# A High-Conversion Ratio Multiphase Converter Realized with Generic Modular Cells
## 5 Simulation and Experimental Results
The average currents are equal to \(I_{L1}\) = \(I_{L3}\) = \(I_{\text{out}}\)/4 = 25 A and  
Figure 7: Simulation results of a single module where all duty cycles are equal: (**a**) top and second from the top plots—inductors currents, second from the bottom plot—output current, bottom plot—output voltage; (**b**) the voltages across all the switches: S\({}_{\text{1L}}\), S\({}_{\text{1H}}\), S\({}_{\text{2L}}\), S\({}_{\text{2H}}\), S\({}_{\text{2.3}}\), S\({}_{\text{3L}}\), and S\({}_{\text{3H}}\). \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**Power Stage**} \\ \hline
**Component** & **P/N** & **Value/Type** \\ \hline Input voltage-\(V_{in}\) & 48 V \\ \hline Output voltage-\(V_{out}\) & 1–1.5 V \\ \hline Switching freq\(\cdot f_{sw}\) & 333 kHz per Ph. \\ \hline Input capacitor-\(C_{in}\) & EEE-FK2A221 AV & 220 \(\mu\)F, 100 V \\ \hline Output capacitor-\(C_{out}\) & EEF-GX0D561R & 560 \(\mu\)F, 2 V \\ \hline Inductors-\(L_{1}\), \(L_{2}\), \(L_{3}\) & XAL1580\_401 MEB & 0.4 \(\mu\)H, 60 A \\ \hline Capacistors-\(C_{1}\), \(C_{2}\), \(C_{3}\) & C5750X7S2A106M & 10 \(\mu\)F, 100 V \\ \hline MOSFETs (\(R_{\text{DS,on}}\)) & NVMFD5C446 NL & 2.2 \(\mu\)M, 145 A \\ \hline Load resistance-\(R_{load}\) & 10–100 m\(\Omega\) \\ \hline \multicolumn{2}{c}{**Floating Driver**} \\ \hline Driver & 2 EDF/275F \\ \hline Isolated DC/DC & TDR 3-1212 SM \\ \hline \multicolumn{2}{c}{**Digital Section**} \\ \hline Microcontroller & dsPIC33 FJ16 GS502 & 16 bit, 40 MIPS \\ \hline Buffers and Drivers & MC74 VHC244 DWR2G \\ \hline \end{tabular}
\end{table} 
Table 3: Experimental prototype parameters. \(I_{L2}=2I_{\text{out}}/4=50\) A, similar to the case of equal inductances, maintaining current sharing for even the high inductance difference. The change that could be observed is in the current ripple. It should be noted that a CCM operation mode needs to be maintained to ensure current sharing and overall correct converter operation. Figure 8: Simulation results of a multiphase buck converter that consists of two (\(m=2\)) three-phase (\(t=3\)) modules, denoted 1 and 2, where all duty cycles are equal. The simulation demonstrates: (a) output voltage, output current and inductors currents, and (b) capacitors currents in soft charge/discharge mode and capacitors voltages. The currents and voltages per module are marked by numbers inside the brackets. Figure 9: Simulation results for the heavy load conditions and unbalanced inductances, where \(L_{1}=0.6\)\(\mu\)H, \(L_{2}=0.2\)\(\mu\)H and \(L_{3}=0.5\)\(\mu\)H, \(V_{\text{out}}=1\) V, \(I_{\text{out}}=100\) A. To validate the operation of the three-phase topology at a high voltage and high conversion ratio, a 100 W laboratory prototype that operates at a switching frequency of 333 kHz per phase was built and tested. Table 3 lists the components' values and nominal parameters of the experimental prototype. Each phase in the converter has been designed to be identical, as can be seen in the photograph of the experimental prototype (Figure 10). Each cell is comprised of an inductor, a flying capacitor that consists of two 10 \(\upmu\)F capacitors connected in parallel to reduce the ESR, and a dual N-Channel MOSFET. A microchip dsPIC33 controller is used to generate complementary gate waveforms for switches \(S_{\text{KL}}\) and \(S_{\text{SH}}\). The experiments are performed with an output voltage range of 1-1.5 V and maximum load of 100 A. Figure 11 shows the three-phase inductors currents and the output current, which is the sum of all three-inductors currents, (interleaved mode), i.e., \(I_{\text{o}}\) = 10 A and \(V_{\text{o}}\) = 1.5 V. We measured average capacitors voltages, and the output voltages are \(V_{\text{C1}}\approx 36\) V, \(V_{\text{C2}}\approx 24\) V, \(V_{\text{C3}}\approx 12\) V, and \(V_{\text{o}}\approx 1.5\) V, as demonstrated in Figure 12, and fully support the theoretical derivations. The existence of soft charge has been demonstrated by measuring the capacitors currents (Figure 13).