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Hello Everyone,
Antec would like to announce that we will try to increase our customer service by becoming a forum member. We hope we will also have our forum link up soon so that we my continue to improve our availability in answering questions.
With that said, we would like to provide you with information on PSU Basic Knowledge. Thanks for your support.
Q:What is Universal Input?
A:Universal Input means that the power supply (PSU) can be used in any country around the world, with any input voltage from 90~240VAC, without adjusting an input power selector switch.
Q:What is Active PFC and what are the benefits?
A:Without Power Factor Correction (PFC), the normal power factor for a PSU is less than 0.6, which makes it more difficult for the power plant to distribute electricity. Passive PFC can boost the power factor to around 0.7, but that is not a significant improvement. Active PFC can achieve 0.99 and increase the efficiency of the power plant 40%. This is very important in an environmental friendly era.
Q:What is the purpose of electromagnetic interference (EMI) filtering in a power supply?
A:An EMI filter is a required circuit for a PSU. The better the PSU, the better its EMI filter will be designed. The filter’s first job is to prevent the PSU noise from interfering with other electronic devices. Second, it prevents electromagnetic noise from the power grid and other devices from getting into the PSU. When using a bad PSU, there can be “snow” on the monitor and any nearby TV, or there may be static on the radio.
Q:What are Double Forward Converter circuits and their benefits?
A: Double Forward is the current mainstream of PSU design. It is has many advantages such as high efficiency, low failure rate and high Wattage. The design that it replaced is called Half-bridge. The old design had the advantage of low cost, but the wattage and efficiency could not be improved. Only low end systems are still using Half-bridge design.
- When the circuit is off, each transistor is subject to half the load present in older designs.
- When the circuit is goes into its off-state, leakage inductance spikes are clamped.
Q:What are the benefits of Double Layer circuit board design?
A: Double Layer has several benefits. The only drawback is higher cost.
- An increase in copper foil area decreases loss in current flow.
- Makes printed circuit board (PCB) layout easier and components can be arranged better.
- Fewer jumpers, faster component insertion and easier board assembly.
- Prevents solder cracking when using heavy components.
- Better EMI performance.
Q:For an induction coil, what is the effect of the cross-sectional area of the copper cable?
A:Coils are measured by inductance. For two coils with the same inductance, it is better to use thicker wire. And with the same wattage, it is better with larger adaptor, larger induction coil or larger copper wire.
Q:Is the capacitor an important factor to the life circle of PSU?
A:Capacitors are probably the single most critical component. Using high capacity, high voltage ratings, and low ESR capacitors can greatly improve the PSU life circle. Selecting components with high heat ratings will also enhance the longevity of the unit. Some of the best quality components are of Japanese manufacture.
Q: Does the temperature inside the PSU affect the output efficiency and life circle?
A:Temperature greatly affects the life circle of many components, such as capacitors, resistors, fans, etc. If the temperature increases 10°C, the PSU’s lifetime will decrease by half. For example, if an output capacitor normally has a 3000 hours lifetime at 105°C; then at 95°C it can work 6000 hrs; and 96000 hours at 55°C. For efficiency, it is a different situation. Some components have higher efficiency at low temperature and some perform better when hot. For example, metallic oxide semiconductor field effect transistors (MOSFET) have higher efficiency at lower temperatures.
Q:What are the differences between DC to DC circuit and general Magnetic Amplifier Circuit?
A: DC to DC is going to be the main stream for future high-end PSU, and has the following benefits:
- Since all of the 12 volt rails and other independent voltages ultimately start from a single 12V power supply, the min. load of 12V, 5V and 3.3V can be very small or zero. Because there is no min. load, it will not cause compatibility issues in different systems. Since 5V and 3.3V are transferred from 12V, there are always indirect load to 12V from one of each.
- Antec has many power supplies designed with a main 12V core that gets broken out for separate rails. Since all power in our DC to DC design flows from the primary 12V core, all of the voltage rails can share from the same input pool of current for an optimal distribution of power at all times and across all voltages.
- The DC to DC module uses low voltage MOSFET transistors which have low on-state loss. When transforming 12v to 5v or 3.3v, Magnetic Amplifier Circuits have 70 – 80% efficiency, but DC to DC can reach 90% or higher. It is more environmental friendly.
Q:How is a pulse-width modulation (PWM) fan quieter than a regular fan?
A: PWM fans can run from 15% to 100% of their maximum speed. However, a traditional voltage control fan can only run from 35% to 90% of its maximum speed. Using a PWM fan and running the PSU at 50% load or less, the PSU will be much quieter. Any power supply running at high load will need to run its fan at high speed and will be audible.
Q:What is synchronous rectification and what is its effect on the overall efficiency of the PSU?
A:Synchronous rectification uses low voltage MOSFETs instead of a general rectifier, so its on-state resistance is lower. Synchronous rectification has lower loss so less heat is generated and efficiency is improved.
Q:What is the effect of using DC to DC on the output voltages?
A:The working frequency of a DC to DC voltage regulator module (VRM) is much higher than a Magnetic Amplifier Circuit. That means a DC to DC circuit can provide transient response times as low as 10 microseconds on rails controlled by the VRM. That’s a hundred times faster than standard power supply response times of 1 millisecond (1000 microseconds). This makes the output voltage more stable on the 5v and 3.3v rails, even if the load changes rapidly, and helps protect sensitive components.
Q:Are multiple +12V outputs PSU more stable and reliable than single +12V output PSU?
A:Multiple +12V outputs are mainly used for safety protection. Each output keeps the current within a safe range. Single +12V output is an old design; it is used to avoid wrong activating of protection circuit by mass power consuming from video card. However, it is very dangerous, because when short happens in any component; there will be no over-current protection. It is easy to cause fire, so Antec’s PSUs use multiple +12V outputs to avoid this danger. Some companies try to perpetuate a myth that power can be “trapped” on a rail. That’s just wrong. Each rail has its own circuitry for the protection of the PSU and the devices connected to it, but there’s no way one rail can limit the total power available on the others.
Q:In regards to the size of DC output cable, is bigger always better?
A:Basically, yes. However, there is still a cost/performance value which should be met and there are also electrical limitations of other components in your computer. Where larger amounts of current are required by components such as graphics cards, multiple wires tend to be used instead of one huge wire. One of the reasons for that has to do with how much current can flow into a motherboard or other printed circuit board at a single point. You gain more contact surface area for lower resistance and more connectors increase reliability of the connection due to redundancy.
Q:What is the 80 PLUS® standard?
A:From the 80 PLUS website, the 80 PLUS program is a unique forum that unites electric utilities, the computer industry and consumers in an effort to bring energy efficient technology solutions to the marketplace.
The 80 PLUS standard has four classes: Standard/Bronze/Silver/Gold. Below is the information table. The basic principle is the efficiency must be at least 80% when the PSU is running at 20% load or higher.
Fraction of Rated Load 20% 50% 100%
80 PLUS 80% 80% 80%
80 PLUS Bronze 82% 85% 82%
80 PLUS Silver 85% 88% 85%
80 PLUS Gold 87% 90% 87%
Q:Is dual PCB better than single PCB?
A:Yes. Dual PCB designs have more flexibility to arrange components and create an efficient air flow. Compared to single PCB, it will have better cooling efficiency.
Q:How do I pick a good PSU?
A:It is not easy for a general user to judge if a PSU is good or not. Here are some principles.
- Choose a well-known brand.
- Has the PSU passed safety certifications?
- Is the wattage number the value for peak output or continuous output? Continuous is better.
- Compare the weight with other similar products to see if it is too light.
- (Not suitable for passive PFC power supply)
- Compare the internal components, if they have size difference.
- Does the PSU have the 80 PLUS certification.
Q:What is the meaning and differences of working temperature of a PSU?
A:Generally the working temperature of PSUs in the market is around 25℃ (environmental temperature). However, inside a case, because of CPU and video card, the temperature is usually higher than 25℃ (environmental temperature).
Q:Why is Antec’s Signature PSU more expensive than other companies’ products?
A:Antec started to design this series based on server standards, and then went beyond. All the components are the best choices and we also added many new designs seen here for the first time in a consumer power supply. The highest quality components. Insane levels of craftsmanship. Brilliant design. Cutting edge features. Put all of that together and you have the power supply equivalent of a high-end race car. Car companies build race cars in order to push automotive technology to new heights. Tough reviewers have noted that the Signature excels in absolutely every aspect of performance, and several reviewers have said that they have never seen a better PSU, ever. It’s also built to last; at 50℃ and running 24 hrs. at full load, we guarantee it for five years. Based on performance, this is not an expensive PSU. Think of it as a race car that you can afford!
Q:Why are there so many models of PSU with the 80 PLUS label when there aren’t anywhere near that many power supplies listed on the 80 PLUS website?
A:To avoid fake certification, please check with the 80 PLUS official website to see if the products are on the certificate lists or not.
1.Some companies will also change the hardware design to pass the certification, and then the products they send to market don’t meet the standard. Here are some of the tricks:
- Cable length of test unit is shorter than the real product.
- Thicker wires are used for testing. After passing the test, the design is changed.
- Better electronic components are installed in the units sent for testing (or units are tested and hand-picked).
- Use better fans and heatsinks or adjust the fan voltage in the cooling system.
- Change EMI design or add jumper under it.
2.It is really difficult for users to determine the internal design. The best way to choose is to select a well-known brand, do comparisons and read reviews.
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Re: PSU Basic Knowledge
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