MPS Four-Channel Output Power Module EVM - Review

Table of contents

RoadTest: MPS Four-Channel Output Power Module EVM

Author: scottiebabe

Creation date:

Evaluation Type: Development Boards & Tools

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: ADI µModule & LTpowerPlay. Many of the power modules in market are single output, the MPM54304 has up to four outputs.

What were the biggest problems encountered?: Virtual Bench falling out of sync with the EVM after power cycling the EVM.

Detailed Review:

The MPM54304 is a fully programmable 4 output synchronous DCDC buck converter module with integrated magnetics housed in a 7x7 mm LGA package. The I²C interface allows for configuration of virtually every operating parameter of the power module. The only operating parameter that is limited is the current rating of the internal magnetics. Provided your target application’s power requirements are for 4 voltage rails operating below 5.4V with 3A/2A of load current, the MPM54304 MPM54304 can be custom tailored to the application.

 

This RoadTest review is based on a promotional kit which included the following MPS development/evaluation products:

 

 

 

An Evolution in Power

The level of performance and integration of this power module in contrast to legacy power products is really quite remarkable.

This product has given me a lot to think about, on how to best make use of it. Previously you would configure/program a power product either by:

 

Part Number Selection: Ex. 78xx (xx for desired output voltage)

Pin Strapping/Feedback Divider: Ex. LM317

 

With the MPM54304 you can either program the module yourself, or order it factory programmed to your specifications under a custom part number.

While I haven’t personally tried using this service, the idea that MPS are offering a custom programmed power solution in prototype volumes, is just awesome.

 

RoadTest Prototype

To evaluate the MPM54304, I constructed a very simple multi-rail blinky LED prototype.

With the EVM PCB having every output pinned out, integrating the EVM into a prototype build was easy.

For this prototype, we need to configure the MPM54304 to provide the following supply rails and their accompanied sequencing requirements:

Software Installation

I had to spend a few minutes searching around the MPS website to find the software configuration tool for the I²C dongle. The quick start guide for the EVM only says, download the GUI…

This absolutely should have provided a link to the Virtual Bench download page and user’s guide. I also don’t know why virtual bench isn’t listed on the https://www.monolithicpower.com/en/design-tools/design-tools.html webpage, that was the first place I looked. Once I managed to find it hiding in plain sight on the MPM54304 product page, the tool installed effortlessly on Windows 10.

Virtual Bench

When you combine the MPS USB-I²C dongle with a MPS programmable power product, virtual bench serves as comprehensive development and evaluation tool. Virtual bench presents every register bit field in a clear and easy to understand description (voltage, phase, slew-rate, etc.). Provided you have familiarized yourself with the power product’s datasheet, I believe anyone would find the use of virtual bench to be intuitive.

 

The tool is very minimalist, for example if you would like a 5V output, you have to enable the divide by 3 feedback divider and set the reference voltage to 1.67 V. As opposed to, requesting a 5V output and the tool suggesting the optimal registers settings.

Below is a video walking through Virtual Bench Pro 4 to configure an MPM54304 for the RoadTest LED project.

 

[Video walking through register settings]

 

You may have noticed the auto-connect feature failed. That doesn’t really bother me, If I were to use this I²C dongle on a live system’s PMBUS or I²C bus I wouldn’t want virtual bench configuring I²C devices based solely on an address ack. The process of manually adding new power product to virtual bench was simple. The tool reminds you how I²C addresses are configured for the product and choice becomes very clear.

 

Virtual Bench allows you write your register settings to either volatile memory or to an OTP memory bank (you get 3 banks with the MPM54304, 1 is already used by MPS). Also watch how well the regulator’s output voltage tracks the DAC generated reference setpoint, it is within 1 mV!

 

 

If you examine the exported register table generated by virtual bench, it would strongly support the idea that the MPM54304 has its DAC output factory calibrated.

 

My only complaint with Virtual Bench is how the I²C register writes are scheduled. They appear to be based on what bit fields have changed in the GUI since the last memory write. So, if you power cycle the EVM and try to write your project registers settings to the DUT, nothing happens. I would like to see the write error and indicate that the DUT registers mismatch the project.

 

Overall Takeaway: Performance and Flexibility

EVM + I²C Dongle

The MPM54304 EVM was able to stepdown 12V to 5V with 90% efficiency into a 30W load.

I was able to workaround a supply sequencing issue using the extensive configuration options of the MPM54304.

The setpoint accuracy of the MPM54304 is almost on par to a top-tier TL431 reference over temperature.

The EVM as a prototyping and development board presents exceptional value. As demonstrated in this roadtest within just a few hours the first time, less than hour to do it a second time, you have a fully custom power solution.

A silkscreen outline of the 10-pin ribbon cable on the EVM would have been nice.

I think the EVM should have its outputs disabled by default and require you enable them via the I²C dongle. If you power cycle the EVM the volatile register settings are lost and will power up with the 3.3/1.8/1.5/1.1 default rails. That’s okay if you are only characterizing the EVM, but not ideal if your are trying to validate the EVM in a target application.

 

Power Module - MPM54304

4 High efficiency, fully programmable buck converter outputs

Only requires 8 additional MLCC capacitors and voltage divider on the enable input.

All high current switching loops have a copper path on the component load side.

The recommend PCB layout is easily replicated, with basic polygon pours.

Minimal upfront design effort.

Still requires system integration for thermals and noise (that’s the just the present reality of a 7x7mm solution, the module can’t dissipate 4W to ambient and maintain an acceptable operating temperature without using the PCB as a heatsink).

All their present chips default to powering up with some common rail voltages.

I was not able to find any literature or guidance on in-circuit programming best practices.

 

References:

[1] EVM Schematic: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Schematic/lang/en/sku/EVM54304-MN-01A/document_id/9463/

[2] EVM PCB Layout: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Layout/lang/en/sku/EVM54304-MN-01A/document_id/9464/

[3] EVM Datasheet: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/EVM54304-MN-01A/document_id/9460/

[4] Altium Viewer: https://www.altium.com/viewer/

[5] Simplis Model: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/MPSmart%20Model/lang/en/sk…

[6] Virtual Bench Pro: https://www.monolithicpower.com/en/virtual-bench-pro-4-0.html

[7] MPM54304 Datasheet: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MPM5…

[8] MPS MPM54304 EVM RoadTest - Snippets

 

Please enjoy an LED fireworks show made possible by the MPM54304 30W output capability:

Anonymous
  • Ah, that makes sense. Those are not things I considered.

     

    I wonder if the intent is to use the I2C stuff during the prototype stage and then order a customized version for production.

  • Well if you order the module factory programmed, then you just solder it on to your board and you have a custom power solution.

     

    If however you elect to program it yourself it becomes a chicken egg conundrum, the processor needs to be powered to program the power supply but the power supply isn't programmed. So, if you need to program with an external I2C master (not the processor on your board) how do you prevent the module from powering up misconfigured and other gotchas like the processor's ESD diodes clamping the i2c bus. I think its a complicated enough task that MPS should author an application note on the topic.

     

    Of course there are less digital styles of using the module using feedback dividers for each output, which will get you close enough to have a processor booting at which point you can program or adjust any of the outputs over I2C like you would any other I2C peripheral.

     

    Lots to ponder! But, really neat product.

  • A programmable module like this does seem ideal in an Adafruit style product. I just wish Newark didn't show stock availability of September 2022! Sigh.

     

    Regarding your roadtest:

    "I was not able to find any literature or guidance on in-circuit programming best practices."

    Did you mean you did not find documentation on how to program it without I2C?

  • Thank you for the kind words. I tried to keep the project as simple as possible to not take away from the star of the Roadtest the product under review. I am quite thrilled with how well the converter preformed. 30W spread along 2 ws2812b led strips is an impressive amount of light at night!

     

    If I can see an airplanes navigation lights in the sky, I'm sure they must have seen my blinky LEDs .

  • Thanks Enrique. Interestingly, none of the common breakout board/module stores like sparkfun and adafruit offer anything related to this component either.

     

    But they do distribute dozens upon dozens of DCDC modules like this:

    I suppose MPS is trying to get the word out they have some pretty great products.

  • Well done!  I really like road tests where a project is built to test the product.  This seems liked a very good test of capabilities of the product.

  • Very good road test report.

     

    DAB

  • Great road test .

    I did not know anything about this type of programmable converters.

    It was great to see almost in the first person how they work. Thanks.