A Scalable Hybrid Multilevel Power Converter Using Low-Voltage On-Chip Power Modules

This manuscript presents a hybrid architecture for scalable multilevel power conversion based on integrated binary-tree multilevel converter (BTMLC) modules and discrete switching stages. The proposed approach partitions voltage synthesis across two domains: high-frequency switching and level generation are implemented on-chip using low-voltage semiconductor devices, while highervoltage stages are realised using discrete switches operating at lower switching frequencies. This strategy enables high-performance voltage synthesis from battery-cell voltage levels while extending the overall voltage capability beyond the limits of the semiconductor technology. To enable this architecture, an integrated eight-battery-tap BTMLC module is designed and implemented to dynamically select individual cell voltages and synthesise high-resolution pseudo-sinusoidal waveforms or arbitrary voltage patterns. Novel circuit techniques are introduced to generate gatedriver supply rails for both high-side and low-side switches using low-cost low-voltage devices, with the required rail voltages derived directly from the battery stack. The complete module, including power stages, control logic, gate drivers, level shifters, and protection circuits, is fabricated in a 130-nm BCD process using LDMOS power devices. Experimental results from a 20.52-mm2 silicon prototype demonstrate reliable operation and efficient driving of multiple converter switches with low on-state resistance. The converter is packaged in a commercial J-leaded chip carrier for baseline validation and also integrated into custom PCB assemblies with manually wire-bonded chips to reduce conduction path resistance. The scalability of the proposed hybrid architecture is demonstrated by stacking two BTMLC modules and combining their outputs using an off-chip half-bridge stage. Measurements confirm variable-frequency and variable-magnitude waveform synthesis while delivering up to 6A to a resistive load with a peak efficiency of 98.5%.