Cooler Master released recently a new power supply series called iGreen, currently available in three flavors: 430 W, 500 W and 600 W. We took an in-depth look at the simplest model from this new series, 430 W.
Power supplies from iGreen series have active PFC and are RoHS compliant and that’s why this series is called “iGreen,” since both features in theory help the environment. While active PFC (Power Factor Correction) provides a better usage of the power grid, RoHS compliance means this power supply doesn’t use any hazardous material listed on the European environmental law. To be honest, both features have more to do with the ability of Cooler Master to sell this power supply series in Europe than actual benefit to the environment. You can read more about PFC on our Power Supply Tutorial and more about RoHS on our tutorial about this subject.
This power supply uses a very good cooling solution. Instead of having a fan on its back, its fan is located at the bottom of the unit, as you can see in Figure 1 (the power supply is upside down). A mesh replaced the back fan, as you can see. Since the fan used is bigger than fans usually used on power supply units (120 mm), this unit is not only quieter than traditional power supplies, but also provides a better airflow.
In Figure 1 you can also see that this power supply doesn’t have an 110V/220V switch, feature available on power supplies with active PFC.
This power supply provides one 20/24-pin motherboard connector, one ATX12V motherboard connector, one PCI Express auxiliary power connector, one floppy disk drive power connector, four peripheral power connectors and four Serial ATA power connectors, see Figure 2.
As you can see in Figure 2, the wires are grouped and protected by a plastic sleeving, which helps organizing the cables inside your PC, preventing it from overheating. The peripheral power connectors use a new mechanism that is being adopted by several high-end power supplies, known as “quick release connectors.” This kind of connector provides two latches that when pressed disconnect the plug from the device with ease.
This power supply uses a very simple mechanism to convert its 24-pin main power connector into a 20-pin one, see Figure 3.
[nextpage title=”Some Flaws”]
The model we took a look is different from the other models in this series, and we are not talking about the difference in power, but in actual features. The other two models come with two PCI Express auxiliary power cords, allowing you to use the power supply with two video cards running in SLI or CrossFire modes without the need of using any kind of power adapter. Other feature missing on this model is the EPS12V power connector, which is starting to be used by high-end motherboards instead of the ATX12V connector. So if you want to have these two features, you need to buy the 500W or 600 W model instead of the 430 W one.
We also found some finishing details that make this power supply different from other high-end power supplies we’ve see around. Even though we posted “flaw” on the subtitle, what we are describing now is not really a problem but just a matter of aesthetics.
First, the plastic sleeving doesn’t come from inside the power supply, as you can see in Figure 4. So the wires are exposed while they exit the power supply housing.
By the same token the plastic sleeving doesn’t go all the way to the output connectors, see Figure 5.
We decided to disassemble this power supply to take a look inside.
[nextpage title=”A Look Inside The iGreen Power 430 W”]
We decided to disassemble this power supply to see if it internally is really different from generic power supplies. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works and to compare this power supply to a generic one.
In this page, we will have an overall look, while in the next page we will discuss in details the quality and rating of the components used.
We can point out several differences between this power supply and a low-end (a.k.a. “generic”) one: the construction quality of the printed circuit board (PCB); the use of more components on the transient filtering stage; the active PFC circuitry; the use of a thermal sensor on the power diodes heatsink for controlling the fan speed and for shutting down the power supply in case of overheating; the power rating of all components; the design; etcetera.
In Figure 6 you can have an overall look this power supply from inside.
On Figure 7 you have a better shot of the 120 mm fan used on this power supply, and on Figure 8 the circuit used to control it. As mentioned, the fan speed is controlled according to the power supply inner temperature and load.
In the next page we will have a more detailed discussion about the components used in the iGreen Power 430 W.
[nextpage title=”Transient Filtering Stage”]
The first place we like to take a look when opening a power supply to have a hint about its quality is its filtering stage. On generic power supplies this stage has only one coil, two ceramic capacitors, one or two metalized polyester capacitors and, if we are lucky, one MOV (Metal-Oxide Varistor). This power supply from Cooler Master uses four ceramic capacitors, one MOVs, three metalized polyester capacitors and two ferrite coils, plus a ferrite bead on the main power cord. At least here Cooler Master made a terrific job.
Another very interesting feature from this power supply is that its fuse is inside a fireproof rubber protection. So this protection will prevent the spark produced on the minute the fuse is blown from setting the power supply on fire.
[nextpage title=”Primary Analysis”]
We were very curious to check what components were chosen for the power section of this power supply and also how they were set together, i.e., the design used. We were willing to see if the components could really deliver the power announced by Cooler Master.
From all the specs provided on the databook of each component, we are more interested on the maximum continuous current parameter, given in ampères or amps for short. To find the maximum theoretical power capacity of the component in watts we need just to use the formula P = V x I, where P is power in watts, V is the voltage in volts and I is the current in ampères.
Keep in mind that this doesn’t mean that the power supply will deliver the maximum current rated for each component as the maximum power the power supply can deliver depends on the other components used – like the transformer, coils, the PCB layout and the wire gauge – not only on the specs of the main components we are going to analyze.
For a better understanding of what we are talking here, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses two U8KBA80R rectifying bridges in parallel in its primary stage. As each bridge supports up to 8 A continuous current, the maximum continuous current supported by the primary rectifying section of this power supply is 16 A. This stage is highly overspec’ed: at 115 V this unit would be able to pull up to 1,840 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,472 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.
On the switching section the main transistors used are two SPW20N60C3. These transistors have a maximum rated current of 13.1 A at 100° C in continuous mode or 62.1 A at 25° C in pulse mode each. They are connected using the two-transistor forward configuration.
In Figure 13, you can see the active PFC circuit controller board.
[nextpage title=”Secondary Analysis”]
But we are really interested on the secondary part of the power supply. It uses the expected configuration for a power supply using a two-transistor forward configuration, but what is odd about this power supply is that the "freewheeling" diodes (di
odes that force the coil to deliver the energy it has stored when the rectifying diode is not conducting) have specs far higher than the rectifying diodes. Usually they are identical.
For the +12 V line a STPS30L60CT Schottky rectifier is used as the rectifying diode (30 A total at 130° C) and a S60SC6M Schottky rectifier is used as the freewheeling diode (60 A total at 118° C). For our calculations we need to consider the side with the lower limit. The maximum theoretical current the +12 V line can deliver is given by the formula I / (1 – D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode (which in this case is made by two 15 A diodes in parallel, 30 A total). Just as an exercise, we can assume a typical duty cycle of 30%. This would give us a maximum theoretical current of 43 A or 514 W for the +12 V output. The maximum current this line can really deliver will depend on other components, in particular the coil used.
The +5 V and +3.3 V lines use a STPD2045CT Schottky rectifier as the rectifying diode (20 A total at 125° C) and a S40SC4C Schottky rectifier as the freewheeling diode (40 A total). For our calculations we need to consider the side with the lower limit. Using the same math as above, we have a maximum theoretical current of 29 A for each output or 143 W for the +5 V output and 94 W for the +3.3 V output.
We removed the rectifiers from the power supply and in Figure 15 you can see four of the seven power rectifiers used, the first is used by the +5VSB output and the other three are used as the rectifying diode (marked as D1). In Figure 16, you can see the three power rectifiers used as the freewheeling diodes (marked as D2).
For the +5VSB line a STPS20H100CT Schottky rectifier is used. This part has a maximum current of 10 A for each internal diode (20 A total).
All electrolytic capacitors used on iGreen Power 430 W were manufactured by Ltec, from Taiwan.
[nextpage title=”Power Distribution”]
In Figure 17, you can see iGreen Power 430 W label stating all its power specs.
As you can see this power supply has two +12 V virtual rails, +12V1 and +12V2.
On the previous page we came with some theoretical numbers for this power supply: maximum of 514 W for the +12 V output, maximum of 143 W for the +5 V output and maximum of 94 W for the +3.3 V output. They seem correct for a 430 W product.
[nextpage title=”Main Specifications”]
Cooler Master iGreen Power 430 W (RS-430-ASAA) power supply specs include:
- ATX12V 2.2
- Nominal labeled power: 430 W.
- Active PFC: Yes.
- Peripheral Connectors: one ATX12V motherboard connector, one PCI Express auxiliary power connector, one floppy disk drive power connector, four peripheral power connectors and four Serial ATA power connectors.
- More Information: https://www.coolermaster.com
- Average price in the US*: We couldn’t find this product listed on major US-based price comparison websites. According to Cooler Master, it should cost “under USD 90”.
This iGreen power supply from Cooler Master has nothing to do with low-end (“generic”) power supplies you may find on the market, as it uses high-end components and several features not found on cheaper units, like active PFC, fan speed control, an 120 mm silent fan, etc.
We were very impressed by the power rectifiers used. They are not only good quality components but also can theoretically deliver more power than the labeled power rating of this power supply. Of course other components limit the capability of this product to deliver more than what it is labeled – like the coils and transformer used.
As we mentioned, there are two main unforgivable flaws on this particular model: first, it doesn’t come with a second PCI Express auxiliary connector. Second, it doesn’t come with an EPS12V connector. If you need these two features, you will need to buy an iGreen 500 W or 600 W power supply. So the 430 W model is different from the other models included in the iGreen series. In our opinion, a manufacturer should keep all the same features for all models within a given power supply series.
The majority of competing 430 W power supplies also don’t carry these two features, however they are cheaper – and that’s the major drawback of this power supply. You can easily find competing products from Antec, Thermaltake and Enermax – just to name a few competitors – costing less, what would you make you to think twice before going for this Cooler Master model. Availability is also an issue, as we couldn’t find this product being sold in the US.