To accurately ascertain the efficiency of the MCU driven design, it is essential to know the current consumption of the MSPM0 when it generates dual-channel PWM signals. This test is conducted on the MSPM0L1306 Evaluation Module (EVM) board, with the test configuration depicted in Figure 2-11. Measuring the current consumption of the MCU when driving the half-bridge (connect the green wires), and then subtracting the current consumed by the MCU running an empty program (disconnect the green wires), yields the specific current used for generating dual-channel PWM signals.

As per the MSPM0L1306 LaunchPad Development Kit User's Guide, in Section 2.6, an external power supply is utilized instead of USB power from a PC. The MSPM0L1306 is in "Free Run" mode and disconnect programming signals between the MSPM0L1306 and the debug portion of the board (header J101).

Current measurement is facilitated by a shunt resistor, placed between the power supply's positive terminal and the 3V3 pin on the MSPM0L1306 EVM board, by measuring the voltage drop across the resistor. To prevent any extraneous current consumption that can be caused by floating I/Os, all unused GPIOs are actively set to low. Additionally, to isolate the microcontroller from any parasitic loads, all other jumpers, especially those connected to indicator LEDs, are disconnected.

Figure 1-5 displays the current consumption of generating PWM signals with different frequency at different power supply voltages from 1.8V to 3.6V. Red line shows the current consumption of 250kHz switching frequency with 45.3% duty cycle, black line shows the current consumption of 50kHz switching frequency with 49% duty cycle. As the power supply voltages increases, the current consumption also increases. Specifically, at a higher switching frequency of 250kHz, the current consumption is significantly greater across all power supply voltages compared to the lower frequency of 50kHz.