Constant current circuit and constant current system with same

The utility model discloses a constant current circuit comprising a voltage reducing module and a current generating module. The voltage reducing module is connected to the power supply and is used for reducing the voltage output by the power supply and generating a first voltage signal; the current generating module is connected to the voltage reducing module and is used for generating the constant current according to the first voltage signal; the current generating module comprises a constant current sub module, and the constant current sub module adjusts the output current according to the change of the temperature to generate the constant current. According to the constant current circuit, the accuracy of the constant current is high, the linear adjustment is fine, structure is simple, and cost is low. The utility model further discloses a constant current system with the constant current circuit.