A Compact Cuk-Based Differential Power Processing IC With Integrated Magnetics and Soft-Switching Controller for Maximized Cell-Level Power Extraction

In this article, a cell-level differential power processing integrated circuit (IC) is presented to perform maximum power point tracking on photovoltaic cells under mismatch conditions, such as partial shading. To reduce the form-factor of the design, a bidirectional Cuk-based converter is implemented by integrating magnetics on the packaging bond wires. Using variable frequency TCM, a novel closed-loop soft switching controller is proposed to guarantee zero voltage switching (ZVS) for a wide operating range, regardless of process and component variations. To evaluate the stability and performance of the proposed nonlinear soft switching controller, a detailed analysis is provided using the phase plane portrait. In addition, a modified low-drop bootstrap circuit is presented to provide the floating voltage supply for the high-side switches in low-voltage applications. The proposed differential power processing IC is implemented in a 130 nm complementary metal-oxide semiconductor (CMOS) with an area of 3 by 3
$\text{mm}^{2}$
. Simulation and experimental results are provided to validate the performance of the circuit, and a system efficiency above 93% is achieved for mismatch currents up to 3 A.