dsPIC33AK Digital Power Starter Kit (DPSK4) (Part-No. DM330017-4)
Voltage mode control example for the buck converter on the Digital Power Starter Kit, version 4 (DPSK4) featuring the dsPIC33AK family of devices.
This code example demonstrates the implementation of a simple voltage mode control loop regulating the output voltage of a synchronous buck converter. The loop implementation also includes the required state machine managing board status analysis, start-up control, operation monitoring, fault handling and auto-restart capability. The buck converter state machine is based on a generic library package, which is configured in user code and executed by a main task scheduler.
This code example also includes the LCD driver allowing users to observe runtime data on the on-board LC display. The on-board user switch USER can be used to change the active display page to observe input voltage, output voltage, output current, board temperature and most recent firmware version.
- dsPIC33CK Digital Power Starter Kit 4 User's Guide
- dsPIC33AK512MPS506 Family Data Sheet
- dsPIC33AK512MPS506 Family Silicon Errata and Data Sheet Clarification
- dsPIC33AK Digital Power Starter Kit, Part-No. DM330017-4
a) Power Supply Circuit
- 8-MHz MEMS Oscillator, DSC6011JI2A-008
- 50V/1A, Asynchronous Buck Regulator, MCP16331
- 16V/300mA Low Quiescent Current LDO with Shutdown and Power Good, 3.3V, MCP1755-330
- High-Speed Low-Side MOSFET Driver, MCP14A0152
- Dual Input Synchronous Half-Bridge MOSFET Driver, MCP14700
- High-Speed N-Channel MOSFET, MCP87130
- Active Thermistor Temperature Sensor, MCP9700
b) Protection Circuit
- P-Channel Enhancement-Mode MOSFET, TP2104
- 36V Open-Collector Comparator, MIC6270YM5
- Windowed Comparator with Adjustable Hysteresis, MIC841H
- 50V/5A Schottky-Diode, HSM560JE3
c) Communication, Programming/Debugging and Housekeeping
- 2-Port USB 2.0 HUB Controller, USB2422
- USB 2.0 to I2C/UART Protocol Converter, MCP2221A
- 44-pin MCU PIC24FJ64GA004
Unattended operating power supplies are always a potential safety risk as short circuits or failures of power components can occur at any time where even seemingly small power converters can cause fire or damage connected equipment.
- This development board has not been FCC approved nor certified and must not be used outside a laboratory environment
- Never operate the board unattended
- Only use power supplies delivered with the board or equal, approved laboratory equipment
- Read the user guide for detailed operating instructions to prevent damage to the board or connected equipment
- Connect dsPIC33AK Digital Power Starter Kit to the PC using the micro-USB cable
- Open and compile the firmware; program the target device
- Attach the 9V power supply to the board and observe the run-time values on the LC display
DPSK3 Buck Converter Test Points
After the device has been programmed and the target device starts up, the LC display will show the startup screen for approx. 3 seconds before switching to the runtime data display, showing the most recent input and output voltages. In case an appropriate power supply has been attached to the DPSK3 power input and the firmware is running correctly, the display should show an output voltage of +3.30 V DC.
By pressing the on-board button USER once, the screen can be switched between the following display options:
- Output Voltage View
- Output Current View1
- Temperature View
- Firmware Version
By pressing the on-board button USER for longer than a second, the operation of the buck converter will switched between active feedback loop and open loop plant. The screen display the following to indicate the operation:
- VIN PT: Open Loop Operation
- VIN: Closed Loop Operation
By pressing the Buck Load on-board push button on the right edge of the board for less than a second, the constant, resistive load level can be changed in four steps. The most recent load level will be indicated by three LEDs located next to the Buck Load on-board push button:
- no LED: 0% (0 mA)
- 1 LEDs: 10% (100 mA)
- 2 LEDs: 50% (500 mA)
- 3 LEDs: 100% (1000 mA)
(value accuracy +/- 10% @ output voltage of +3.30V DC)
By pressing the Buck Load on-board push button on the right edge of the board for longer than a second, the load switches into stepping mode.
- Flashing LEDs indicate the upper step limit
- Static LEDs indicate the lower step limit
Pressing the Buck Load on-board push button again for less than a second, the step load can be adjusted between
- 10% to 50% Load (100-500 mA)
- 10% to 100% Load (100-1000 mA)
- 50% to 100% Load (500-1000 mA)
(value accuracy +/- 10% @ output voltage of +3.30V DC)
For more information, please read the Digital Power Starter Kit 4 User Guide.
© 2025, Microchip Technology Inc.
Footnotes
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Inductor current is continuously measured and displayed but is not used by the control loop ↩