An integrated Boost Controller with MPPT for Submodule PV Applications

This paper introduces a boost controller with Maximum-Power-Point-Tracking for photovoltaic submodule applications. The controller IC operates in 300 kHz constant frequency peak-current-mode control over a wide input voltage range from 7 V - 24 V at output voltages up to 50 V. The proposed solution includes a low-side- and a bootstrapped high-side driver delivering up to 2 A of gate current for external power MOSFETs. The presented design can handle PV-input power levels of up to 144 W. For light solar insolation, the converter operates in DCM and uses a variable current pulse height to reduce the switching frequency and minimize losses. The peak efficiency measures 98.4 %, whereas a Maximum-Power-Point tracking efficiency larger than 99.9 % is achieved. The current sense is based on a 10mΩ low-side sense resistor. During DCM, the inductor current waveform is emulated for precise high-side turn-off. The circuit has been fabricated in a 0.18 μm BCD process.