LEPA B650 Power Supply Review

[nextpage title=”Introduction”]

The new “B” series from LEPA carries the 80 Plus Bronze certification and is available in 450 W, 550 W, 650 W, 700 W, 750 W, 800 W, and 850 W versions. Let’s take an in-depth look at the 650 W version, which costs only USD 80.

LEPA is a brand that belongs to Enermax’s distributor, Ecomaster. The manufacturer behind the “B” series is CWT, utilizing the same platform used in the Enermax NAXN 80+, the Enermax NAXN 82+, and the Corsair CX series. (Even though Enermax has its own factories, some of its power supplies are manufactured by others.)

Figure 1: LEPA B650 power supply

Figure 2: LEPA B650 power supply

The LEPA B650 is 5.5” (140 mm) deep, using a 120 mm sleeve bearing fan on its bottom (Yate Loon D12SH-12).

The reviewed power supply doesn’t have a modular cabling system. All cables are protected with nylon sleeves that come from inside the unit. This power supply comes with the following cables:

• Main motherboard cable with a 20/24-pin connector, 20.5” (52 cm) long
• One cable with two ATX12V connectors that together form an EPS12V connector, 24.4” (62 cm) long
• Two cables, each with one six/eight-pin connector for video cards, 20.1” (51 cm) long
• One cable with four SATA power connectors, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with three SATA power connectors and one standard peripheral power connector, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with three standard peripheral power connectors and one floppy disk drive power connector, 18.1” (46 cm) to the first connector, 5.9” (15 cm) between connectors

All wires are 18 AWG, which is the minimum recommended gauge. The number of connectors is adequate for a 650 W power supply.

Figure 3: Cables

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

[nextpage title=”A Look Inside the LEPA B650″]

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 4: Top view

Figure 5: Front quarter view

Figure 6: Rear quarter view

Figure 7: 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. 

In the transient filtering stage, this power supply is flawless, with one X capacitor and two Y capacitors more than the minimum required.

Figure 8: Transient filtering stage (part 1)

Figure 9: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the LEPA B650.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of the LEPA B650. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one GBU1506 rectifying bridge, which is attached to a heatsink connected to the heatsink of the active PFC transistors. This bridge supports up to 15 A at 100° C. So, in theory, you would be able to pull up to 1,725 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 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.

Figure 10: Rectifying bridge

The active PFC circuit uses two FCPF20N60 MOSFETs, each supporting up to 20 A at 25° C or 12.5 A at 100° C in continuous mode
(see the difference temperature makes) or 60 A at 25° C in pulse mode. These transistors typically present a 150 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

Figure 11: Active PFC transistors and diode

The output of the active PFC circuit is filtered by one 330 µF x 400 V Japanese electrolytic capacitor, from Rubycon, labeled at 85° C.

In the switching section, another two FCPF20N60 MOSFETs are employed using the traditional two-transistor forward configuration. The specifications for these transistors were already discussed above.

Figure 12: Switching transistors

The primary is managed by the famous CM6800 active PFC/PWM combo controller.

Figure 13: Active PFC/PWM combo controller

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

[nextpage title=”Secondary Analysis”]

The LEPA B650 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 four SBR40U60CT Schottky rectifiers (40 A, 20 A per internal diode at 25° C, 0.60 V maximum voltage drop). This gives us a maximum theoretical current of 114 A or 1,371 W for the +12 V output.

The +5 V output uses two SBR30U30CT Schottky rectifiers (30 A, 15 A per internal diode at 150° C, 0.54 V maximum voltage drop). This gives us a maximum theoretical current of 43 A or 214 W for the +5 V output.

The +3.3 V output uses one VS-40CPQ060 Schottky rectifier (40 A, 20 A per internal diode at 120° C, 0.68 V maximum voltage drop). This gives us a maximum theoretical current of 29 A or 94 W for the +3.3 V output.

Figure 14: The +12 V, +5 V, and +3.3 V rectifiers

This power supply uses an ST9S429 monitoring integrated circuit, which apparently is a rebranded S3515. This chip supports over voltage (OVP), under voltage (UVP), and over current (OCP) protections. Even though this chip provides two +12 V over current channels, the manufacturer decided to configure this unit as a single-channel model.

Figure 15: Monitoring circuit

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

[nextpage title=”Power Distribution”]

In Figure 16, you can see the power supply label containing all the power specs.

Figure 16: Power supply label

As you can see, this unit has a single +12 V rail, 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.” 

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 the behavior of the reviewed unit 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 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. (The power supply’s EPS12V connector was installed on the +12VB input of the load tester.)

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	5 A (60 W)	10 A (120 W)	14.5 A (174 W)	19 A (228 W)	24.5 A (294 W)
+12VB	5 A (60 W)	10 A (120 W)	14 A (168 W)	19 A (228 W)	24 A (288 W)
+5 V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)	3 A (15 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	136.1 W	263.2 W	380.5 W	507.3 W	644.9 W
% Max Load	20.9%	40.5%	58.5%	78.0%	99.2%
Room Temp.	46.5° C	45.7° C	48.5° C	49.4° C	48.8° C
PSU Temp.	45.8° C	46.7° C	47.7° C	49.3° C	50.3° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	158.8 W	302.4 W	442.1 W	601.4 W	787.0 W
Efficiency	85.7%	87.0%	86.1%	84.4%	81.9%
AC Volt age	115.4 V	113.3 V	111.7 V	110.5 V	109.9 V
Power Factor	0.982	0.993	0.996	0.997	0.998
Final Result	Pass	Pass	Pass	Pass	Pass

In our tests, the LEPA B650 presented efficiency between 81.9% and 87.0%, matching the 80 Plus Bronze certification, which promises a minimum efficiency of 82% at light (i.e., 20%) and full loads, and 85% at typical (i.e., 50%) load.

All voltages were closer to their nominal values during all tests. 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. However, we’d prefer to see voltages within 3% of their nominal values to consider this unit “flawless,” which didn’t happen. See the table below.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	≤ 3%	≤ 3%	+11.63 V	+11.55 V	+11.49 V
+12VB	≤ 3%	≤ 3%	+11.63 V	+11.56 V	+11.50 V
+5 V	+5.18 V	+5.17 V	≤ 3%	≤ 3%	≤ 3%
+3.3 V	≤ 3%	≤ 3%	≤ 3%	≤ 3%	≤ 3%
+5VSB	≤ 3%	≤ 3%	≤ 3%	≤ 3%	≤ 3%
-12 V	-11.29 V	-11.38 V	-11.47 V	-11.53 V	-11.60 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 LEPA B650 provided ripple and noise levels inside the specification. See the table below.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	13.2 mV	14.2 mV	19.6 mV	43.6 mV	70.6 mV
+12VB	13.6 mV	14.0 mV	20.0 mV	43.6 mV	70.2 mV
+5 V	11.2 mV	12.2 mV	13.4 mV	16.0 mV	20.2 mV
+3.3 V	11.2 mV	12.6 mV	15.2 mV	17.8 mV	20.6 mV
+5VSB	19.4 mV	20.6 mV	23.2 mV	26.4 mV	30.6 mV
-12 V	32.2 mV	34.2 mV	37.8 mV	41.2 mV	47.4 mV

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

Figure 17: +12VA input from load tester during test five at 644.9 W (70.6 mV)

Figure 18: +12VB input from load tester during test five at 644.9 W (70.2 mV)

Figure 19: +5V rail during test five at 644.9 W (20.2 mV)

Figure 20: +3.3 V rail during test five at 644.9 W (20.6 mV)

[nextpage title=”Overload Tests”]

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit failed this test, at it burned when we tried to pull more than described below.

Input	Overload Test
+12VA	29 A (348 W)
+12VB	29 A (348 W)
+5 V	10 A (50 W)
+3.3 V	8 A (26.4 W)
+5VSB	3 A (15 W)
-12 V	0.5 A (6 W)
Total	756.7 W
% Max Load	116.4%
Room Temp.	47.8° C
PSU Temp.	52.8° C
AC Power	961.0 W
Efficiency	78.7%
AC Voltage	107.4 V
Power Factor	0.998

[nextpage title=”Main Specifications”]

The main specifications for the LEPA B650 power supply include:

• Standards: ATX12V 2.31 and EPS12V 2.92
• Nominal labeled power: 650 W
• Measured maximum power: 756.7 W at 47.8° C
• Labeled efficiency: Up to 88%, 80 Plus Bronze certification, 82% minimum at light (i.e., 20%) and full loads, and 85% minimum at typical (i.e., 50%) load
• Measured efficiency: Between 81.9% and 87.0%, at 115 V (nominal, see complete results for actual voltage)
• Active PFC: Yes
• Modular Cabling System: No
• Motherboard Power Connectors: One 20/24-pin connector and two ATX12V connectors that together form an EPS12V connector
• Video Card Power Connectors: Two six/eight-pin connectors on separate cables
• SATA Power Connectors: Seven on two cables
• Peripheral Power Connectors: Four on two cables
• Floppy Disk Drive Power Connectors: One
• Protections (as listed by the manufacturer): Over voltage (OVP), over current (OCP), over power (OPP), brown out, and short-circuit (SCP)
• Are the above protections really available? Over power protection (OPP) failed. This unit also has under voltage protection (UVP).
• Warranty: Three years
• More Information: https://www.lepatek.com
• Average Price in the U.S.*: USD 80.00

* Researched at Newegg.com on the day we published this review.

[nextpage title=”Conclusions”]

The LEPA B650 is a fair power supply, with efficiency between 82% and 87%, voltages within the allowed range, and noise and ripple levels below the maximum allowed. The only negative was the fact that it burned when we overloaded it, at 750 W.

Although not a flawless unit, the LEPA B650 is a good mainstream power supply, especially for its price (USD 80). One of its main competitors is the Rosewill HIVE 650 W, which costs USD 5 more. The model from LEPA presented higher maximum efficiency in our tests, while the model from Rosewill presented hi
gher minimum efficiency, better voltage regulation, lower noise and ripple levels, and it didn’t fail our overload test.

On one hand, if you want a better power supply, you will have to pay more. On the other hand, 650 W power supplies cheaper than USD 80 have lower efficiency and, in some cases, fake labeled wattages. The decision is yours.