A photovoltaic circuit for supplying an output current (10; 60), the photovoltaic circuit (1; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 16; 17; 18; 19) being coupled to a tank module and a photovoltaic transformation module (50; 51; 52), the photovoltaic transformation module (50; 51; 52) being configured to receive an optical energy and transform the optical energy into a current (12i; 12n), the photovoltaic circuit being configured to receive and modulate the current (12i; 12n) as the output current (10; 60) supplied to the tank module, the tank module generating a tank status signal, the photovoltaic circuit comprising: a first process module, being coupled to the tank module and the photovoltaic transformation module (50; 51; 52), and configured to generate a first divided current (320; 630) in response to the current (12i; 12n) and modulate the first divided current (320; 630) to generate a first modulation current; a plurality of second process modules, being connected to the first process module in parallel and coupled to the tank module and the photovoltaic transformation module (50; 51; 52), and configured to generate a plurality of second divided currents in response to the current (12i; 12n) and modulate the second modulation currents to generate the second modulation currents; and a first control module, being connected to the first process module, the second process modules and the tank module, configured to generate a charge protection signal which is an impulse signal having an modulated duty in response to the tank status signal of the tank module, control and average magnitude of the output current (10; 60) by modulating the modulated duty, and generate a control signal (150; 152; 154; 156; 158) to the first process module and the second process modules in response to the first divided current (320; 630), the first modulation current, a last output current (124; 324; 634), the charge protection signal, and an MPPT way; wherein the first process module outputs the first modulation current as the output current (10; 60) supplied to the tank module in response to the charge protection signal, the second process modules output the second modulation currents as the output current (10; 60) supplied to the tank module in response to the charge protection signal, and the first modulation current and the second modulation currents are outputted as the output current (10; 60) supplied to the tank module in a interlaced way. a first process module, being coupled to the tank module and the photovoltaic transformation module (50; 51; 52), and configured to generate a first divided current (320; 630) in response to the current (12i; 12n) and modulate the first divided current (320; 630) to generate a first modulation current; a plurality of second process modules, being connected to the first process module in parallel and coupled to the tank module and the photovoltaic transformation module (50; 51; 52), and configured to generate a plurality of second divided currents in response to the current (12i; 12n) and modulate the second modulation currents to generate the second modulation currents; and a first control module, being connected to the first process module, the second process modules and the tank module, configured to generate a charge protection signal which is an impulse signal having an modulated duty in response to the tank status signal of the tank module, control and average magnitude of the output current (10; 60) by modulating the modulated duty, and generate a control signal (150; 152; 154; 156; 158) to the first process module and the second process modules in response to the first divided current (320; 630), the first modulation current, a last output current (124; 324; 634), the charge protection signal, and an MPPT way; wherein the first process module outputs the first modulation current as the output current (10; 60) supplied to the tank module in response to the charge protection signal, the second process modules output the second modulation currents as the output current (10; 60) supplied to the tank module in response to the charge protection signal, and the first modulation current and the second modulation currents are outputted as the output current (10; 60) supplied to the tank module in a interlaced way.