Patent ID: 9306443
Filing Date: 2016-04-05
CPC Classification: H02J,H02M,Y02E

Claim Text:
1. A photovoltaic power circuit with auto zero calibration, for converting an input current and an input voltage generated by a photovoltaic device to an output current and an output voltage, the photovoltaic power circuit comprising: a trend judgment circuit having a storage mode and a comparison mode, the trend judgment circuit including: a power output control circuit which is coupled to the photovoltaic device at an input terminal and extracts electric energy at the input terminal to generate the output current and the output voltage at an output terminal, the power output control circuit adjusts the power conversion from the input terminal to the output terminal directly or indirectly according to an output from the trend judgment circuit so that the input current approaches an optimum current of the photovoltaic device, wherein the power trend indicator circuit includes: an analog multiplication circuit configured to operably receive a signal related to the input current and a signal related to the input voltage, and multiply them to obtain a signal related to power; a comparison and amplification circuit having an input terminal configured to operably receive the signal related to power; a capacitor having a high voltage terminal coupled to another input terminal of the comparison and amplification circuit; and a switch coupled between an output terminal of the comparison and amplification circuit and the high voltage terminal of the capacitor, the switch being controlled by a clock signal.