Risks of Powering Short LED Strip Directly From GPIO

There are separate issues at work here:0) The individual LEDs of WS28x LED strips are enabled by an on-board control circuit. This way the LEDs themselves are technically not directly connected to the GPIO pins. The current limit of GPIO pins is therefore not a problem. Power and data lines are separate. 1) The LED strip - to be technically correct - is therefore not powered but controlled by the GPIO pins. However if the LED strip is connected to the power pins on the 40 pin GPIO header all the current the LEDs require needs to be routed through the traces on the Pi's. 30 LEDs with 50 mA each amounts to 1.5 A in total. That should be in the realm of the possible. The max amperage of header pins is listed with 1 through 3 A (depending on which product you look) and the current rating of the Pi's 5V header pin is about 2.5 A, see Raspberry Pi Power Limitations with the caveat that the Pi Zero got no Poly-fuse; still I would argue that it is safe to assume a current carrying capacity in the same range anyways. See also: Powering WS2812B LED strip from Pi brownoutsthe LEDs are susceptible to voltage drop caused by changing CPU usage. I would not expect that to happen, unless the power supply itself cannot provide the current. According to Raspberry Pi 3 vs Pi 2 power consumption and heat dissipation we would expect a change from 0.1 A (idle) to 0.25 A (under load), add another 70 mA if WiFi changes from inactive to active, see Power consumption of Pi Zero W?. So the change is quite small compared to the LEDs' current.Best bet is to check the power supply's capacity and the wiring from the supply to the Pi (many questions here deal with low quality and low cross section USB cables).2) It is noteworthy that the WS28x have 5 V logic levels. This WS2812B datasheet list 0.

7 * VDD as minimum high level. With VDD 5 V that's 3.

5 V which is higher than the Pi's maximum high output level of 3.3 V (let alone its specified minimum high output level). The use of a 3.3V to 5V logic level converter is highly adviseable.

See also: Powering up a WS2812 led strip with different power supplies

I am trying to understand the simplest ways to power a short LED strip of 30 WS281x lights.

Most of the instructions Ive found mention using a separate power supply for the LEDs, but is it possible to simply use the GPIO outputs for power, data and ground? Im working with an RPi Zero W.

With a limited number of LEDs, I wonder if this becomes a viable option, but I would like to understand the trade-offs.

My question is sparked by flickering Ive been seeing when trying to render colors with the LEDs soldered to the RPi Zero W.

I have a suspicion that because Im attaching the LEDs directly to the GPIO, the LEDs are susceptible to voltage drop caused by changing CPU usage.

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Could the Problem still Be the Power Supply?
Could the Problem still Be the Power Supply?
I am with The Lonestar on this one, check to see if the cooling fan is working. use the laptop on a hard flat surface for better ventilation. Will it cut out quicker if it's on your lap or on soft furniture?.1. How to calculate power draw per rail, to see if Power Supply can handle the load?Your fans and CPU cooler will run from 12. All the others will run from various voltages derived from either 3.3 or 5 volts, and without the detailed specs, you cannot tell the current levels at any voltage. However, since your computed max power is 169 watts and the supply is only rated for 160, regardless of how it's divvied up you are probably in trouble. That's not to say it wo not work, necessarily, since it's entirely possible that not all the components will require maximum power and at the same time.But it's probably not a good idea trust this. Murphy's Law applies.2. Is it possible to change an older computer to a gaming computer?You would have to replace just about everything in the case, sims 3 is quite demanding on a PC so new motherboard, CPU, RAM, power supply, new graphics card, new hard drive and then you are sorted, the power supply needs changing because all nnew graphics cards that are any good for gaming needs PCI-E power conectors and atleast 24 amps of power on the 12 volt rail so if you grew up with the PC then I take it the PC will have APG graphics and old style PC-3200/DDR400 ram in it hence the ram upgrade and GPU too. Its sad to say but I would just buy a new PC. Sorry to be the bearer of bad news though.3. Is it worth upgrading my gaming laptop to a gaming PC?this really all depends tbh i mena ur laptop is still a pretty good gaming laptop and should last u another 2/3 years atleast maybe more depending the games u play b4 its outdated for gaming. if ur after a big screen then just buy a monitor and attach it to ur laptop or attach it to ur tv via hdmi cable. the advantages of a gaming pc is that it can be upgraded as u go along like the cpu,power supply,graphics etc whereas on a laptop u can only upgrade the ram and hdd which is it. therefore gaming pcs generally last longer in the gaming world but like i said urs is seriously powerful and should last atleats 2 years or even more and u can always upgrade ur ram or hdd plus its portable. gaming pcs are usually cheaper then desktop pcs. so have a look on ebay or something and see what other people are selling similer spec laptops then look into how much a gaming pc same spec or better then urs is and decide.4. Is it a good idea to place the Power Supply Unit Below the Hard disk?Lots of cases do it these days. The 'traditional' layout with the PSU on top was designed to draw in air and blow it into the processor to help the processor heatsink and fan (as counterintuitive as it seems) - modern systems run cooler, have additional fans, generally, cool the system efficiently enough that the warm PSU air is not really needed.The bottom PSU simply draws in air and blows it out to cool itself.Now, working out why your drives are failing is not that hard. You are already looking at the SMART information on the drive I hope - check what the maximum heat on them is - overheating can cause problems. Look at the age of the drives and age related variables. And well.. drives fail.I would guess overall its probably not the PSU.5. DISK BOOT FAILURE after upgrading power supplyMy PC also refused to boot without the installation disk in place, after a re-install of Windows 7 that renamed my old Windows folder to "windows.old".I was about to go for the Repair operation but decided to check the BIOS (for boot priority) first and discovered that the reinstall had somehow disabled my HDD in the BIOS. Because of this, the BIOS was saying that there was no drive present on the PC (this would be enabled once the install disk started to boot). Anyway, I enabled my HDD and the problem was solved
The Name of the Game These Days Is Technology
The Name of the Game These Days Is Technology
By JOHN HOLUSHAAUG. 11, 1996 This is a digitized version of an article from The Times's print archive, before the start of online publication in 1996. To preserve these articles as they originally appeared, The Times does not alter, edit or update them. Occasionally the digitization process introduces transcription errors or other problems. Please send reports of such problems to . THE space that will house the new offices of the Equitable Life Assurance Society at 1290 Avenue of the Americas is a chaos of construction now, with workers installing plumbing and wiring and the walls a uniform gypsum-board gray.But shortly, top executives of the company will get a preview of what their finished offices will look like, including the lighting and the colors of the walls and floors -- even the texture of the wood used in moldings. Instead of trying to visualize the final look from drawings, mockups and samples, they will watch a computerized animation of the finished project.In a society that has become utterly dependent on computers and instant communications, technology is becoming as important in the process of office design as decisions on layout and amenities. Some aspects of technology, like the computer animation, are highly visible demonstration devices. But more of it is in the largely unseen infrastructure, with the emphasis on wiring and devices to provide for an ever greater flow, and on communications and power facilities to keep operations running through almost any foreseeable calamity.''Technology drives business today,'' said Lou Switzer, whose Switzer Group is designing the 500,000-square-foot Equitable project. ''Twenty years ago computers were the future. Now you can't run a business without them. At our shop, we don't have drafting boards anymore.''AdvertisementMr. Switzer said the demonstration is chiefly a communications device for people whose business is something other than interior design. ''Sometimes when you are talking to executives, they have no idea of what you are trying to say,'' he said. ''This gives us a chance to show them what we mean.''AdvertisementThe animation gives a camera-eye view, as it moves down a hallway, through doors and into offices. The depiction can be slowed, stopped or viewed from any angle. Nor are walls and doors an obstacle; the camera passes ghostly through them into the next room.''It's a sales tool,'' said David Mandl, an architect with Meltzer/Mandl Architects. ''Now you have a way of conveying a sense of space to people who do not think spatially. It's a better way of getting your point across.''He said the renderings are effective, but require a lot of computing power, huge amounts of memory and lots of time. ''You have to do a series of views and put them together like a flip chart,'' he said. ''We did one relatively short one that consumed $17,000 in staff time.''Mr. Switzer said the data base that underlies the animation permits quick and inexpensive changes to designs if senior executives decide they cannot live with a certain color or type of flooring or an office layout.''This eliminates the messy work of changing drawings,'' he said. ''That means a real time savings and a cost savings as well. Doing it the old way would require three times as many people and a lot more space.'' Paper plans are very much in evidence at the working level, but changes can now be gotten to workers in ''hours rather than days,'' Mr. Switzer said.SHARING electronic information also cuts down on the seemingly endless meetings needed for a big project like the Equitable move, which is consolidating the company's headquarters staff from five locations in the city.''If I have to make a change in some space, I can read the documents Lou has created,'' said E. Martin Waisnor, the Equitable executive in charge of the transfer.AdvertisementSince the floors of the building are being completely gutted, the project's managers have the opportunity to put in an infrastructure that can accommodate growth in information technology. ''Every work station is being pre-cabled with Category 5 cable, which can handle voice and data,'' Mr. Waisnor said.Having a modern cable system is necessary to support the shared computer network of today, said Matthew Davis, a vice president of Tishman Technologies Corporation, an affiliate of the construction company.''In the past, when people moved into a space, one guy would have an I.B.M. with its own cable and the next guy a DEC with its own cable,'' he said. If anybody moved, you had to drag new cable.''Category 5 or universal cable looks like the telephone wires used for the last 50 years, but has been designed in such a way that it can reliably handle high speed data transmission, including video.Please verify you're not a robot by clicking the box.Invalid email address. Please re-enter.You must select a newsletter to subscribe to.View all New York Times newsletters.''Everybody uses a computer today, if only for internal messages and E-mail,'' Mr. Davis said. ''That's why we recommend a uniform cable system, so you know what you can do without additional expense.''The system is intended to handle Equitable's needs for at least the next 15 years. ''Fiber is too expensive to use on the floors,'' Mr. Waisnor said. ''The Category 5 cable is our backbone. But we are using fiber between the floors. With a very dense data environment and short runs, it is cost effective.'' Equitable will eventually occupy the 11th through 22d floors of the building, which is at the southeast corner of 52d Street.Although it is seldom mentioned directly, the bombing of the World Trade Center in 1993 clearly got the attention of facilities managers, particularly in data businesses like insurance. They watched as companies struggled to get their computers and data filed out of the building, which lost both electric power and telephones when a truck bomb went off in a basement parking garage.One company even resorted to sneaking athletic young executives into the building so they could climb the stairs to the upper floors to retrieve the paper slips used to record trades during the day of the bombing that had not been entered into a computer.As a result, Mr. Waisnor has arranged for two main electric power feeds to its space, in different parts of the building. The thinking is if a fire or some other accident were to disrupt one line, the company could keep operating on the alternate one.AdvertisementIt is also installing battery-based uninterruptable power supply, to keep its computers from crashing in the event of a blackout.''There's a whole different atmosphere since the World Trade Center,'' said J.P. Rosato, the head of C.S. Technology, a consulting company in Jersey City. ''People don't want to put all their eggs in one basket. They want dual power and they don't want it all in the same part of the core.''Many companies would like an uninterruptable power supply and a backup generator as well, although it is often hard to install a generator in New York. ''If you are doing data processing and are in the middle of a run when you lose the computer -- that's a disaster,'' said Mr. Davis.The batteries are designed to provide 15 to 20 minutes of power so the computers can be shut down in an orderly manner that minimizes the loss of data.And with the proliferation of office machines, many tenants require more power as well as more reliable power, which can be a problem for older buildings. ''Most people want 5 watts per square foot connected today, although their actual consumption will probably be less,'' said George Feddish, the director of technical services at Cushman & Wakefield. ''We checked our own consumption and it came out to 1.8 watts per foot, but some architects are still talking about 8 to 10 watts a foot.''Another service that Equitable and other high-tech tenants are seeking to make more redundant is communications. Just as it has dual power feed, the company will have two communications providers, Nynex and Teleport. And it plans to have two communications closets on each floor for further redundancy.''The investment community was the first to demand a very robust infrastructure, but now law firms and accounting firms are following as well,'' said Alfred F. Lyons, a senior vice president of Electronic Systems Associates, a division of the Syska & Hennessy engineering company.HE said that as offices become more virtual, with more employees working from remote locations, keeping communications open with the central office is more essential than ever. ''You have to look at the opportunity cost of being down,'' he said. ''If a law firm is writing a brief and the system goes down, they lose billable hours. If I go down, I disappoint a client.''This demand for advanced technology, and the host of vendors seeking to be suppliers of things like telecommunications and Internet access services, are creating problems for building managers who wonder just what services tenants will really pay for and how to provide them.Advertisement''The issues are important to landlords who are trying to figure out how to position their buildings,'' Mr. Rosato said. ''They wonder if they should provide video conferencing capability. And they worry that they might choose something that will be obsolete the day it is installed.''A version of this article appears in print on August 11, 1996, on Page 9009009 of the National edition with the headline: . Order Reprints| Today's Paper|Subscribe
Common Faults and Maintenance Process of Adjustable Switching Power Supply
Common Faults and Maintenance Process of Adjustable Switching Power Supply
Common faults of adjustable switching power supply include fuse burning, no output, high or low output voltage, poor load capacity, rectifier diode at output voltage end, filter capacitor failure, etc. So how to repair the common faults of these adjustable switching power supplies?Troubleshooting of adjustable switching power supplyGeneral process of troubleshooting of adjustable switching power supply:1) Check whether the fuse of the power supply is blown, whether the capacitor is bulging, and whether the resistance is blackened; 2) Smell whether there is "peculiar smell" inside the power supply, such as paste smell; 3) Ask the user about the use process and the operation before the power supply is damaged, integrate the information obtained from 1 and 2, and focus on questions; 4) According to the preliminary judgment obtained in the previous three steps, further operate the power supply to confirm the fault, such as using a multimeter to detect the output voltage at both ends of the capacitor when the power supply is not powered on, and check whether the switching power supply vibrates, etc.Common faults of adjustable switching power supply, specific maintenance process:Fuse burning: when the power fuse is burned, it is necessary to focus on the inspection of diodes of rectifier bridge circuit, high-voltage filter electrolytic capacitor and power switch tube. The breakdown of rectifier bridge circuit diode and high-voltage filter electrolytic capacitor or the damage of power switch tube will lead to the burning of fuse tube. (Note: the fuse will be burnt out due to the breakdown of the switch tube, and the current detection resistance and power control chip will also be burnt out.)Adjustable switching power supply fuseNo output: this situation may be caused by no oscillation of the adjustable switching power supply. It is necessary to check the switch tube intensively. If the collector of the switch tube does not get enough working voltage, the base of the switch tube does not get starting voltage, and the positive feedback circuit element of the switch tube fails, the power supply will not output.The output voltage is too high or too low: the power supply cannot stabilize the output. This fault is generally due to the failure of the stabilized voltage sampling and stabilized voltage control circuit. During maintenance, it is necessary to focus on detecting this part of the circuit.Poor load capacity: after the power supply has been used for a long time or works for a long time, various components will be aged to varying degrees, the switch tube will work unstable, the zener diode will be heated and leaked, and the rectifier diode will be damaged, resulting in the failure of poor load capacity of the adjustable switching power supply.Internal components of adjustable switching power supplyFailure of rectifier diode and filter capacitor at output voltage end: failure of rectifier diode and filter capacitor at output voltage end is generally judged by replacement method.The structure of the adjustable switching power supply is complex, and careful troubleshooting is required in case of failure. The above is not absolute and needs to be determined in combination with the actual situation.
Advantages of EPS Emergency Power Supply As Backup Power Supply
Advantages of EPS Emergency Power Supply As Backup Power Supply
EPS emergency power supply is a high-tech environmental protection product produced by applying inverter technology and adopting CPU control, digital circuit and highly integrated electronic components. It is mainly composed of inverter, auxiliary power supply, rectifier charger, battery and controller to provide secondary or tertiary power supply for class I and II loads, special important electrical equipment, fire-fighting facilities and emergency lighting. EPS is easy to maintain, unattended, fire linkage, automatic operation, remote or building intelligent monitoring, and its start-up time is 0.1s, which is much less than the start-up time of diesel generator set. The total investment is similar to that of diesel generator set.General working principle of EPS emergency power supply: when the mains power input is normal, the normally open contact of the relay is closed, and the mains power intelligently charges the battery through the charger. When the mains power is interrupted or abnormal, the controller starts the frequency converter or inverter, at the same time, the normally open contact of the control relay is closed, and the DC of the battery is transformed into AC through the frequency converter or inverter to supply the load. The machine adopts IGBT device, SPWM inverter technology and advanced intelligent CPU control. It has simple structure, reliable performance, sine wave voltage stabilization, frequency stabilization output, automatic switching and fire linkage. It is mainly suitable for evacuation lighting, accident lighting, water pump, fan, etc. The company provides centralized emergency power supply. The installation methods can be divided into hanging type, embedded type and floor type. The emergency time is generally 90 minutes.There are many specifications of EPS emergency power supply, which can be divided into single-phase 220V and three-phase 380V according to the input mode; According to the output mode, it can be divided into single-phase, three-phase and single-phase and three-phase mixed output; There are three types of installation: floor mounted, wall mounted and wall embedded; The capacity ranges from 0.5KW to 800KW; According to the service object, it can be divided into power load and emergency lighting; The standby time is generally 90-120 minutes. If there are special requirements, the standby time can also be configured according to the design requirements. Therefore, EPS emergency power supply can meet the needs of general engineering.The use of diesel generators requires a lot of consideration. When designing the diesel generator room, a series of problems need to be considered: the size of the diesel generator room, the transportation channel of the unit, the setting of air inlet, exhaust outlet and flue. In addition, the environmental protection company must be invited to carry out special environmental protection design for the diesel generator room, so as to make its noise and flue gas meet the requirements. In addition, CO2 gas fire extinguishing system must be added due to the existence of diesel generator set in fire protection design. Therefore, every time when designing the diesel generator set, we have to coordinate repeatedly, not only considering the beauty of the building, but also meeting the operation requirements of the diesel generator set.
How Do U Convert AC Power to DC Power?
How Do U Convert AC Power to DC Power?
A rectifier is an electrical device that converts alternating current (AC) to direct current (DC), a process known as rectification. Rectifiers have many uses including as components of power supplies and as detectors of radio signals. Rectifiers may be made of solid state diodes, vacuum tube diodes, mercury arc valves, and other components. A device which performs the opposite function (converting DC to AC) is known as an inverter. When only one diode is used to rectify AC (by blocking the negative or positive portion of the waveform), the difference between the term diode and the term rectifier is merely one of usage, i.e., the term rectifier describes a diode that is being used to convert AC to DC. Almost all rectifiers comprise a number of diodes in a specific arrangement for more efficiently converting AC to DC than is possible with only one diode. Before the development of silicon semiconductor rectifiers, vacuum tube diodes and copper(I) oxide or selenium rectifier stacks were used. Early radio receivers, called crystal radios, used a "cat's whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector". Rectification may occasionally serve in roles other than to generate D.C. current per se. For example, in gas heating systems flame rectification is used to detect presence of flame. Two metal electrodes in the outer layer of the flame provide a current path, and rectification of an applied alternating voltage will happen in the plasma, but only while the flame is present to generate it.• Related QuestionsHow to build VoltMeter for car battery (found circuit need help understanding it)?If the battery is discharging over a short area of time e.g. in one day then attempt disconnecting it for the evening. in the journey that your motor vehicle starts right here day then the battery is effective, if no longer the battery or battery terminals are defective. If the battery is effective then attempt right here: place an ammeter interior the battery circuit with the ignition off, any present day drain will manifest on the size. the present drawn would be a demonstration of what it is it is draining your battery. Then attempt pulling fuses separately till the present drain stops and this allow you to comprehend which circuit has a topic, from there it is an argument of discover ways to locate the subject. in case you haven't any longer have been given an ammeter then attempt pulling a number of fuses for the evening till you have stumbled on the circuit that drains your battery. maximum present day vehicles have some consistent present day draw whether it fairly is basically an alarm gadget or electronics yet those should not be sufficient to discharge a healthful battery over a short era. fairly generally hidden lights fixtures may be the wrongdoer final on once you think of they're off e. g. boot, below-bonnet or glove-field. one ingredient to submit to in techniques whilst coping with a DC electric gadget is that the situation of electric connections could be needed, examine for corrosion and tightness of battery, floor, and starter motor circuit terminals - it is conceivable for a bounce start to furnish sufficient extra skill to conquer terminal resistance issues. stable success certainly one of those great style of stable solutions and that i'm so sluggish - could discover ways to style with extra suitable than one finger!------For a buffer amplifier using op-amp, what happens if input voltage is greater than supply voltage?The input voltage range is usually specified by the input common mode range and should be within the power supply range or sometimes considerable less (as much as half the supply in some). It is a good idea to have series current limiting resistors too if the inputs can be widely separated in voltage, so that high current doesn't pass through the clamp diodes. See the internal circuit of a bipolar op-amp like a 741 on its data sheet for an understanding. Some JFET input op-amps can have the inputs outside the power supply within reason, and also have no clamp diodes. The effect of driving the input beyond the specified range depends on the individual device type, considering there are different input circuits, but the sort of effects are latchup (can be catastropic in some older designs), reversal of input polarity, loss of open loop gain, loss of common mode and power supply rejection. The simple point is that a circuit will not behave as expected. For a buffer amplifier the output is driven to saturation when the closed loop gain x input signal exceeds the output voltage limits, which are often specified one or two volts below the supply rails. This is just overdriving the amplifier as long as the inputs remain within their specified range. This is a different specification to the input voltage specification. When the output is saturated the loop cannot operate as a closed feedback loop - the loop is broken. However if the output is just driven into saturation by exceeding the input drive for that gain, the output signal is just clipped. The tops and bottoms are cut off AC signals. As soon as the input comes back in range the loop closes again and all works as expected.------Design a 10 volt power supply with the same specs as problem 2.3(I have this).?The common way is to have a current reducing resistor connected to the Collector of the series pass transistor, which has the other end of the resistor connected to the base of the same transistor. From the base of the transistor, connect the Zener diode cathode lead to the transistor base, and the series resistor, with the diode anode lead connected to ground. This establishes a constant input from the rectifiers and filter capacitors supply to the diode, and the base of the transistor. If calculated properly, the diode current will be just enough to keep it at it's break over point, and hold a steady voltage value at the base of the transistor. So long as current draw doesn't exceed the capacity of the transformer, or the transistor, it should remain linear over a wide range of loads. Worst case for the transistor would be just at the point of thermal runaway for the transistor. Once that point is reached, however, there is little chance of saving the transistor. The characteristic curves for the transistor should be consulted as these will give a lot of useful information that your problem wants to know. A good resource for such as this is the Radio Amateurs Handbook which is printed by the ARRL. Using the emitter follower design is to make a low impedance voltage output device. If the collector is used, that is the power supply is connected to the emitter, then the collector becomes the output source, and tends to be a high impedance which is a configuration used for fixed current sources.------How to design a switch mode power supply (SMPS) circuit with dual output voltages?For the best answers, search on this site A switching-mode power supply (SMPS) is a power supply that provides the power supply function through low loss components such as capacitors, inductors, and transformers -- and the use of switches that are in one of two states, on or off. The advantage is that the switch dissipates very little power in either of these two states and power conversion can be accomplished with minimal power loss, which equates to high efficiency.Usually a switching-mode power supply is circuit that operates in a closed loop system to regulate the power supply output. Although the benefits of switched-mode techniques are great, there is a penalty paid in the increased noise present at both input and output of the supply due to the power switching techniques. Also the associated control circuitry is much more complicated than its linear counterpart.The switching mode power supply contains a transformer/coil and to make this as small as possible, the internal switching frequency has to be quite high, something typically in the range between 20KHz and 1MHz. This also makes the device noiseless to human ears. The oscillator noise is often conducted onto the input and output lines with a frequency that varies with the load.There are many different types of withing power supplies.Off Line Switching Mode Power supply is a power supply in which the ac line voltage is rectified and filtered without using a line frequency isolation transformer. After rectifications and filtering the voltage is converted to the needed voltage using a swithing regulator circuit, which usually provides also isolation function (power goes though high frequency transformer). The typical PC power supplies (AT and ATX power supplies for example)are built in this way.------Why there is sudden increase in the small reverse saturation current at the breakdown voltage in diode?Reverse biased usually refers to how a diode is used in a circuit. If a diode is reverse biased, the voltage at the cathode is higher than that at the anode. Therefore, no current will flow until the diode breaks down. Connecting the P-type region to the negative terminal of the battery and the N-type region to the positive terminal, corresponds to reverse bias. The connections are illustrated in the following diagram: Because the p-type material is now connected to the negative terminal of the power supply, the 'holes' in the P-type material are pulled away from the junction, causing the width of the depletion zone to increase. Similarly, because the N-type region is connected to the positive terminal, the electrons will also be pulled away from the junction. Therefore the depletion region widens, and does so increasingly with increasing reverse-bias voltage. This increases the voltage barrier causing a high resistance to the flow of charge carriers thus allowing minimal electric current to cross the pn junction. The increase in resistance of the p-n junction results in the junction to behave as an insulator. This is important for radiation detection because if current was able to flow, the charged particles would just dissipate into the material. The reverse bias ensures that charged particles are able to make it to the detector system. The strength of the depletion zone electric field increases as the reverse-bias voltage increases. Once the electric field intensity increases beyond a critical level, the pn junction depletion zone breaks-down and current begins to flow, usually by either the Zener or avalanche breakdown processes. Both of these breakdown processes are non-destructive and are reversible, so long as the amount of current flowing does not reach levels that cause the semiconductor material to overheat and cause thermal damage. This effect is used to one's advantage in zener diode regulator circuits. Zener diodes have a certain - low - breakdown voltage. A standard value for breakdown voltage is for instance 5.6V. This means that the voltage at the cathode can never be more than 5.6V higher than the voltage at the anode, because the diode will break down - and therefore conduct - if the voltage gets any higher. This effectively regulates the voltage over the diode.
A Design Scheme of Grid Connected Led Environmental Protection Billboard Power Supply System
1. IntroductionWith the characteristics of energy saving, environmental protection and convenient installation, solar photovoltaic lighting equipment has established an important position in the lighting industry. In recent years, with the continuous improvement and development of the commercialized market, advertising has become larger and larger, and energy investment in advertising has become more and more. Based on the concept of environmental protection and energy conservation, several companies have produced solar billboards in the market, but these billboards generally do not fully consider how to maximize the energy conversion rate and service life of the battery.This paper analyzes some problems that are not fully considered by the popular controllers in the market, and puts forward a set of energy-saving grid connected led environmental protection billboard power supply system design scheme.2. Overall block diagram of grid connected led environmental protection billboard power supply systemThe grid connected led environmental protection billboard power supply system is composed of solar cell, mains power, lead-acid battery, LED lamp, driving circuit and controller. A set of basic grid connected led environmental protection billboard power supply system, and the principle block diagram is shown in Figure 1.(1) Solar panel is the main energy source of grid connected led environmental protection billboard power supply system. Its function is to directly convert solar energy into electric energy and store it in lead-acid battery.(2) The control circuit controls the charging stage of the lead-acid battery, realizes the trickle, constant current, overcharge and floating charging modes of the battery, and controls the power supply of the battery and municipal power to the LED billboard.(3) Lead acid batteries are used for energy storage for LED billboards.The system mainly achieves the purpose of energy saving from the following points:(1) The lead-acid battery is used as the energy of the control system to reduce the consumption of municipal power, so as to make full use of clean energy.(2) According to the characteristics of photoresist, the approximate charging time of lead-acid battery is controlled. Generally speaking, in good weather, at noon, the sunlight is the strongest, the light energy is the most sufficient, and the conversion efficiency of solar panels per unit time is the highest. At this time, it takes the shortest time to charge the lead-acid battery and make full use of solar energy.(3) The clock chip feeds back the time signal to the single chip microcomputer, and the single chip microcomputer controls the night working time of LED advertising lights in real time, so as to reduce unnecessary energy waste.(4) The advertising lamp adopts LED lamp, which has the characteristics of low voltage, high brightness and energy saving compared with the same power lamp.3. Hardware design of control system3.1 design of power supply module(1) Design of single chip microcomputer power supply module and cn173 special battery charging management chip power supply module of single chip microcomputer power supply module and cn173 special battery charging management chip power supply module come from 12V lead-acid battery and solar cell respectively. Lm2575t-adj is used as voltage conversion chip to obtain 5V and 15V regulated power supply respectively.(2) The standby power supply 220V is designed for the power supply module of the LED billboard by the municipal power. After step-down, rectification and filtering, the municipal power obtains the same voltage as that supplied by the lead-acid battery to the LED billboard, so as to make the LED billboard work stably. The power module circuit is shown in Figure 2.
Power Management Solution for 5g Base Station Component Power Supply
Since the introduction of analog cellular network in the early 1980s, cellular communication has gone a long way. Today, with the market moving from 4G to 5g network solutions, the cellular communication industry is laying the foundation for a great leap in data transmission speed, lower latency, capacity, user density and reliability. For example, with the 100 times improvement of data rate and network capacity (10 times), 5g also significantly reduces the delay of less than 1 millisecond, and provides ubiquitous connectivity for billions of connected devices. It is part of the continuous development of the Internet of things (IOT). Figure 1 shows a typical 5g beamforming transmitter, including digital MIMO, data converter, signal processing component, amplifier and antenna.Power FPGAIn order to give full play to the advantages of 5g, designers need higher frequency radios, new spectrum faster data converters required to meet future data capacity requirements by using more integrated microwave / millimeter wave transceivers, field programmable gate arrays (FPGA), and high-power, low-noise power amplifiers (PA) for small batteries. In addition, these 5g units will include more integrated antennas for reliable connection using large-scale multiple input multiple output (MIMO) technology. Therefore, various state-of-the-art power supplies are required to power 5g base station components.Modern FPGAs and processors are manufactured using advanced nano processes because they usually perform calculations quickly and use low voltages ( 90%), power density, low noise performance and control required by these 5g power amplifiers.Facing the great pressure of the next generation (5g) products, its performance is better than that of the previous generation (4G), so there is almost no room for compromise. Therefore, ADI focuses on all aspects of the base station RF chain and has a comprehensive knowledge of the power management tools required to power these applications, which can provide appropriate power for today's 5g based power amplifiers and transceivers. Provide the industry's broadest range of high-performance power by linear ™ The product portfolio includes high efficiency, high density DC-DC converter module, power management IC (PMIC) and ultra-low noise linear regulator, including power sequencing, monitoring and protection. ADI can provide a more comprehensive method for 5g signal chain.ADI μ Module regulator and mute switcher services are complete power system level packaged solutions that can provide accurate voltage. The micro package has the highest efficiency (> 95%) and power density, high reliability and minimum EMI and noise. These solutions are designed for high-performance RF systems with the highest power conversion efficiency and density without adding noise or interference to radio signals of interest, thereby ensuring the best performance of these RF PAS and other such RF circuits.Similarly, in order to solve the challenge of power sequencing in circuits requiring multiple power rails, ADI has established a series of sequencers from two power supplies (adm6819 / adm6820) to 17 channels (adm1266). In order to ensure the correct, efficient and safe operation of the system, it is very important to monitor the equipment voltage, current or temperature. For this purpose, ADI provides components similar to ltc2990.closeIn short, ADI's power by linear product series includes low-noise LDO regulator, low EMI and highly integrated multi coil DC-DC converter μ Module devices, mute switcher technology and other power management ICs, including power sequence generator, monitor and protection circuit - all of which make ADI the most extensive power product series in the industry. It includes everything needed to power 5g base station components, including software design and simulation tools such as ltpowercad and LTSpice. These tools simplify the task of selecting the appropriate power management solution for these devices, thus providing the best power solution for 5g base station components.
How to Understand the FET Commonly Used in the Design of Switching Power Supply?
To get down to business, I'm afraid I don't need mapping when it comes to the appearance of FET. It's often used in circuit diagramsBecause its construction principle is relatively abstract, we talk about its use in a popular way, so we won't talk about it more. Because there are many kinds and different characteristics according to the requirements of different occasions; In MPN, we usually use it as an electric control switch powered by power supply, so the current needs to be relatively large, so we use a special manufacturing method to make an enhanced field effect transistor (MOS type). Its circuit diagram symbol is:If you take a closer look, you will find that there seems to be a difference between the two diagrams. By the way, these are actually two different enhanced FET. The first one is called n-channel enhanced FET and the second one is called p-channel enhanced FET. Their functions are just the opposite. As mentioned earlier, the FET is a switch controlled by electricity, so let's talk about how to use it as a switch. From the figure, we can see that it also has three pins like a triode, which are called gate (g), source (s) and drain (d). The schematic diagram of patch elements in MPN is like this:Pin 1 is the grid, and this grid is the control electrode. Add voltage and no voltage to the grid to control the connection and non connection of pin 2 and pin 3. For channel n, add voltage to the grid, pin 2 and pin 3 will be powered on, and the voltage will be turned off when the voltage is removed. On the contrary, for channel P, add voltage to the grid to turn off (high potential) and remove the voltage (low potential) to connect.The p-channel MOS transistor is often encountered in the power on circuit in our common 2606 main control circuit diagram:Si2305 in this figure is a p-channel MOS tube. Because many friends are confused about checking this part of the fault, it is necessary to talk about its working principle here to deepen your impression.In the figure, the positive power of the battery is connected to the 2-pin source of FET Q1 through switch S1. Since Q1 is a p-channel tube, its 1-pin grid provides a positive potential voltage through R20 resistance, so it can not be powered on, the voltage can not continue to pass, and the 3V voltage stabilizing IC input pin can not get the voltage, so it can not work and can not be started.At this time, if we press the SW1 start button, positive electricity is added to the base of transistor Q2 through the button, R11, R23 and D4, the base of transistor Q2 gets a positive potential, and the transistor is turned on (as mentioned earlier when talking about the transistor). Since the emitter of the transistor is directly grounded, the conduction of transistor Q2 is equivalent to the direct grounding of the grid of Q1, The voltage applied to it through the R20 resistor directly enters the ground, the gate of Q1 changes from high potential to low potential, and Q1 is energized from Q1 to the input pin of the 3V voltage stabilizing IC. The 3V voltage stabilizing IC is the 3V working voltage Vcc output by U1, which is supplied to the main control. The main control inputs a control voltage to PWR through a series of actions such as resetting 0, reading firmware program detection, etc_ On is then sent to the base of Q2 through the partial voltage of R24 and R13 to keep Q2 in the on state. Even if you release the start key to disconnect the base voltage of Q1, Q2 can always be in the on state when the control voltage sent by the main control is maintained. Q1 will continuously provide working voltage to 3V voltage stabilizing IC! SW1 also sends control signals with different length of time and times to the main control play on pin through the partial voltage of R11 and R30 resistors. The main control outputs different results to the corresponding control points through firmware identification of play, pause, startup and shutdown, so as to achieve different working states.Most of the common field effect transistors in MPN are p-channel, and the printing marks often seen on it are: a2shb, 212t, 212n, 076a, aogh, n57t, r1sg, s016j, s026i, etc.The above figure is a circuit diagram with master control to control whether the earphone has sound output. The left and right channels of sound are sent to the earphone hole through DC isolation capacitors C13 and C14 and resistors R51 and R52 respectively, but an n-channel MOS FET is connected between resistors R51, R52 and the earphone hole. The gates of this FET are connected together and controlled by mute, When the mute is at a high potential, Q4 and Q5 are turned on, and the sound will enter the ground through Q4 and Q5, and there will be no sound in the headset. When the mute is at a low potential, Q4 and Q5 are turned off, and the sound will only sound through the headset.The figure above shows the common power on circuit of Ruixin micro 2608 master control. What is the difference between it and the power on circuit of 2606 master control? Did you find that there is one more MOS FET than the power on circuit of the 2606 master? What is the difference between the FET connected to the two sources and a FET in the 2606 boot circuit?The gate control of FET has a principle: the gate control voltage of P channel must be relative to the high and low potential of source input, so the source and drain cannot be connected reversely in the circuit, that is, the source must be connected to input and the drain must be connected to output. If it is connected reversely, it cannot work normally. In MPN circuit, when USB is connected, The battery power supply must be cut off immediately and replaced by USB power supply in order to work normally. If the battery power supply cannot be switched, the USB will not work normally (unrecognized). The circuit switching command of 2606 main control is issued by the main control, which uses battery power control, i.e. battery circuit, so it can be controlled with a field effect.Take a closer look at the 2608 circuit. The power switching is controlled by the triode Q7. The on and off of Q7 is controlled by the USB voltage. This is another group of power supplies. This group of power supplies can't control a polar FET. Therefore, we use two MOS FET, and the sources are connected to form a non-polar FET to achieve the purpose of dual power supply control.You can refer to my article "talking about the principle of MPN lithium battery protection board". Since the protection action of lithium battery protection board is often controlled by two groups of power supplies - internal power supply and charged external power supply, the commonly used 5n20v is an n-channel dual field effect combination block, and its principle is the same as that of the FET connected to the two sources here.In MPN, triodes are mostly used as electronic switches, which has a feature to judge: 2 pins (NPN type) or 3 pins (PNP type) are grounded, and none of the FET pins is directly grounded! The voltage stabilizing IC is absolutely grounded at pin 1, positive input at pin 3 and voltage stabilizing output at pin 2. But note that this is only general, not absolute!
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