[nextpage title=”Introduction”]

From time to time, we like to buy power supplies below USD 30 to see how they stack up against more expensive models from better-known companies. The TiVECO TVPS450, which is also sold in the US as ePower TVPS450, is a 450 W power supply that costs only USD 20, with the manufacturer promising that it can deliver its labeled wattage at 50° C and 80% minimum efficiency. Is that really true? Let’s find out.

Let’s start with the product box. As we will discuss throughout this review, the feature list is the product of a very fertile imagination. In plain English, this manufacturer is a liar. For now, let’s discuss bullet number five in that list, “Auto switching circuitry provide (sic) universal AC input 90 ~ 264 V.” According to the product box, this unit wouldn’t have a 115 V/230 V switch, which is present, as you can see in Figure 2.

Figure 1: Product box, listing features the power supply doesn’t have

Figure 2: TiVECO TVPS450 power supply

Figure 3: TiVECO TVPS450 power supply

Now, to make things worse, the 115 V/230 V switch is located in the wrong place. This is the first time we’ve seen a manufacturer putting this switch on the front side of the power supply. To change the position of this switch, you will have to open your computer. It is just a matter of common sense that this switch must be located on the rear side of the power supply, so you can access it even with the computer closed. We speculate that the manufacturer wanted to deceive consumers. Most users nowadays know that if there is no 115 V/230 V switch on the back of the power supply, then the unit probably has auto voltage selection and an active PFC circuit. Since on this power supply you won’t find the switch in its usual place, consumers can wrongly assume that this unit has these features, which is not the case.

The TiVECO TVPS450 is 5.5” (140 mm) deep, using a 120 mm sleeve bearing fan on its bottom (model 12025BN from an unknown manufacturer).

This unit doesn’t have a modular cabling system. Only the main motherboard cable is protected with nylon sleeve, which comes from inside the unit. This power supply comes with the following cables:

• Main motherboard cable with a 20/24-pin connector, 13.4” (34 cm) long
• One cable with one ATX12V connector, 13.4” (34 cm) long
• One cable with two SATA power connectors, 12.6” (32 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two standard peripheral power connectors, 13.4” (34 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two standard peripheral power connectors and one floppy disk drive power connector, 13.4” (34 cm) to the first connector, 5.9” (15 cm) between connectors

Only the wires on the main motherboard cable are 18 AWG, which is the minimum recommended gauge. All other wires are 20 AWG, i.e., thinner than the minimum recommended gauge.

The cable configuration is bad, as all the cables are too short; there are only two SATA power connectors, which are too close to each other (you will have a hard time trying to install an optical drive and a hard disk drive that use this kind of connector in your system); and there is no power connector for video cards.

Figure 4: Cables

Let’s now take an in-depth look inside this power supply.

[nextpage title=”A Look Inside the TiVECO TVPS450″]

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.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

Figure 5: Top view

Figure 6: Front quarter view

Figure 7: Rear quarter view

Figure 8: The printed circuit board

[nextpage title=”Transient Filtering Stage”]

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 of the TiVECO TVPS450 has only one ferrite coil and two Y capacitors. Keep in mind that this stage not only prevents electrical noise and spikes from entering the power supply, but also prevents electromagnetic noise generated by the power supply from entering the power grid and interfering with other electronic equipment you might have in your home.

Figure 9: Transient filtering stage

On the next page, we will have a more detailed discussion about the components used in the TiVECO TVPS450.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of the T
iVECO TVPS450. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one KBL406G rectifying bridge, which is not attached to a heatsink. This bridge supports up to 4 A at 50° C, so in theory, you would be able to pull up to 460 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 368 W without burning itself out. Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply. Here we can clearly see that it is impossible for this power supply to be a 450 W product.

Figure 10: Rectifying bridge

This power supply doesn’t have a PFC circuit. The electrolytic capacitors from the voltage doubler circuit are from a company called Jay’Long and labeled at 105° C.

In the switching section, one 2SK3797 MOSFET is employed using the single-transistor forward configuration. This transistor supports up to 13 A at 25° C or 52 A at 25° C in pulse mode. (Unfortunately, the manufacturer doesn’t state the current limit at 100° C.) This transistor presents a 320 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number is, the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

Figure 11: The main switching transistor and the +5VSB switching transistor

The primary is managed by a UC3842 PWM controller.

Figure 12: PWM controller

Let’s now take a look at the secondary of this power supply.

[nextpage title=”Secondary Analysis”]

The TiVECO TVPS450 uses a regular design in its secondary, with Schottky rectifiers.

The maximum theoretical current each 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. As an exercise, we can assume a duty cycle of 30 percent.

The +12 V output uses one GMR30H60C Schottky rectifier (30 A, 15 A per internal diode at 25° C, 0.75 V maximum voltage drop), which gives us a maximum theoretical current of 21 A or 257 W for this output.

The +5 V output uses one PBYR3045WT Schottky rectifier (30 A, 15 A per internal diode at 124° C, 0.76 V maximum voltage drop), which gives us a maximum theoretical current of 21 A or 107 W for this output.

The +3.3 V output uses one S16C40C Schottky rectifier (16 A, 8 A per internal diode at 100° C, 0.70 V maximum voltage drop), which gives us a maximum theoretical current of 11 A or 38 W for this output.

Figure 13: The +12 V, +5 V, and +3.3 V rectifiers

This power supply uses an LP-7510 monitoring integrated circuit, which supports only over voltage (OVP) and under voltage (UVP) protections.

Figure 14: Monitoring circuit

The electrolytic capacitors that filter the outputs are also from Cheng and are labeled at 105° C, as usual.

[nextpage title=”Power Distribution”]

Figure 15 shows the power supply label containing all the power specs.

Figure 15: Power supply label

This power supply has a single +12 V rail configuration, so there is not much to talk about here.

How much power can this unit really deliver? Let’s find out.

[nextpage title=”Load Tests”]

We conducted several tests with this power supply, as described in the article, “Hardware Secrets Power Supply Test Methodology.” 

Because we had no clue as to the real wattage of this power supply, we tested it differently. Starting from 85 W, we increased the load little by little until we could see the maximum amount of power we could extract from the reviewed unit.

 If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (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. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, both inputs were connected to the power supply’s single +12 V rail.

Input	Test 1	Test 2	Test 3	Test 4	Test 5	Test 6
+12VA	3 A (36 W)	3.5 A (42 W)	4.5 A (54 W)	5.5 A (66 W)	6.25 A (75 W)	7.5 A (90 W)
+12VB	2.5 A (30 W)	3.25 A (39 W)	4 A (48 W)	5 A (60 W)	6 A (72 W)	7 A (84 W)
+5 V	1 A (5 W)	1 A (5 W)	1.5 A (7.5 A)	1.5 A (7.5 A)	2 A (10 W)	2 A (10 W)
+3.3 V	1 A (5 W)	1 A (5 W)	1.5 A (4.95 W)	1.5 A (4.95 W)	2 A (6.6 W)	2 A (6.6 W)
+5VSB	1 A (5 W)	1 A (5 W)	1 A (5 W)	1 A (5 W)	1 A (5 W)	1 A (5 W)
-12 V	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)	0.5 A (6 W)
Tot al	85.1 W	99.7 W	125.2 W	148.3 W	173.0 W	198.9 W
% Max Load	18.9%	22.2%	27.8%	33.0%	38.4%	44.2%
Room Temp.	40.5° C	40.4° C	41.1° C	41.1° C	41.2° C	41.4° C
PSU Temp.	40.4° C	40.1° C	40.2° C	40.4° C	40.6° C	40.8° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass	Pass
AC Power	119.4 W	130.4 W	161.4 W	191.5 W	224.3 W	260.4 W
Efficiency	73.9%	75.3%	76.7%	77.4%	77.6%	77.5%
AC Voltage	117.9 V	117.8 V	117.3 V	117.2 V	116.7 V	116.5 V
Power Factor	0.633	0.641	0.648	0.653	0.654	0.654
Final Result	Pass	Pass	Pass	Pass	Pass	Pass

Input	Test 7	Test 8	Test 9	Test 10	Test 11
+12VA	8.25 A (99 W)	9.25 A (111 W)	10 A (120 W)	11 A (132 W)	12 A (144 W)
+12VB	8 A (96 W)	9 A (108 W)	10 A (120 W)	11 A (132 W)	11.75 A (141 W)
+5 V	2.5 A (12.5 W)	2.5 A (12.5 W)	3 A (15 W)	3 A (15 W)	3.5 A (17.5 W)
+3.3 V	2.5 A (8.25 W)	2.5 A (8.25 W)	3 A (9.9 W)	3 A (9.9 W)	3.5 A (11.55 W)
+5VSB	1 A (5 W)	1 A (5 W)	1 A (5 W)	1 A (5 W)	1 A (5 W)
-12 V	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)
Total	222.4 W	244.8 W	267.8 W	287.3 W	309.9 W
% Max Load	49.4%	54.4%	59.5%	63.8%	68.9%
Room Temp.	42.2° C	42.6° C	44.4° C	45.3° C	46.6° C
PSU Temp.	41.2° C	41.9° C	43.1° C	43.9° C	45.3° C
Voltage Regulation	Pass	Pass	Pass	Pass	Fail on +12VB
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	288.6 W	319.2 W	353.1 W	384.9 W	421.1 W
Efficiency	77.1%	76.7%	75.8%	74.6%	73.6%
AC Voltage	116.2 V	115.4 V	115.5 V	115.0 V	114.7 V
Power Factor	0.657	0.658	0.66	0.661	0.662
Final Result	Pass	Pass	Pass	Pass	Fail

As we suspected, the TiVECO TVPS450 can’t deliver its labeled wattage. This power supply burned during what would be our test number 12. The switching transistor was the component that burned.

Efficiency was always below 80%, between 73.6 and 77.6 percent. Keep in mind that the manufacturer promises 80% minimum efficiency, which is a lie. See Figure 1.

Voltage regulation was not bad for a product in this class. Until test seven, all outputs were within three percent of their nominal values, except the -12 V output, which was still inside the proper range. In the table below, we show which outputs were outside the tighter 3% range we like to see in order to consider a power supply “flawless.” The outputs that were within three percent of their nominal values were labeled “≤ 3%.” Only during test 11 the voltage at the +12VB input of our load tester was outside the allowed range. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Input	Test 8	Test 9	Test 10	Test 11
+12VA	≤ 3%	+11.61 V	+11.51 V	+11.43 V
+12VB	+11.61 V	+11.53 V	+11.40 V	+11.32 V
+5 V	≤ 3%	≤ 3%	≤ 3%	≤ 3%
+3.3 V	≤ 3%	≤ 3%	≤ 3%	≤ 3%
+5VSB	≤ 3%	≤ 3%	≤ 3%	≤ 3%
-12 V	-11.53 V	-11.61 V	-11.60 V	-11.62 V

Let’s discuss the ripple and noise levels on the next page.

[nextpage title=”Ripple and Noise Tests”]

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The TiVECO TVPS450 provided ripple and noise levels below the maximum allowed during all tests, as you can see in the table below.

Input	Test 1	Test 2	Test 3	Test 4	Test 5	Test 6
+12VA	52.2 mV	56.2 mV	38.4 mV	42.2 mV	41.0 mV	41.8 mV
+12VB	53.8 mV	54.4 mV	40.0 mV	41.8 mV	40.8 mV	41.8 mV
+5 V	33.4 mV	32.8 mV	34.6 mV	35.6 mV	36.4 mV	38.8 mV
+3.3 V	15.2 mV	15.2 mV	16.6 mV	17.4 mV	18.4 mV	18.2 mV
+5VSB	12.2 mV	11.6 mV	12.2 mV	13.4 mV	12.3 mV	13.4 mV
-12 V	82.2 mV	86.6 mV	65.2 mV	72.4 mV	68.4 mV	79.4 mV

Input	Test 7	Test 8	Test 9	Test 10	Test 11
+12VA	43.8 mV	47.6 mV	45.4 mV	45.8 mV	51.6 mV
+12VB	42.4 mV	45.4 mV	44.4 mV	43.3 mV	60.4 mV
+5 V	39.4 mV	39.2 mV	39.6 mV	39.4 mV	43.4 mV
+3.3 V	20.4 mV	20.4 mV	21.4 mV	21.0 mV	21.4 mV
+5VSB	13.4 mV	14.4 mV	13.8 mV	12.8 mV	14.4 mV
-12 V	87.4 mV	95.2 mV	96.8 mV	105.8 mV	116.4 mV

Below you can see the waveforms of the outputs during test 11.

Figure 16: +12VA input from load tester during test 11 at 309.9 W (51.6 mV)

Figure 17: +12VB input from load tester during test 11 at 309.9 W (60.4 mV)

Figure 18: +5V rail during test 11 at 309.9 W (43.4 mV)

Figure 19: +3.3 V rail during test 11 at 309.9 W (21.4 mV)

[nextpage title=”Main Specifications”]

The main specifications for the TiVECO TVPS450 power supply include:

• Standards: NA
• Nominal labeled power: 450 W at 50° C
• Measured maximum power: 309.9 W at 46.6° C
• Labeled efficiency: 80% minimum during all loads
• Measured efficiency: Between 73.6% and 77.6%, at 115 V (nominal, see complete results for actual voltage)
• Active PFC: No
• Modular Cabling System: No
• Motherboard Power Connectors: One 20/24-pin connector and one ATX12V connector
• Video Card Power Connectors: None
• SATA Power Connectors: Two on one cable
• Peripheral Power Connectors: Four on two cables
• Floppy Disk Drive Power Connectors: One
• Protections (as listed by the manufacturer): Over voltage (OVP), under voltage (UVP), over current (OCP), over power (OPP), and short-circuit (SCP) protections
• Are the above protections really available? This unit does not have over current (OCP) and over power (OPP) protections, but the others are present.
• Warranty: NA
• More Information: https://tiveco.co
• Average Price in the US*: USD 20.00

* Researched at Google Shopping on the day we published this review.

[nextpage title=”Conclusions”]

We think it is amazing how there are still manufacturers selling power supplies that can’t deliver their labeled wattage. And the worst part is their lying about it. Let’s analyze the features as listed by the manufacturer on the product box (refer to Figure 1):

• “Guaranteed to deliver rated specifications at 50° C.” A lie. We could only pull up to 310 W from this power supply.
• “80%+ energy efficiency at 20%, 50% and 100% load condition for less heat generation and lower energy bill.” Another lie. Efficiency was between 74.6% and 77.6% during our tests (not to mention that this unit can’t deliver 100% load).
• “Supports the latest ATX12V v2.2 and EPS12V 2.91 standards and is backwards (sic) compatible with ATX12V 2.01 systems.” One more lie. This power supply can’t be compatible with the EPS12V standard, as it doesn’t even have an EPS12V connector.
• “Powerful +5Vsb rail with 3A rating.” We couldn’t test this one, as we pulled 1 A from the +5VSB output during all our tests.
• “Auto switching circuitry provide (sic) universal AC input 90 ~ 264 V.” Again, a lie. This power supply doesn’t have this feature.
• “Over Current/Voltage/Power Protection, Under Voltage Protection, and Short Circuit Protection provide maximum safety for your critical system components.” Yet another lie. This power supply does not support over current (OCP) and over power (OPP) protections.

Well, at least compared to other low-end power supplies, noise and ripple levels were always inside the proper range, and voltage regulation only went outside the specifications during our last test, with the power supply delivering 310 W.