Microchip dsPIC33C Digital Power Starter Kit - Review

Table of contents

RoadTest: Microchip dsPIC33C Digital Power Starter Kit

Author: vu2iti

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?: Microchip - DM330017 - Starter Kit,

What were the biggest problems encountered?: A dry solder in the board caused malfunctioning of the board.

Detailed Review:

ROAD TEST REPORT ON dsPIC33C DIGITAL POWER STARTER KIT USER’S GUIDE

By

T .K. MANI

I am fortunate enough to be selected as a road tester for the DSPIC Power starter kit.

The kit contents received are Starter kit PCB, a 9V Power supply with universal adapters and a USB cable. With curiosity, I opened the box verified all things in the kit.

The manual (downloaded from Microchip website) clearly explains the schematics and the demo software already programmed on the DSPIC chip.  

The user manual says that the kit has two DC to DC converters, one the buck converter and the other a boost converter, driven and controlled by the dsPIC33CK256MP505. The kit has a built-in demo program.

Figure 1: DSPIC starter board top view

I took out the board, connected to power supply and switched ON. The two-line LCD display came alive, scrolling messages and showing the Kit name (DIGITAL POWER STARTKIT 3), firmware version (v1.0) and Hardware version (v.3.0).

I pressed the user button on the board and then the display showed the message Vbuck = 3.30 on the top line and Boost = 15.01 V in the second line of the in-built display. It is observed that the display back light intensity is too much and slightly annoying to the eyes. See figure 1.

There are two connectors at the right edge of the PCB, one to connect the Buck output voltage to the external load and the other for Boost output voltage output. Two buttons are closely placed to the output connectors for varying the built-in load resistors by connecting and disconnecting across the outputs. These resistive loads are beautifully placed with adequate heat dissipation facility.  Three LED Indictors on the load buttons lights up to indicate the load every press of the push button 10% > 50% > 100% > 10% in a sequential way.  There is no overheating of the board even with the full-on board load connected is observed.

With a True RMS multimer, measured the output voltages and found good and agrees with the readings shown on the LCD Display.

This board contains an onboard debugger and programmer. Using the USB cable, it is easy to develop programs, compile and load it to Chip and debug and test the program developed by the user.  It is also very easy to develop control loop algorithms by using the user accessible onboard analog hardware circuit and signals. 

One drawback that I noticed about the kit user manual is there is no detailed explanation on how to connect the board to MBLAB Ide or to any development platform and use it for developing user programs. It would have been better to add some tutorial on how to develop and test the user applications using the DSIPC power development kit.

After the initial testing, I decided to observe the output voltage on a DSO. I used R&S RTM3004 to observe the output.

To my surprise I noticed that the boost output RMS voltage is changing from 15 V to 13.25 Volt when load is varied. It is also observed that the output voltage display is not clean. The oscilloscope displays are as shown in figure 2.

 

  Figure 2a: Noise in the boost O/P Voltage

Figure 2b Noise: zoomed time scale

I

I compared the noise level of the Boost voltage output with the buck voltage output and confirmed the noise level is acceptable for buck but not for Boost output.

On close examination of the PCB, I found what was wrong: the electrolytic capacitor C44 soldering was imperfect. There was a dry solder, and the capacitor was hanging on one leg! See figure 3.

Figure 3: Dry soldering in the capacitor lead

Tested the board again after re soldering the capacitor.  This time everything went on well. The output is very clean and stable even on full load. 

The 3.3 V output is found rock stable from no load to full load.  For the Boost output, it is found that, while switching from full load the no load, Output voltage produced a glitch as shown in the figure 4.

Figure 4. Glitch in the output when load switched off.

Conclusion:

The DSPIC starter kit is easy useful to develop application programs, compile and load it to Chip and debug and test the program developed by the user.  There is no need of separate programmer. It is very handy to develop control loop algorithms by using the user accessible onboard analog hardware circuit and signals. 

One drawback that I noticed about the kit user manual is there is no detailed explanation on how to connect the board to MBLABX Ide or to do any development platform and use it for developing user programs. It would have been better to add some tutorial on how to develop and test the user applications using the DSIPC power development kit.

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