanced, is not very practical. The technician said, 1080i video camera has been fully meet consumer demand for HD image, but there is no doubt that 1080P HD DV would be the future trends.

DV storage technology continuously upgrade

High definition digital video camera to obtain quick development, portability, ease of use are the two had to focus on factors. From all the major manufacturers of autumn new products introduced this year, fuselage miniaturization have become a focus on the development trend of Home HD cameras, which thanks to the development of the various storage technologies.

At present, exactly what storage media will become the mainstream HD digital camera store, has been a debated issue, most manufacturers are in every direction to explore, such as Sony, have also launched after miniDV, hard disk and DVD CD HD cameras, recently launched a high definition DV based on Flash technology. Relatively speaking, miniDV although volume is large, post editing techniques are difficult, but there was a high image quality and low cost advantages; hard drive, DVD discs, and Flash DV although smaller post-processing convenience, but capacity is a bottleneck, due to the high definition image very large amounts of data, making these types of storage of DV can only record a relatively short time. From industry trends, with the development of technology, Blu-ray disc, hard drive and Flash Flash has the potential to become the mainstream of future home HD digital camera storage media.

Buy DV multifaceted consideration should be

A dazzling array of JVC GZ-X900,GZ-X900?EK,GZ-X900EU Battery high-definition digital camcorders product on the market, so how can choose? Price has been is consumer on household HD digital camera talk about up to of topic, Sony FX1E just appears of when, price had up to more than 30,000 more Yuan, in at that time only is minority enthusiasts to enjoy to of high-end models, and until appears fell below million yuan of products Hou, household HD camera market only usher has a real of gold period, now many HD camera as long as thousands of Yuan on can buy to, for economic conditions slightly better of general consumer, are can accept.



Kick off with a DSLR shooting Christmas lights (0)

DSLR shooting, Christmas lights

15 Sep 2011

Each year to Christmas, shopping malls, downtown Christmas lights are lit bright. Photographers are busy four weeks shooting carrying a tripod, full of lively fun atmosphere. This time, we will use Sony's new α700 DSLR demonstrate the earthquake, how to capture the most special Christmas lights!

All in-camera metering system is reflective metering system, the measurement is the main source of glare, not strength. Although in normal circumstances can correctly expose the photo shoot, but sometimes it will inevitably be the main color, reflectivity and Panasonic Lumix DMC-LC5 Battery Charger  other factors. For example, we have to take the Christmas lights, is high by a number of bulbs and reflective decorative composition, camera light enough that the body is reduced by the exposure. Even spend an average segment metering, if not, then adjust accordingly, all cameras will shoot underexposed photos.

Solution is very simple, just add about 1 EV exposure compensation can solve the problem. If you use flash lighting portrait photo shoot, then we must remember that the exposure compensation and flash output compensation linked to lift, so the main exposure was also affected.

Many people are accustomed to using automatic white balance, shooting, ordinary life, if you take pictures, auto white balance the kinetic energy can definitely help you easily correct the color temperature, so that shoot out of the picture there is a natural color. But shooting concerts, Christmas lights and other lighting effects focused on the theme, often using automatic white balance mode, the color fades so colorful light, because light colors are automatic white balance function to "correct" the. We can try to use daylight mode to preserve the atmosphere, the best way is to store photos in RAW format, then later in the  Nikon Coolpix 3500 Battery Charger computer software to adjust photo color temperature. α700 supplied Image Data Converter SR so that we can directly enter the Kelvin color temperature values, or choose a preset color temperature after fine tuning, so you can fine-adjust the picture so that everyone's color temperature.

In addition, α700 offers a variety of Creative Style style settings, such as Standard, Vivid, Neutral, Portrait, Landscape, etc. To take out the festive atmosphere of Christmas, may wish to use "sharp" setting, make the color more vivid picture.


In addition to the lighting environment, in fact, also some minor areas for close-up shots are worth. For example, beautifully decorated Christmas tree decoration, with glitter, small light bulb has been quite nice after. To enhance the festive atmosphere of photos on the course with a star filter, so that the light produced dazzling astral. Telescope itself is a colorless filter, lens pit covered with mesh pattern, can be point-like light scattering of the Astral. According to the shape of the grooves and the number of generated Astral, Star filter can be divided into 4 Star, 6 and 8 satellite telescope, the choice depends on what kind of telescope you have the taste of everyone. Use of satellite shots, remember to check the light can not be too dense, or photos will be too cluttered.

Christmas close-up photo shoot, not necessarily the bottom in use, the long focal length lens. Even ultra-wide-angle lens with ultra-wide angle lens close-up shots, shooting out  more exaggerated visual effect. For JVC AA-VF8 Battery Charger  example, this shot would be used SAL1118 f/4.5-5.6 super wide-angle lens, 11mm focal length with the shortest focusing distance of 25cm in the recent film, photos show a strong sense of space and perspective.


If you want to help a friend shoot a portrait photograph Christmas lights, each must be adjusted gradually to a more attractions tripod, after finishing a night photograph results may only be a few photos. In fact, now have DSLR high ISO noise is very low, while the α700 more built-in Super SteadyShot Optical Image Stabilization, effectively raising the 2.5-4 level security shutter. Use ISO 400 sensitivity and the equivalent focal length with 28mm wide-angle lens, hand-held shooting is not easy to shake.




Travel is not available when you don't know: how to make friends with a smile and the world? (0)

eyes parts, focus

11 Aug 2011

"Eyes expression" and "adequate of face light" is a Zhang excellent portrait close-up of basic conditions, shooting Shi, please to on focus placed in was photo who of eyes parts for focus, eyes and expression in the by contains of Hei, and anger, and Panasonic Lumix DMC-FZ35 Battery Charger mourning, and Le, are is capture portrait close-up Shi of focus, this can let close-up photos to people strongly of impression, and feel rendering.

Composition skills for shooting close-up is not really complicated, with camera closer to being taken as long as you can, the trouble is in fact how the stranger you just met to lay down their defense, let you close range shooting, where this is difficult. Nikon Coolpix S220 Battery Charger In order to take the most natural expression faces, recommended photographer interaction with each other as possible, let the other party will not feel pressure on the lens, even feeling like in front of the lens, to take photos of the most vivid, natural.

Of laughing children ignore the lens.

When shooting a stranger, I like to use 50mm focal-fixed-focus lens, stand in front of strangers, I have the opportunity to interact with each other, even physically contact the boot. When shooting, the other expression is perhaps stiff stiff when need to firepower, will do JVC BN-V408U Battery Charger our best to know local languages or English speaking out, or even shake hands, shoulder, smile doesn't matter, is to make each other feel your enthusiasm. As long as enough effort, even if it is not used to the camera as one's face, your enthusiasm will soon be melted; originally noted only the lens of the eye, it will gradually be transferred to you, become natural and lively. Don't forget to shutter in a timely manner at this time, capturing the most brilliant close-up look!

Oh yeah ~ catch the expression la I want!

See the smiling faces of strangers from the heart, their also followed in a good mood! When we take photos to show your sense of humor!

At the time of shooting a stranger, I like the shot to a big bright smile, when faced with serious stranger, I always use all over the number, is a must to make a good laugh at each other, cannot help but smile, couldn't help but smirk. All in all, as long as is smile: OK! Because seen strangers so happy smiling face, they will follow laughing.

See that smile, isn't it can't help but laugh? So, how to make each other laugh then?

1. release their sense of humor to infect each other

2. rich movements

3. the exaggerated expression of the action

4. white teeth

5. friendly smile

6. standard local greetings

7. timely shouted: "Smile" (English pronunciation)

8. don't laugh, go to itch scratched each other! (But see object! ）

Laughter is the kind of magic, to eliminate the distance between people, quickly put up a bridge

.

Laughter is the Nikon MH-65 Battery Charger language, heartfelt expression.

Laughter is the kind of appeal, not only their own, but can infect others.

Laughter is the kind of frequency, the frequency of people, positive thinking.

I like to smile in one of the things in life, especially on the road, when you cannot use words to communicate; of mouth goes up when I put on a smile, and the other is when you return to the same expression sth

Originally smiles is a kind of sense of smell, I smell a stranger who human touch