## 3 Description of the Measurement Set-Up  
Figure 3 shows a block diagram of the set-up for measuring the performance of the EVLONE140W dedicated mobile device charging system. The measurement system contains three interconnected functional blocks: Power supply block, Measurement block and Load block. The Power supply block contains the ATS-REG1.2 autotransformer, which allows an Alternating Current (AC) supply voltage to be obtained with an RMS value in the range from 0 to 230 V.  
The Measurement block, whose main components are the TCPA300 current probe by Tektronix (Beaverton, OR, USA), records waveforms of the supply current for further Fast Fourier (FFT) analysis of these waveforms. A Pintek (Shulin, New Taipei City, Taiwan) differential voltage probe, type DP-25, is used to record the waveforms of the supply voltage of the charging system under test. The current and voltage probes operate together with a GwInstek GDS2104 oscilloscope (New Taipei City, Taiwan), whose software allows a Fast Fourier Transformation (FFT) analysis of the recorded waveforms. The RMS value of input voltage V\({}_{\text{inRMS}}\) and current I\({}_{\text{inRMS}}\) are measured by a voltmeter and ammeter, similarly to the output current I\({}_{\text{out}}\) and output voltage V\({}_{\text{out}}\) of the tested charging system. All the considered voltmeters and ammeters are of the type Rigol DM3058E (Suzhou, China). The values of V\({}_{\text{inRMS}}\) and I\({}_{\text{inRMD}}\) are analyzed using a Tektronix PA1000 power analyzer. This analyzer allows the coefficients of total harmonic distortion of the THD\({}_{\text{I}}\) current and THD\({}_{\text{V}}\) voltage to be measured and the power factor (PF) of the charging system under test to be measured. The Device Under Test (DUT) block contains the charging circuit under test operating in the USB PD 3.1 mode. According to the data given by the manufacturers of the used instruments, the uncertainty of the measurements of the output voltage is described as the sum of 0.015% of the measured voltage and 0.03% of the measurement range. For the output current, the uncertainty is smaller as it is the sum of 0.25% of the measured value and 0.01% of the measurement range. In turn, the uncertainty of measurement of the RMS values of input voltage and current is smaller than the sum of 0.1% of the measured value and 0.1% of the measurement range. The uncertainty of the measurement of power is equal to the sum of 0.075% of the measured value and 0.075% of the range value. The value of uncertainty of PF depends on the phase shift between the input voltage and the input current, and it is not smaller than 0.002. The measurement set-up analyzed also includes a Load block that allows the system under test to be loaded with a resistor from 1 \(\Omega\) to 10 k\(\Omega\), as well as charging the batteries of  
Figure 3: Measurement set-up scheme. selected mobile devices. A switch S was used to switch the type of load. In the experimental tests, the performance of the test charging system was recorded for selected State of Charge (SoC) levels from 10 to 90%. During the experiments, two mobile devices with different battery capacities were selected. The Galaxy A23 5G smartphone (SM-A236B) manufactured by Samsung (Suwon, Republic of Korea), which contains a Li-Po battery with a capacity of 5 Ah and a voltage rating of 3.7 V, was selected as the first device for the experimental study. The other mobile device was the ThinkBook 14 G2 ITL Notebook manufactured by Lenovo (Beijing, China), which contains a Li-Po battery with a capacity of 3.8 Ah and a voltage rating of 11.55 V. The two mobile devices also differ in the maximum power with which they can be charged; for the smartphone, it is 25 W, while for the notebook, it can be as high as 65 W. Figure 4 shows a view of the measurement set-up.