An Event Triggered-FOCV MPP Technique with Irradiance Change Detection Block for Next Generation EH-Converters

An Event Triggerred — Fractional Open Circuit Voltage Maximum Power Point Tracking (ET-FOCV MPPT) technique is introduced for irradiance change aware open-circuiting in FOCV systems. The ET-FOCV scheme is implemented using a novel Irradiance Change Detection (ICD) block which is based on gradient based current sensing technique. By avoiding the periodic open circuiting in the absence of irradiance change, this technique extracts more energy than the conventional FOCV systems. The proposed ICD block can operate from 10 Hz to 100 kHz system clock frequencies targeting micro scale energy harvesting systems. With the ICD block and ET-FOCV technique, the proposed solar energy harvesting system harvests energy from input power level of 200 µW to 20 mW and input voltage level of 100 mV to 1.5 V and charges a battery to 3.3 V by boost operation. The entire system is implemented in standard 180 nm CMOS technology and the extracted results validate the system performance.