The following sections provide an introduction to Digital Power Starter Kit, links to relative documentation and required tools to support hardware.
Project consists of the main application which drives the buck/boost converters implementing peak current mode control. The second application is for the load control and protection components. Both firmware projects include a cooperative scheduler that runs all system level tasks and includes a 100us real time task handler. Common 1ms, 10ms, 100ms, and 1s task handlers are provided and used as needed. Majority of functions are task based but there are several core components being interrupt driven.
- dsPIC33AK512MPS506 for power controller
- 5W Buck and Boost Converters
- On-board resistive loads
- LCD for displaying hardware specific data
- dsPIC33CK256MP305 for load control and HW protection
- USB-C for console communication and programming/debugging through PKOB
- TA100 for advanced cryto features
- Loop injection HW for advanced converter loop analysis
- dsPIC33AK512MPSxxx Product Website
- dsPIC33AK512MPSxxx Device Family Data Sheet
- dsPIC33AK512MPSxxx Device Family Silicon Errata and Data Sheet Clarification
- Requires MPLAB® XCDSC Compiler, Version v3.30 or later
- Requires dsPIC33AK-MP Series Device Support DFP, Version v1.3.185 or later
- Connect dsPIC33A Digital Power Starter Kit to PC using USB type-C cable
- Open and compile the firmware; program the target device with on-board PKOB
- Attach 9V power supply to connector J1
DPSK4 Test Points
After the device has been programmed and the target device starts up, the LC display will show startup messages for the first few seconds. To switch to the runtime data display, the application will request pressing the on-board USER button. With an appropriate power supply attached and the programmed FW running correctly, the display should now show the buck/boost output voltages +3.30 VDC and +15.0 VDC.
Pressing the USER button again will change the displayed messages on the LCD screen between:
- Output Voltage
- Power Settings (buck/boost)
- Input voltage / Temperature
- Application faults
- Home screen startup messages
Pressing the Buck/Boost Load on-board push buttons (right edge of the board), changes the static load level in four steps:
- No Load (no LEDs): ~0 mA
- 10% Load (1 LED): ~100 mA
- 50% Load: (2 LEDs): ~500 mA
- 100% Load (3 LEDs): ~1000 mA
Pressing the Buck/Boost Load button for more than a second, the load switches into stepping mode where flashing LEDs indicate the upper step limit and static LEDs indicate the lower step limit.
A quick press of the Load buttons again changes the step load between the three states below while a long press (>1s) will exit stepped mode.
- 10% to 50% Load Step (100-500 mA)
- 10% to 100% Load Step (100-1000 mA)
- 50% to 100% Load Step (500-1000 mA)
With an oscilloscope, the cycle-by-cycle peak current mode action can be captured for both converters.
For the boost converter, connect oscilloscope probes as follows:
- TP49: Boost converter current feedback
- TP9: DAC_OUT - Reference (Boost current reference)
- TP32: PWM2H - boost drive
- TP42: Boost converter voltage feedback - usefull for transient tests with this channel in AC mode
For the buck converter, connect oscilloscope probes as follows:
- TP38: Buck converter current feedback
- TP35: DAC_OUT - Reference (Buck current reference)
- TP31: PWM1H - buck high-side drive
- TP30: PWM1L - buck low-side drive
- TP34: Buck converter voltage feedback - usefull for transient tests with this channel in AC mode
Under light load conditions, the buck converter enters into a burst mode and both the low-side FET and high-side FET are disabled while the peak current remains high between PWM cycles. This can be captured during no/light load conditions.
Buck Converter Scope Plots
For more information, please read DPSK4 User's Guide.
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