Current source circuit

The invention relates to a current source circuit which comprises a node, a bias circuit, a load circuit and a current mirror circuit, wherein the node has specific voltage; the bias circuit is used for biasing the voltage of the node into first reference voltage; and the load circuit is used for providing an equivalent resistor crossing between the node and second reference voltage so as to generate reference current. The load circuit comprises a resistor and a metallic oxide semiconductor field effect transistor, wherein the resistor has a first temperature coefficient, is controlled by voltage to conduct and operated in a linear area and forms a transistor resistor which is connected with the resistor in series; the transistor resistor has a second temperature coefficient; and the temperature coefficient of the equivalent resistor is correlate with the first temperature coefficient and the second temperature coefficient. The current mirror circuit is used for receiving the reference current and mapping and