IMPROVED EXPONENTIAL CURRENT GENERATOR AND METHOD

摘要

An apparatus and method of generating a current pair Ip, Im where the ratio of the pair is exponentially related to a control signal, and where either Ip or Im is greater than or less than a minimum or maximum value. The apparatus includes a feedback correction circuit used to sense the value of Im or Ip. The correction circuit supplies a boost current Iboost when the sensed value of Ip or Im is less than or greater than the minimum or maximum value. Iboost is preferably maintained proportional to the difference of the desired value and Ip or Im.