DPX6012S or a newcomer among adjustable power supply boards

I already have quite a few reviews of different boards that can be used to build an adjustable power supply, often called a “laboratory” power supply. So I simply couldn’t pass up a new arrival in this market: the DPXxxxx series of boards. A few of my readers had also asked me to review it.
Well, the board has arrived and it works, but am I happy with it? Read on for my thoughts on the board and my conclusions.


I’ll start with the price. While searching, I found this board from various sellers, and some even offered free shipping to the forwarding service. I chose the best-priced option (not counting the forwarding service’s fees), but I placed the order about a couple of months ago, so things may have changed since then.


This kit is most similar to the ZXYxxxx series boards, at least in its labeling and output voltage range. There are 6 boards in the series:
DPX3203 (DPX3203S) - 32 V, 3 A
DPX6005 (DPX6005S) - 60 V, 5 A
DPX6012 (DPX6012S) - 60 V, 12 A
The S suffix means it can be connected to a computer, just like the ZXY boards.

The DPX6012S is the most powerful and feature-packed board in the series. The other boards are a little simpler and share the same design.
1. Overall view of the DPX3203 module
2. DPX6005, rear view
3. DPX3203, rear view
4. DPX6012 power section


But when it comes to the claimed specifications, things are all over the place. The image above shows 35 V/3 A on the DPX3203’s display, while the listed specifications say 0–32 V. The DPX6005 is rated for a maximum of 60 V, while the DPX6012 is rated for 62 V. On top of that, the board names are mixed up in the heading, and they’re mixed up in the English-language datasheet too; the Chinese version is fine. I’ll come back to all this, though, because the discrepancies don’t end there.


And here are the specifications in Russian.
Model: DPX6012/DPX6012S (with communication port)
Input voltage: 6 V–75 V
Output voltage adjustment range: 0–62 V (input voltage must be higher than output voltage)
Output current adjustment range: 0–12 A
Input protection: reverse-polarity protection
Output protection: (0vp) voltage limit, (0cp) current limit, (0pp) power limit
Output power: 0–744 W
Output voltage setting resolution: 10 mV
Output current setting resolution: 10 mA
Output ripple: <200 mVpp (input 48 V, output 24 V, current 5 A)
Ripple factor at 100 Hz: <1/10000
Output voltage/current display resolution: 10 mV, 10 mA
Voltage measurement error: ±1%+20 mV
Current measurement error: ±2%+20 mA
Response time: 1.5 A or output power >50 W
Operating temperature: 0–60 °C
Storage temperature: -20 °C–70 °C
Application: indoor use, maximum humidity 80%
Weight: 258 g


Although I ordered the kit through a forwarding service, they shipped it in the same box the seller had sent it in, so it ended up with double packaging: the seller’s and the forwarder’s. It’s certainly secure, but it adds to the total weight I have to pay for. At least the smiley on the box cheered me up :)


The kit includes the converter itself and a USB cable for connecting it to a computer. The cable turned out to be decent and is 1.5 meters long, but it has standard USB-A connectors at both ends, so it’s not very useful for everyday use.


The converter consists of two boards: a control board and a power board.


The front panel has a 1.8-inch display, an encoder, and six buttons. The panel itself is made of about 3 mm-thick acrylic, with a protective film stuck to it. I haven’t removed the film yet, since I still need to install the whole assembly in an enclosure. But I can already say that, in my opinion, it’s not very convenient: mounting it on the front panel looks ugly, and putting it behind the front panel is even worse.


On the back is the control board, with the display connector.


The converter is controlled by the familiar STM8S005 microcontroller. There’s also an op-amp on the board, presumably in the DAC circuit, but I can’t say for sure.


The computer interface board is installed separately and has optical isolation. Overall, the design is quite sophisticated. You can use it “as is” or mount it separately on wires.
The encoder is not push-button type, has 24 steps per revolution, and is quite slim, so common replacements may not fit.


The power section is quite compact for the rated output, although the DPS5020 is even more compact: at the same dimensions, its power is almost one and a half times higher. The cable connecting it to the control module is short, about 12 cm, so there isn't much room to maneuver inside the enclosure.


A closer look at the board. The assembly is neat—not perfect, of course, but pretty good.


Cooling is active, using a 40 mm fan. The heatsink has a rather interesting design. I wouldn't mind buying some of these heatsinks on their own, without the converter board attached; with the board, they end up being too expensive. :)


1. The input has a pair of 470 µF capacitors rated for 100 V. I also like the fuse design: it's replaceable and rated for 15 A. Too bad fuses like this aren't rated for high voltage.
2. The converter's switching transistor is an N-channel IPP045N10N3, rated for 100 V and 100 A, with an on-resistance of 4.2 mΩ.
3. The power components are mounted symmetrically on both sides of the heatsink.
4. The output has an MBR20100 diode assembly and an inductor with a core diameter of 32–33 mm. The output inductor is held only by its leads, with no additional mounting.


There are two 1000 µF, 63 V capacitors at the output. I think it would be better to use 100 V capacitors, like the ones on the input, and reduce the capacitance to 470–680 µF. You can also see a Dale current-sense shunt here, measuring 4.7 mΩ; it doesn't get particularly hot during operation.
One nice detail: all the large electrolytic capacitors are bypassed with small 0.1 µF, 100 V capacitors.


Power regulators, converters, op-amps—in short, everything except the control section.


1. The input power goes to an XL7015E1 DC-DC converter. The manufacturer specifies a maximum input voltage of 80 V, which gives plenty of headroom. Still, after I burned out the input regulator on the ZXY6005 board, I try not to take chances and modify this section.
2. There's a linear regulator nearby, presumably to power the control board.
3. I also found another converter nearby, based on a 34063 PWM controller. At first I thought the transformer on the board was there to drive the MOSFET, but it turns out it's used to generate a separate, galvanically isolated supply.
4. The optocoupler and TL431 shunt regulator also support this theory.
5. There's a third PWM controller on the board as well, an XL1509. This one controls the main converter's power transistor. The ZXY6005 board used the same circuit design. Apparently, the manufacturer decided not to reinvent the wheel and stuck with a proven approach.
6. There's some other small componentry under the heatsink; its purpose is unknown.


The op-amp section for current and voltage control. In fact, it uses the same approach as the ZXY6005. If I remember correctly, even the op-amps are the same. I also think there's an option here to connect a “hardware” indicator for CC/CV modes.


For a while, I thought the N-channel MOSFET and the galvanically isolated converter were simply there to power a basic driver, but the reality turned out to be much more impressive.
I happened to spot the driver under the fan, and I can say that it's a clear step up from the ZXY6005. That one had a P-channel transistor with a rather silly control circuit. The DPS series converters use a simple high-side driver. Here, the manufacturer has installed a low-side driver, the TC1413, controlled by a fast HCPL0600 optocoupler, which is in turn controlled by the PWM controller.
It's a rather brute-force solution, of course, but a driver capable of 3 A and a fast optocoupler with a digital output are genuinely good choices. Another advantage is that even if the power section fails, the measurement and control sections won't be affected! If only they'd put the shunt in the positive rail instead of the ground side, this would be perfect. :(


The underside is bare; the power traces have been reinforced with a layer of solder.



First power-up: nothing exploded or burned out. At startup, nothing interesting appears on the screen; the board simply enters operating mode without any splash screens.
The screen itself is nothing special. I’d guess it came from some mobile phone, since its viewing angle is odd for this device: the image is clear from the front, right, above and below, but quickly inverts when viewed from the left. If you position the screen vertically with the ribbon cable at the bottom, the image inverts when viewed from above, which is what made me think it came from a mobile phone.


The screen is more like the ones used in the DPH/DPS series converters. The ZXY series models had a standard 1602 display. The screen shows:
1, 2. When the output is off, the current voltage/current/power are shown in yellow. The left/right buttons select the adjustment step, and the set button selects what to adjust (current/voltage); the encoder is used to make the adjustment.
3. The ML button controls memory; the left/right buttons are used to save settings to memory.
4, 5. Pressing Out activates operating mode. The screen then shows the CCCV operating mode, along with the current and voltage readings and power. Below that are the Ah counter and a timer showing the time since power was applied. Unlike the ZXY, the counters reset to zero when the power is turned off. I found this out by accident while looking for a reset button, as on the ZXY. In my opinion, this is a poor design; sometimes it’s better when the converter remembers these values.
6. There’s also a Shift button. Pressing it displays the corresponding label on the screen; pressing Set switches the panel to settings mode.
7. Settings mode has two screens. The first lets you set the voltage, current and power protection thresholds.
8. The second screen is supposed to let you set the temperature, address and port speed, but only the port selection works.
9, 10, 11. The protection is trigger-based: if a set threshold is exceeded, the converter shuts down and displays the corresponding message.
12. The specifications claimed a maximum of 62 V or 744 W, but in reality the converter can output 60 V, 12.1 A or 720 W.


Image from the manual, with my description in Russian.
1. Output voltage
2. Output current
3. Output power
4. Capacity delivered, in Ah; resolution: 1 mAh
5. Time since the converter was switched on.
6. Active memory slot
7. Set current
8. Set voltage
9. Indicates that a setting is being saved to memory, or that Shift mode is active.
A. Indicates CC/CV operating mode or a protection trip
B. Output status indicator
C. Board model information. This shows what the board can output. At first I thought it showed the maximum current/voltage set in the settings, but no—it just displays fixed values.

The converter is easy to operate, but two things spoil the overall picture:
1. Power limiting is trigger-based only
2. The Ah counter resets when the power is turned off.



The first test checks calibration accuracy.

First, I checked the accuracy of voltage setting and measurement. I set the voltage to the following values in order: 0.05, 0.1, 0.2, 0.5, 1.0, 2.0, 3.3, 4.2, 5.0, 8.4, 12.0, 20.0, 30.0, 40.0, 50.0 and 60.0 V. The photo shows that the actual output voltage is slightly higher than the set value in almost every case; it only gets close to the target at the very top of the range.
The voltage measured by the converter itself jumps around, sometimes high and sometimes low. More precisely, below 20 V it reads lower than the actual voltage, and above 20 V it reads higher.


The current readings are even worse. I tested 10, 50, 100, 200, 300 and 600 mA, as well as 1, 2, 5, 7.5, 10 and 12.1 A.
Up to 2 A, the actual current is higher than the set value; above that, it’s lower. Worse still, the converter’s own readings are exactly the opposite: below 2 A, it reads lower than the actual current; above that, it reads higher.


I also tested how the output voltage depends on the load. The test was run at four “standard” voltages—3.3, 5.0, 12.0 and 19.0 V—with no load, and at currents of 6 A and 12 A.

In all the tests, the voltage stays stable at 50% load, but at 12 A it is noticeably higher than the set value.


While I was at it, I ran a couple more quick tests.
1. I ran it for a while at one-third of maximum output power, but at maximum current.
2. I figured out when and how the fan turns on.

The fan switches on in steps; there’s no speed control, and it’s noticeably noisy. It has two turn-on thresholds: either the current exceeds 3 A (it turns on at 3.01 A), or the power exceeds 30 W.


The heat is concentrated in three components:
1. Output inductor: 73 °C at 12 A.
2. Input transistor: 60 °C at one-third load.
3. With an input voltage of 60 V, the input voltage regulator reaches roughly the same temperature as the transistor, around 55–60 degrees.


The specs stated that the total ripple amplitude was up to 200 mVpp (48 V input, 24 V output, 5 A current), so I used a 48 V power supply, set the converter output to 24 V, and loaded it to 5 A. But then I hit a snag. The oscilloscope showed broadband noise, even with the bandwidth limit enabled.


At first I suspected ground loops and the like, but it turned out the ripple was there even with the input shorted.


Anyway, I’ll look into what’s going on, and for now I’ll get out the instrument I’m more used to. As they say, an old horse doesn’t spoil the furrow.
So, here’s what we have:
1, 2. 24 V at 5 and 10 A
3, 4. 5 V at 6 and 12 A
5, 6. 12 V at 6 and 12 A.

Well, it does fit within the claimed 200 mV peak-to-peak, but it’s still rather noisy.


The power supply couldn’t handle any more, so I connected a more powerful source and continued testing.


1, 2. 36 V at 6 and 12 A
3, 4. 48 V at 6 and 12 A.

The worst case is at around 36 V and maximum current; after that, the ripple starts to decrease.


And since I’d already got the powerful power supply out, I decided to measure efficiency and temperature at higher power as well. In this case, the board was loaded to about 2/3 of its maximum (40 V, 12 A). I can’t go any higher for now because I don’t have enough load capacity for extended operation.


After about 20 minutes, I measured the temperatures. The output inductor was still at 70 degrees, but the power transistor had heated up to over 100. That’s a bit much :(


Efficiency measurement; the input voltage was 62 V. The measurement is of course rough, since it was taken using the power supply and converter’s own meters, but it gives you a general idea.



Next was supposed to be a test of the software. It was meant to look like the screenshot below, but it turned out there was simply nowhere to download it. Well, there is a link to a Chinese Baidu page, but I can’t download it from there. If anyone manages to, I’d be very grateful. It has software for the 6005 and 6012 boards, about 450 MB in total.
By the way, I later noticed that in every screenshot of this software I found online, it’s inactive, so there’s no indication of what it looks like when running.


Thanks to the readers’ help, I was able not only to download the software, but also to figure it out. Thank you!
First, it turned out to be software for the DKP6012 board. The package also includes software for the 6005 version. They’re interchangeable, but with the latter you can’t set the current above 5 A.


Since downloading the software can be a bit tricky, I’ve uploaded it to Google Drive. The documentation, protocol description, and several different software versions are there too.

The software installer will be in Chinese. It’s not too hard to figure out what to click, but at the end it asks what to do next and shows three buttons: restart, shut down, or cancel. To help you tell which is which, I’ve included a screenshot of the same window in English so you don’t accidentally shut down your computer.
If you have trouble launching the software, go to the folder where it was installed and rename the exe file so its name doesn’t contain Chinese characters, for example, to DPX6012.


The software is extremely simple. For it to connect to the converter, the converter’s address (in its settings) must be 000.
Then just select the COM port in the software. You can find its address in Device Manager; mine is COM11. Then click Connect.
There’s no real-time adjustment. To change the current or voltage, you have to either turn the virtual knob or enter a value above it; the new value is applied by clicking the button with the green arrow. The software also plots voltage/current, but it does so extremely slowly. Overall, it’s a lot like the ZXY software—just as primitive.


I also launched another version along the way. It’s a little different, but the program is in Chinese, so I get gibberish instead of letters.



I’m planning to put all this into an enclosure, and while checking the fit, I found that the enclosures I recently bought—and even made a video about—are practically a perfect fit. The converter board and power supply fit inside perfectly, with room left over for an exhaust fan, terminals, and other bits and pieces.
The board in the photo is exactly the same size as a standard computer power supply board. We used to manufacture UPS units, so we had some ready-made charger boards left over.


For comparison, here's a photo with a standard computer PSU board. It's best to shift the control board to the right, as shown here, to leave more room for the terminals.


One small bonus turned up during the build: if you want, you can screw the converter board to the rear panel (or any flat panel, really), so the fan works as an exhaust fan. Very convenient.


Now for the conclusions. First, my overall impression:
The circuitry and construction are reasonably well done.
Calibration accuracy is average; personally, I'd like it to be better.
Functionality is limited. I couldn't find any software, the capacitance meter settings reset, and there's no automatic output enable.

Compared with the ZXY series converters, they're very similar. The screen is larger and the circuitry has been updated, but some functionality has been cut. The controls are about as convenient, though I prefer the ZXY's.
Compared with converters like the DPS-5020, the functionality is practically nonexistent, but the controls are more convenient. Also, the output voltage goes up to 60 V, which can be critical in some cases. The control and display response on the unit reviewed here is also better and closer to the ZXY. I liked the synchronous rectifier in the DPS; otherwise, the circuitry is similar.

One drawback I noticed is the encoder's odd behavior. If you turn it quickly, it starts to "slip". For example, instead of switching the adjustment step, I sometimes just turn the encoder more times—that's even faster than stepping through the ranges. You can't always do that here.
I also didn't like the left/set/right button layout. In my experience, left/right/set would be better. Better still would be to keep the ZXY layout: two buttons, set and cycle through the adjustment steps.

Overall, in my opinion, this converter series has potential. In some ways I liked it more than the DPS/DPH, but the design (or, more precisely, the software) is clearly "rough" and needs more work. I don't know whether the manufacturer will work on it or abandon it like the ZXY series. I'd still like to try the PC software, too.

That's all from me. Feel free to ask any questions about this board. I can already see the next question coming: is it on AliExpress? Yes, it is, and it costs almost $60.

This review was sponsored by the buying agent yoybuy.com, which covered the shipping costs. Affiliate link to sign up. New users get a 10-off-50 coupon, and maybe I'll get something out of it too :)
The kit cost $40.62 including shipping to the agent, and weighed 393 grams according to the agent's information (i.e. including the box). The shipping cost from the agent depends on various factors, such as the quantity and whether there are other items in the order.