Tiny Miniware MDP-P906 Digital Power Supply Provides up to 30 V and 10 A (Review)

Every maker and professional developer values desk space. Lab benches become quickly crowded with oscilloscopes, multimeters, and power supplies. Power supplies are particularly bulky and take up a significant amount of room. To address this issue, Miniware has devised an ingenious solution: the Miniware MDP P906. This device converts any DC power source into a stable, precise, and regulated lab power supply. It accomplishes this task within the compact size of a USB hub and even offers a wealth of features.

Overview of the Miniware MDP P906

The system that we look at in this article comprises two Miniware modules (Figure 1):

•    MDP-P906 Digital Power Supply
•    MDP-M01 Smart Digital Monitor
 

The MDP-P906 digital power supply has a small OLED screen, three push-buttons and a rotary encoder. This minimalistic design is well enough to do its job with excellence.

The MDP-M01 Smart Digital Monitor with its 2.8-inch TFT screen provides a display and controls for the power supply. The screen can rotate upwards by up to 90 degrees, which is convenient for viewing anywhere on a bench. The  modules communicate with each other wirelessly at 2.4 GHz. One MPD-M01 can control up to six other modules simultaneously.

Just the Beginning

Other modules like a digital signal generator, an electronic load, a power charger and a battery pack have been announced.

The products come in high-quality boxes that protect them and contain accessories like cables and manuals. The cables provided for connecting circuits to the P906 feature gold-plated tips and high-quality silicon coating. The units themselves are also of solid quality, with an aluminum housing and gold-plated terminals.

Specifications of the Miniware MDP P906

Miniware MDP P906 Digital Power Supply

• Input: 4.2 VDC - 30 VDC, 14 A (max) or QC3.0/PD2.0 20 V, 5 A (max)
• Output: 0-30 VDC, 0-10 A, 300 W max
• Output resolution: 10 mV, 2 mA; up to 1 mV, 1 mA via Smart Digital Monitor
• Output accuracy: 0.03 % + 5 mV
• Load adjustment rate: < ±0.01 %
• Power adjustment rate: < ±0.01 %
• Ripple and noise: < 250 µVRMS, 3 mVPP; < 2mARMS
• Transient response: < 4 µs
• Input protection: overvoltage, undervoltage, reverse connection
• Output protection: overcurrent, back-flow and overtemperature
• Automatic shutdown and micro-power mode
• Size (not including rubber feet): 112 mm x 66 mm x 20 mm
• Weight: 181 g

MDP-M01 Smart Digital Monitor

• Screen size: 2.8” TFT
• Screen resolution: 240 × 320
• Input: 3.6 VDC - 5.5 VDC, 0.1 A
• Controllable channels: 6
• Size: 107 mm × 66 mm × 14 mm
• Weight: 133 g

Miniware MDP P906, the Powerful Dwarf

Despite its small size, the MDP-P906 can deliver up to 300 W (30 V, 10 A), which is more than enough for most applications, for makers as well as for professional users. To handle this high power, the MDP-P906 has a fan built-in which very quietly cools down the electronics inside.

The Miniware MDP P906 relies on an external power supply to convert the mains AC into an appropriate DC input. Any power supply, switched-mode or linear, is suitable. The P906 acts as a precision DC-to-DC converter to replace traditional lab PSUs. Nearly any DC source capable of providing a voltage between 4.2 V and 30 V will do. This ranges from battery packs via wall warts and laptop AC adapters to USB ports of hubs or even desktop computers (see Figure 2). The digital power supply also sports a USB-C (Quick Charge 3.0) input.
 

An advantage of this solution is that, for instance, the AC unit can be placed under the bench, leaving only the compact power converter unit on the bench. With a rechargeable battery like a power bank, it offers even greater flexibility. This turns it into a capable portable universal power supply.

A standard USB port on a PC is usable too. Of course, the available power in this case is limited and depends on the port's specifications. But on a crowded bench, having easy access to a 15 V/300 mA or similar supply can be convenient.

In short, the MDP-P906 is a neat little power converter that transforms (nearly) any DC source into a stable, precise and regulated power supply.

Add a Smart Digital Monitor

The digital power supply can work stand-alone, or together with the MDP-M01 wireless display/control unit. The MDP-M01 has a large display, and push- and rotary controls to command several other modules simultaneously. It is powered via a micro-USB cable (included) by the digital power supply. The cable supplies only power, as communication between the units is wireless.

Although communications are over Wi-Fi, the maximum distance between the display/control unit and the power supply is about two to three meters. That is not a lot, and it somewhat limits the possibilities for controlling up to six units on a bench or around a room.

Performance

The digital power supply has an output range from 0 V to 30 V and can deliver up to 10 A of current. This, of course, depends on the input power source. The P906 has a conversion efficiency of up to 95%. Therefore, as an example, with a 19 V/4.25 A (80 W) laptop power adapter the P906 can deliver:
 

• 3.3 V, up to 10 A
• 5 V, up to 10 A
• 12 V, up to 6 A
• 25 V, up to 3 A
• 30 V, up to 2 A

or anything in between. Even a 5 V/1 A USB (phone) charger can be boosted to 12 V, 15 V or even 30 V, still providing 0.3 A or more.

Accuracy, Stability and Noise

The stability and precision of the values shown on the digital power supply’s display were verified with a calibrated HP E2377A multimeter. The results confirmed the high precision of the MDP-P906 readings (Table 1).
 

MDP-P906 (V)	HP E2377A (V)
0.110	109.9 mV
3.008	3.013
5.006	5.009
9.997	10.00
19.991	20.01
29.792	29.82

Table 1. Comparing displayed and measured output voltages.

Such precision should be good enough for all practical applications. Target as well as measured voltage values are highly accurate; current values were always spot on. Current limiting also works perfectly, with precision down to the milliamp level.

The voltage regulation is also excellent (Figure 3). Voltage fluctuations can barely be observed using a normal high-quality DMM. The observed voltage drop at 5 V with a load from 0 V to 3 A was less than 10 mV.

All measurements were carried out using the 4-point Kelvin (4-wire) sensing method, taking voltages directly at the output connectors.
 

Also, the load regulation is excellent and fast. Figure 4 shows that the voltage peak generated by a load change from 0 A to 1.5 A is less than 150 mV and shorter than 1 µs.
 

The noise level is extremely low: < 0.8 mV_PP at 30 V with a 3 A load. Of course, the noise level depends on the quality of the input power supply. If very low noise levels are required, a battery should be used as the primary power source. In any case, the circuitry of the MDP-P906 provides excellent filtering.

Comparing the MiniWare MDP P906 with a linear bench PSU like the HP 3612A shows similar peak-to-peak and RMS ripple values. A test carried out at 5 V with a 2.5 A load gave the following results (Table 2):
 

Power Supply	VRMS	VPP
MDP-P906	±350 µV	1.25 mV
HP 3612A	±450 µV	1.50 mV

Table 2. Comparing RMS and peak-to-peak values.

High-Power Test and Protection

For high-power tests, a set of 50 W resistors was used. The test was done at 5 V, 10 A (50 W) and repeated at 15 V/3 A (30 W) and 25 V/2 A (50 W). All measured values were well within the specifications. Finally, for an illustrative demonstration, a 12 V/4.25 A (sold as 50 W) halogen lamp was connected. The primary power source was a li-ion battery pack (nominal 3.8 V/20 A). As Figure 5 shows, the digital power supply accomplishes this task admirably, and the lamp shines at full power.
 

Short circuit protection also works very well. Even at high voltage- and current settings, no sparking and no damage to either the connected circuits or the PSU was observed. Thermal protection is present too, but it is hard to reach the point where a thermal shutdown is necessary. Only at ambient temperatures of over 30 °C might it come in handy.

Handling and Ease of Use

As every experienced user knows all too well, a lot can go wrong when operating power supplies. Incorrect settings can quickly lead to substantial and costly damage to connected parts and circuits. Even fire can start, and explosions can happen when voltage or current limits are set incorrectly. A badly designed user interface increases the chance of operator mistakes. Fortunately, the risks are limited with the P906 thanks to its easy-to-use interface. A rotary encoder controls parameter values, while the three buttons select the respective parameter, open the main menu, and start and stop power delivery.

Main Menu

The main menu offers only the basic options like changing the voltage and current limits. The display shows the output voltage (V), output current (A) and the power being output (W).

After pressing the menu button, information about temperature and version numbers can be obtained. Also, the input values can be displayed, which is useful for troubleshooting when approaching the limits.

Rotary Encoder for Ease of Use

The rotary encoder works fine and makes setting voltage and current limits easy. When the output is disabled, the display shows the target values. Pressing the first button cycles through parameters, clearly presented on the display. Setting parameters while the output is active is also possible without problems. Output voltage and current measurements are still displayed, while the output power value is temporarily replaced by the new setting’s value.

Somewhat inconvenient is that before spinning the dial, the only indication of what is about to change is a tiny letter in the center of the screen. This creates the risk of adjusting the wrong parameter accidentally. Sensitive circuits like microcontrollers may not like an unintended voltage adjustment.

Graphical Representations

The display module (Figure 6) shows the controls for individual MDP module stacks and can plot charts for voltage and current. Apart from showing the actual values, the unit can also change the voltage and current settings on the fly. The timescale for the graphs can be adjusted using the encoders and buttons on the unit. They also allow for toggling the outputs remotely and changing views.
 

The Smart Digital Monitor certainly offers some advantages. However, when used with only one digital power supply, it can be easily dispensed with. It will probably be more useful when monitoring and controlling multiple (up to six) power supplies simultaneously. In this case, the wireless control allows individual power supplies to be placed there where they are needed, at the point of load.

Pros and Cons of the Miniware MDP P906

Finally, it is time to consider the advantages and disadvantages. On the pro side, the following points can be emphasized:

+ Extremely compact and robust design
+ Superb accuracy
+ Can be battery operated
+ Ease of use

However, there are also some disadvantages to consider:
                                                                                                                                                                 
- Limited range of the wireless connection between MDP-P906 and the smart monitor MDP-M01
- The manual sometimes contains unclear or difficult wordings
- The display unit is of limited use with a single power converter module

Conclusion

The MiniWare MDP P906 Digital Power Supply is useful in professional applications as well as for people who take their electronics hobby seriously. The device does what you expect of it in a very satisfying way. Even though it may be more expensive than other PSUs with similar specifications, it is worth the money. The MDP-P906 is a fantastic space saver, and considering the functions it offers, I can highly recommend it. The Smart Digital Monitor, however, is not indispensable, especially when used with just one power supply.