PSU Basic Q&A

[Frank Lee]

PSU Basic Q&A


1. How do I pick the right PSU for my computer?
Many factors should be taken into account, including CPU type, graphics card requirements, and what exactly you will be using your PC for. To help users choose the most suitable PSU, Antec has created a website where users can calculate how much power they need for their individual system. Please visit www.antec.outervision.com.

2. What is the easiest way to judge a PSU?
It’s not always easy to tell whether a PSU is good or not, but here are a few tips:

1. Check the label for Max Output Wattage.
2. If there is only a Peak Output number, that is a sign it may not be a quality PSU.
3. Do not assume that model number corresponds with wattage. Again, always check the Max Output Wattage.
4. Keep an eye out for safety certifications, 80 PLUS® certification, NVIDIA™ SLI™-Ready certification, and warranty information.

3. What is Universal Input?
Universal Input is another term for “full range.” A PSU with Universal Input can be used in any country around the world within VAC90V~240V, without having to adjust the input power select switch.

4. What is Active PFC?
Active Power Factor Correction improves the power factor value of the PSU by altering the input current wave shape. PSUs with Active PFC can achieve a power factor of 0.99, while PSUs with Passive PFC can only achieve 0.70, and PSUs with no PFC achieve less than 0.60. A higher power factor reduces transmission losses and improves efficiency for power companies, making Active PFC an important feature for the environment.

5. What are the benefits of EMI filtering?
EMI (Electro Magnetic Interference) filters are a required circuit for PSUs, and in a good PSU the EMI filter is well designed. An EMI filter prevents PSU noise from interfering with other electronic devices, and vice versa. With poorer-quality PSUs, it is common to experience “noise” from screens, TVs or radios when turning on your computer.

6. What is Advanced Hybrid Cable Management?
Today’s PSUs currently feature three types of cable management:
Traditional PSU: All cables are connected directly to the PSU, including extra cables. The advantage is lower wire-transmission loss; the disadvantage is cable clutter and reduced airflow/cooling.

1. Modular PSU: All cables are connected to the PSU via connectors or “plugs.” The advantage is better cable management for airflow and cooling; the disadvantage is high wire-transmission loss.
2. Antec’s Advanced Hybrid Cable Management PSU: Combines traditional PSU and modular PSU design; all necessary cables are permanently connected, while any extra cables are modular. This achieves low wire-transmission loss as well as better cable management for airflow.

7. What is 80 PLUS®?
80 PLUS® certification is the most widely recognized independent standard in power supply efficiency. An 80 PLUS® certified PSU uses less energy and generates less heat to stay cooler, run quieter and last longer. 80 PLUS® certification lowers your operating costs and helps protect the environment. There are four levels of certification based on efficiency at varying operating loads:

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%

8. Does temperature affect your PSU’s output efficiency and life span?
Temperature greatly affects the life span of many components in your PSU, including your capacitors, resisters and fans. Generally speaking, when temperature decreases 10°, your PSU’s life span will increase by about double. For example, if your output capacitor normally has a 3,000-hour life span at 105°, at 95° it will last 6,000 hours. However, for output efficiency, the same rule of thumb does not apply. Some PSU components achieve higher efficiency at lower temperatures, while others are the opposite.

9. Does capacitor mass affect the life span of a PSU?
Yes, capacitors are a major factor when it comes to the life span of your PSU. High-capacity, high-voltage, low-ESR capacitors can greatly improve your PSU’s longevity. Also, Japanese capacitors tend to feature higher quality parts and build.

10. What is “working temperature” and how does this affect a PSU?
In general, a PSU’s environmental temperature is around 25°C. In a case, because of components like your CPU and video card, the working temperature of your PSU will usually be higher. Therefore, unless otherwise noted, the actual wattage of your PSU will be lower.

11. How does a PWM fan affect fan speed and quiet?
Pulse Width Modulation (PWM) fans can reduce maximum fan speed to within 15% and 100%. Meanwhile, traditional voltage-controlled fans only reduce to within 35% and 90%. Using a PWM fan at under 50% load will result in a significantly quieter, cooler PSU.

12. What are the benefits of a double layer PCB?
A double layer PCB (printed circuit board) possesses several important benefits:

1. Increased copper foil area and decreased loss of mass current flow.
2. Wiring is made easier and components are better organized.
3. Protection against solder cracks from heavy components.
4. Lower EMI interference.

13. What are the benefits of Double Forward Converter circuitry?
Double Forward Converter circuitry possesses several key advantages compared to Half-Bridge circuitry: higher efficiency, lower failure rate and higher wattage.

14. What are the benefits of DC to DC circuitry?
DC to DC modules possess important benefits regarding the stability of your PSU:

1. There is no minimum load for 12v, 5v and 3.3v. Since 5v and 3.3v are transferred from 12v, there is always indirect load to 12v from each. And because there is no min. load, there will not be compatibility issues with other systems.
2. The working frequency of DC to DC circuitry is higher than Magnetic Amplifier circuitry. Therefore, a PSU with DC to DC circuitry can provide more stable voltage to motherboard chipsets and memory.
3. The DC to DC module uses low voltage MOSFET which has low on-state loss. When transferring 12v to 5v or 3.3v, Magnetic Amplifier circuitry has 70 – 80% efficiency, while DC to DC can reach 90%.

15. Will a DC to DC module at +3.3V & +5V stabilize the output voltage of +3.3V, +5V and +12V?
Yes, a DC to DC module can stabilize load regulation, and affects 3.3v and 5v more than 12v.

16. Are PSUs with multiple +12V outputs more reliable than PSUs with a single +12V output?
Yes, multiple +12V outputs are used to ensure safety protection; each output keeps the current within a safe range. PSUs with a single +12V output generally tend to be older designs and present greater risk because, in the event of a short in any component, there is no over current protection.

17. For a copper cable’s cross-sectional area of induction coil, is larger always better?
Generally speaking, yes. Induction coils are measured by inductance. With equal inductance, it is better to use thicker, enameled wire. And, similarly, with equal wattage, it is better to use a larger adaptor, larger induction coil or larger copper wire.

18. Does synchronous rectification to +12V increase overall PSU efficiency?
Synchronous rectification uses low-voltage MOSFET and, compared to general rectifiers, possesses lower on-state resistance. Therefore, synchronous rectification results in less loss and improved efficiency.

19. When dealing with the cross-sectional area of your DC output cable, is larger better?
Generally speaking, yes. However, as with most performance products, cost/performance should be evaluated beforehand.

20. Does a Dual PCB layout have better airflow than a Single PCB?
Yes, a Dual PCB layout features more internal space for components, creating a straight-through air tunnel with less air resistance.

21. What are the benefits of low ripple and noise?
Low ripple and noise have the following benefits:

1. Motherboard components are more stable; chip set and memory crashes are less frequent when interference of noise is lower.
2. Audio component output on your motherboard is purer when interference of ripple and noise is lower.
3. “Moire” and flicker effects on your display are minimal.
4. Disconnection and “choke” issues of WLAN/LAN are minimal.
5. For overclocking, the purer power from low ripple and noise is vital.

22. Why is Antec’s Signature Series more expensive than other PSUs on the market?
Antec’s high-end Signature Series is designed according to server standards. All components are premium, and many innovative new designs are featured. At 50°C at 24-hr full load, Antec guarantees at least a five year life span, making its cost/performance lower than expected. The Signature Series includes the following features:

• Filter Capacitors of the Primary:
• Two Japanese RUBYCON 390UF/450V/105°C capacitors provide high-voltage/high-temperature/long lifespan. Standard capacitors in regular PSUs can only stand 400V and only feature one filter capacitor.
• Filter Capacitors of the Secondary:
• Capacitors manufactured in Japan ensure low-ESR/Hi Ripple current and a long lifespan.
• Double Ball Bearing PWM Fan:
• Manufactured by well-known Japanese brand Nidec, this double ball bearing PWM fan is quieter, longer-lasting, and more stable.
  
• DC to DC Module:
• Manufactured by renowned component provider, Intersil, this server-level Direct-MOS is a high-stability SMD capacitor.
• Efficient Cooling & Air-Flow Design
• Better arrangement of components lowers air resistance. The Dual PCB design can average distribution of drag and, because of air pressure and temperature differences, airflow will travel mainly through high-temperature components. Therefore, cooling is even more efficient.

23. How can I be sure that a PSU with an 80 PLUS® logo really passed certification?
To avoid fraudulent certification, check the 80 PLUS® official website to see if the product is listed: 80Plus.com. Sometimes, companies will change specs to pass certification. While it is difficult for users to identify these misleading PSUs, some ways to protect yourself are to always choose well-known brands, do comparisons and read reviews.

24. How do Antec PSUs pass safety certifications in so many different countries?
Antec designs PSUs with three principles in mind: true output wattage, safety, and low EMI radiation. Because safety is such a high priority for Antec, it is able to earn many safety certifications, including: UL, CUL, CE, TUV, CTICK, CCC, FCC, CB and BSMI. Some PSUs on the market feature poorer designs and may not pass these safety certifications. Make sure to check the box for certifications when buying a PSU.

[Barry]