A Battery-Connected Symmetric Modified Multilevel Ladder Converter Achieving 0.45W/mm2 Power Density and 90% Peak Efficiency

A symmetric modified multilevel ladder (SMML) DC-DC converter is presented which relaxes the trade-off between efficiency and power density by employing an inherent phase interleaving between the SC phases and by reducing the current ripple in the inductor, both allowing for reduced conduction losses. In addition, the SMML topology minimizes or eliminates the circuit overhead required in conventional multilevel converters to generate extra supply rails for the drivers and to balance the flying capacitors, allowing the converter to be solely powered by a Li-ion battery. A prototype shows the converter can achieve a power density of 0.45W/mm
²
, a peak efficiency of 90%, and can provide conversion ratios up to 15× with efficiency >70%.