Electronic circuit for producing a reference current independent of temperature and supply voltage

A current supply circuit, comprising a first current supply sub-circuit with a negative temperature coefficient, and a second current supply sub-circuit with a positive temperature coefficient,

• wherein the first current supply sub-circuit comprises:
• a first bipolar transistor, the emitter terminal of which is connected through a first resistor to a first voltage supply rail,
• wherein the second current supply sub-circuit comprises:
• second, third, fourth and fifth bipolar transistors, the bases of the second and third transistors being connected together, and to the collector terminal of the third transistor, the collector terminal of the third transistor being connected to a second voltage supply rail through a second resistor, the emitter of the second transistor being connected to the collector of the fourth transistor, and to the base of the fifth transistor, the emitter of the third transistor being connected to the collector of the fifth transistor, and to the base of the fourth transistor, the emitter of the fourth transistor being connected to the first voltage supply rail through a third resistor, and the emitter of the fifth transistor also being connected to the first voltage supply rail;
• the current supply circuit further comprising means for summing the currents through the first transistor and the second transistor to produce an output current;
• and
• the base of the second transistor being connected to the base of the first transistor to provide a bias voltage therefor.