This paper presents the design of a CMOS programmable slew rate operational amplifier based upon a newly proposed concept, that is a switched parallel current subtraction circuit with adaptive biasing technique. By utilizing the newly designed circuit, it was proven that slew rate was linearly controlled and power dissipation was optimized. If the programmable slew rate amplifier is employed into mixed signal system, it can furnish the convenience of timing control and optimized power dissipation. Simulated data showed the slew rate ranging from 5. 83V/$mu$s to 41.4V/$mu$s, power dissipation ranging from 1.13mW to 4.1mW, and the other circuit performance parameters were proven to be comparable with those of a conventional operational amplifier.