Antec TruePower New 750 W (TP-750) Power Supply Review
By Gabriel Torres on July 21, 2009
The new TruePower (TP) series from Antec is based on a DC-DC converter on the secondary, i.e., it is basically a +12 V power supply with two small power supplies in charging of converting the +12 V output into +5 V and +3,3 V. This is the same concept used on power supplies series like Signature also from Antec, M12D from Seasonic, UCP from Cooler Master and HX (750 W and above) from Corsair. These other models proved to have an above-the-average efficiency. It is important to keep in mind that Antec used to have another series using the same name, but using a completely different internal design. That is why Antec is using the word “New” after the name “True Power.”
TruePower 750 W has a 120 mm fan on its bottom and active PFC circuit, of course. It is 80 Plus Bronze certified, meaning a minimum 82% efficiency under full (750 W) and light (20% load, i.e., 150 W) loads and minimum 85% under typical load (50% load, i.e., 375 W). It is very important to keep in mind that the 80 Plus organization methodology is too generous with the manufacturers, as they measure efficiency with the power supply running at a room temperature of only 23° C, a temperature impossible to be achieved inside a computer. In our reviews we test power supplies with a room temperature of at least double this number. The higher the temperature, the lower efficiency is.
TP-750 comes with a half modular system, meaning that it has a modular cabling system but at the same time some cables are permanently attached to the power supply. The cables permanently attached to the unit are the following:
All these cables use a nylon protection that comes from inside the power supply housing.
The modular cable system has four connectors (two red and two black) and TP-750 comes with six cables, two for the red connectors and four for the black connectors. So you cannot use all cables at the same time.
TP-750 is a small unit – especially for a 750 W product –, being 6 19/64” (160 mm) deep, including the projection from the modular cabling system connectors. All wires are 18 AWG, which is the correct gauge to be used. The cables that are permanently attached to the unit measure 20 ½” (52 cm) between the power supply and the first connector on the cable and 5 ½” (140 mm) between each connector on the cable on cables that have more than one connector. The cables from the modular cabling system are a little bit longer, measuring 21 21/32” (55 cm) between the power supply and the first connector and 6” (15 cm) between connectors.
The number of cables is more than enough for you to build a mainstream or high-end PC with up to two video cards. If you want to have three or more video cards you will have to either choose a different product or convert peripheral power connectors into video card auxiliary power connectors using adapters.
Now let’s take an in-depth look inside this power supply.
We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works and to compare this power supply to others.
This page will be an overview, and then in the following pages we will discuss in detail the quality and ratings of the components used.
Here we noticed two things. First, all electrolytic capacitors are Japanese, from Chemi-Con. Second, this power supply uses a different design from Seasonic M12D 750 W.
As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.
The transient filtering stage from this power supply is flawless, providing four Y capacitors, one ferrite coil and one X capacitor more than required, plus one X capacitor after the rectifying bridges.
In the next page we will have a more detailed discussion about the components used in the Antec TruePower New 750 W.
On this page we will take an in-depth look at the primary stage of Antec TruePower New 750 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses two GBU806 rectifying bridges connected in parallel, each one being able to deliver up to 8 A at 100° C. These components are clearly 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 bridges would allow this unit to deliver up to 1,472 W without burning these components. 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 active PFC circuit two SPW35N60C3 power MOSFET transistors are used, each one capable of delivering up to 34.6 A at 25° C or 21.9 A at 100° C in continuous mode (note the difference temperature makes), or up to 103.8 A in pulse mode at 25° C. These transistors present a maximum resistance of 100 mΩ when turned on, a characteristic called RDS(on). This number indicates the amount of power that is wasted, so the lower this number the better, as less power will be wasted thus increasing efficiency.
The primary electrolytic capacitor is Japanese from Chemi-Con, which is always nice to see, and labeled at 85° C.
In the switching section, two SPP24N60C3 power MOSFET transistors are used on the traditional two-transistor forward configuration, each one capable of delivering up to 24.3 A at 25° C or up to 15.4 A at 100° C in continuous mode, or up to 72.9 A at 25° C in pulse mode, presenting an RDS(on) of 160 mΩ.
The primary is controlled by a CM6802 PFC/PWM combo controller.
Now let’s take a look at the secondary of this power supply.
This power supply uses three Schottky rectifiers on its secondary, all in charge of the +12 V output. The +5 V and +3.3 V outputs are produced by two small power supplies that convert +12 V into +5 V or +3.3 V. As mentioned this design is also used by other power supply series like Signature also from Antec, M12D from Seasonic, UCP from Cooler Master and HX (750 W and above) from Corsair.
The rectifiers used are SBR40U45CT, each one capable of delivering up to 40 A (20 A per internal diode at 150° C with a maximum voltage drop of 0.52 V). 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. Just as an exercise, we can assume a typical duty cycle of 30%.
From the six diodes available (two per component), two are used for the direct rectification and four are used for the “freewheeling” part (i.e., to discharge the +12 V coil). Thus for our math we need to consider the path with the lower current limit, which is the direct rectification path. This gives us a maximum theoretical current of 57 A (20 A x 2/0.70). This limit is for all outputs since the +5 V and +3.3 V outputs are generated from the +12 V output, as explained. If all this current was pulled from the +12 V output alone, this would give us a maximum theoretical power of 686 W. This is less than the labeled capacity from the power supply, but this is not necessarily bad, as the “freewheeling” part is more powerful (114 A) and compensates that.
On Figures 14 and 15 you can see the small printed circuit board where the DC-DC converters for the +5 V and +3.3 V outputs are located. As you can see, they use solid aluminum caps. Each converter is based on an APW7073 controller, with seven APM2556N MOSFETs, which present a maximum RDS(on) of only 7.2 mΩ.
The outputs are monitored by a PS232 integrated circuit, which supports the following protections: over current (OCP), under voltage (UVP) and over voltage (OVP). Any other protection that this unit may have is implemented outside this integrated circuit.
All electrolytic capacitors from the secondary are Japanese from Chemi-Con. This power supply has five capacitors on the modular cabling system printed circuit board, which is great.
In Figure 17, you can see the power supply label containing all the power specs.
This power supply has four +12 V rails distributed like this:
This is a nice distribution.
Now let’s see if this power supply can really deliver 750 W.
We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology.
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching how the reviewed unit behaved under each load. In the table below we list the load patterns we used and the results for each load.
If you add all the power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.
+12V1 and +12V2 are the two independent +12V inputs from our load tester and during our tests the +12V1 input was connected to the +12V1 (main motherboard and peripheral power connectors) and +12V3 (video card power connector) rails, while the +12V2 input was connected to the +12V2 (EPS12V connector) rail.
5 A (60 W)
11 A (132 W)
16 A (192 W)
22 A (264 W)
27 A (324 W)
5 A (60 W)
10 A (120 W)
16 A (192 W)
21 A (252 W)
27 A (324 W)
2 A (10 W)
4 A (20 W)
6 A (30 W)
8 A (40 W)
10 A (50 W)
2 A (6.6 W)
4 A (13.2 W)
6 A (19.8 W)
8 A (26.4 W)
10 A (33 W)
1 A (5 W)
1.5 A (7.5 W)
2 A (10 W)
2.5 A (12.5 W)
3 A (15 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
% Max Load
Ripple and Noise
Antec TruePower New 750 W presented an impressive efficiency between 85% and 86.5% when we pulled up to 60% from its labeled capacity (i.e., up to 450 W). At 80% load (600 W) efficiency was still high at 84.3%. At full load (750 W) efficiency dropped a bit, but still above 82%. Excellent.
Voltage stability was another highlight from this product. All voltages (including -12 V) were within 3% from their nominal value, whereas the ATX specification says they must be within 5%. Translation: voltages were closer to their nominal values than needed.
Ripple and noise levels were impressively low. You can see the results for test number five below. All numbers are peak-to-peak figures and the maximum allowed is 120 mV for the +12 V outputs and 50 mV for the +3.3 V and +5 V outputs.
Let’s see if we could pull more than 750 W from this unit.
Before overloading a power supply we always test to see if over current protection (OCP) is active and at what current level it is triggered. To test this we increased current on +12V2 expecting to see the power supply shutting down. We went all the way up to 33 A (the maximum our load tester can deliver) and the power supply didn’t shut down, showing that either OCP is disabled or configured at a value above 33 A.
Then starting from test five we increased currents to the maximum we could with the power supply still running inside ATX specs. The results are below. If we tried to increase one amp more on any output the power supply would shut down, showing that one of the protections entered in action.
The idea behind of overload tests is to see if the power supply will burn/explode and see if the protections from the power supply are working correctly. This power supply didn’t burn and when we tried to pull far more than it could deliver it would shut down, so this unit passed on this test.
As you can see Antec could have labeled this unit as a 900 W product, but they decided not to do so because of efficiency, which dropped below 80% during our overloading.
32 A (384 W)
32 A (384 W)
17 A (85 W)
17 A (56.1 W)
3 A (15 W)
0.5 A (6 W)
% Max Load
Antec TruePower New 750 W (TP-750) power supply specs include:
* Researched at Newegg.com on the day we published this review.
What a power supply! Terrific efficiency between 82% and 86.5%, voltages within 3% from their nominal values (while ATX spec allows them to be up to 5% from their nominal values, i.e., voltages are closer to their nominal values than needed) and practically non-existent ripple and noise.
You have to carefully research in order to get the lowest price. TP-750 is available in two versions, standard and blue. The blue version comes with a fan that glows blue when turned on and this is the only difference between the two. Even though the blue version has an MRSP USD 10 higher than the standard version (USD 169.95 vs. USD 159.95), it can be found today at Newegg.com costing only USD 120, which is a terrific price for a 750 W unit with this quality.
If you are looking for a high-efficiency 750 W power supply and can buy Antec TruePower New 750 W for USD 120 you will be making a terrific deal!