- Balkan Journal of Electrical and Computer Engineering
- Vol: 8 Issue: 2
- Nested Miller Compensation Based Op-Amp Design for Piezoelectric Actuators
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 : 7 | Download : 2
Publication Date : 2020-04-30
Article Type : Research
Abstract :This study introduces the design of a practical three-stage operational amplifier (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 (V pp ) is implemented using commercial off-the-shelf (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 (GBP) and phase margin of 77°, and a common mode rejection ratio (CMRR) of 62dB.Keywords : Operational Amplifier, Stability, Piezoelectric, Actuator, Piezo Driver