6.4 Power Analysis

While in Software Shutdown mode, the Raspberry Pi board consumes 1.6W of power, whereas the total system power consumption including the PIC16F15245 control board is 1.9W. Assuming a Raspberry Pi system needs to be active for 12 hours a day, the approximate power saved for one day is 19.2 Wh (1.6W * 12h) . This power saved can further be improved if the PIC16F15245 microcontroller is put into Sleep mode. Table 6-1 gives the detailed power consumption of the application in Active and Sleep state with the Raspberry Pi board. In Active mode, the Raspberry Pi board consumes 2.5W, while the PIC16F15245 microcontroller on the Control board consumes 508 μW.

Table 6-1. Power Consumption of the Total Application System
System StateRaspberry Pi Power Consumption (W)(1)PIC16F15245 MCU Power Consumption (μW)(1)Total System Power Consumption (W)(1, 2, 3)
Active2.55082.9
Sleep06.60.03
Note:
  1. Current consumption values for the PIC16F15245 microcontroller are captured using Microchip Power Debugger hardware and MPLAB Data Visualizer software.
  2. The total system power consumption is the sum of the Raspberry Pi board power consumption and the PIC16F15245 Control board power consumption.
  3. In the ‘Total System Power Consumption’ column, the excess power consumption is due to the additional hardware present on the PIC16F15245 Control board, such as the voltage regulator (MIC4684), the Aux Regulator (MCP1702T), and filter circuit.