Low temperature coefficient reference source circuit

The invention relates to a low temperature coefficient reference source circuit, which is characterized by comprising resistors R0, R1, R2, R3 and R4 with changeable resistances, field-effect tubes M1, M2 and M3, an operation amplifier and a diode; the reference source circuit uses a positive temperature coefficient of delta VBE as a temperature sensor. A band gap circuit is provided with a segmentation module capable of changing the resistances of the resistors according to temperature segments, when an environment temperature changes, the delta VBE changes, then a comparator in a segmentation judging module compares the delta VBE with a reference voltage to determine an interval number for dividing the environment temperature, finally, the resistance of a corresponding proportional resistor is adjusted according to an output outcome of the comparator. Compared with prior art, the work temperature of the circuit is segmented and the resistances are changed to remove voltage deviation, and the influence of the temperature coefficient to the output voltage is reduced furthest.