A photovoltaic circuit configured to supply an output current to a tank module is provided. The photovoltaic circuit comprises a photovoltaic transformation module, a first process module, a plurality of second process modules, and a first control module. The process modules are connected to each other in parallel. The process modules in the parallel connection are connected to the photovoltaic transformation module and the tank module in series. The first control module is connected to the first process module and generates a control signal to the process modules in response to a divided current, a modulation current, and a last output current generated by the first process module. Thereby, the process modules interlacedly output the corresponding modulation current as the output current supplied to the energy reserve module.