Translinear slew boost circuit for operational amplifier

A method of improving the slew rate of an amplifier is described where a differential pair of transistors receives a differential first control signal and second control signal. The tail current for the transistors is provided by a tail current regulator. The same control signals are applied to a slew boost controller, whose output increases as the differential between the control signals increase. The tail current regulator generates a bias signal that sets a minimum tail current. The tail current is controlled to be the minimum tail current until the slew boost output signal exceeds a threshold, whereupon the tail current increases in response to an increasing differential between the control signals. Common mode rejection is not adversely affected by the slew boost controller generating a slightly varying current under common mode conditions due to the minimum tail current.