A Low-Temperature-Drift High-Precision Band-Gap Reference Current Source

A Low-Temperature-Drift High-precision band-gap reference current source is developed. A reference voltage is generated by using the positive and negative characteristic of the crystal triode itself. The Power Supply Rejection Ratio is improved by using an operational amplifier which constitutes the degenerate loop. The temperature effect on the band-gap current is reduced by using an off chip resistor. The experiment results show that the temperature coefficient of the band-gap current source is 8.7×10-6/oC and it works well within 2.6V-4V power supply.