Nested Miller Compensation Based Op-Amp Design for Piezoelectric Actuators

Authors : Dincer GOKCEN, Mehmet Akif ÇELİK, Fatih Emre AYDOS

Pages : 186-192

Doi:10.17694/bajece.585798

View : 14 | Download : 9

Publication Date : 2020-04-30

Article Type : Research Paper

Abstract :This study introduces the design of a practical three-stage operational amplifier insert ignore into journalissuearticles values(op-amp); using nested Miller compensation, particularly for piezoelectric actuators. Driving a piezoelectric actuator represents a challenge in amplifier design due to its large capacitive nature. A stable piezo driver needs to be free of oscillations and phase lag. Direct feedback compensation using a conventional Miller capacitor is an effective method as long as the capacitance of the load is considerably close to the value of the Miller capacitor. However, using a large capacitor causes a decrease in the slew rate and gain bandwidth. To avoid this, our design focused on the utilization of nested Miller compensation technique. A prototype of the design working at 100V peak to peak voltage insert ignore into journalissuearticles values(V pp ); is implemented using commercial off-the-shelf insert ignore into journalissuearticles values(COTS); components. The measurements show the successful driving capability and step-response of the op-amp design. In the design, Widlar current source is also utilized for thermal stability and short circuit protection. According to simulation results, the proposed op-amp has a slew rate of 0.5 V/μs, an open loop gain of 90dB with 3MHz Gain Bandwidth Product insert ignore into journalissuearticles values(GBP); and phase margin of 77°, and a common mode rejection ratio insert ignore into journalissuearticles values(CMRR); of 62dB.
Keywords : Operational Amplifier, Stability, Piezoelectric, Actuator, Piezo Driver