| 摘要 |
PROBLEM TO BE SOLVED: To provide an adaptive bias generation circuit for a rail-to-rail operational amplifier which controls an amount of adaptive bias current more stably.SOLUTION: The adaptive bias generation circuit includes: an adder for adding a bias current and a given adaptive current to output a current resulting from the addition; an input differential pair circuit operative on the basis of the current from the adder in differentially amplifying differential input voltages to generate two corresponding currents; a current comparison circuit for comparing the two currents, selecting the lower current of the two currents, and outputting a current that is double the lower current; a current-voltage conversion circuit for subtracting a current that is a K multiple (0<K<1) of a current resulting from the addition of the two currents from a current that is a sum of the bias current, the adaptive current and the double current of the lower current, comparing a current resulting from the subtraction with the bias current, and converting a current resulting from the comparison to a voltage; and a current generation circuit for generating the adaptive current on the basis of the voltage from the current-voltage conversion circuit. |
