A new design for improving the Slew rate of Low Power Two-Stage Operational Amplifier with Single-Ended

Low power single-ended operational amplifier with high slow rate in new technologies due to decreasing dimensionality and supply voltage level has attracted many researchers in recent years. These researchers often used auxiliary circuit for increasing the charging and discharging currents of load and compensation capacitances. Nevertheless, many of these methods are not able to improve the positive and negative slew rates symmetrically, and usually lead to increase power consumption and circuit dimensionality and complexity. Therefore, in this research, an auxiliary circuit in TSMC 0.18 µm technology is provided for improving the slow rate in two-stage operational amplifier with single-ended output. This proposed circuit under a 2 pF load capacitance and a 1.8 V supply voltage could increase the positive and negative slew rates to up 8.87 and 22.67 times, respectively, which lead to significant symmetry in the positive and negative slew rates. Besides, this auxiliary circuit had not significant effects on the gain, bandwidth, unity gain frequency and phase margin of operational amplifier, and only increased the power consumption by as much as 1.5% (10.59 µW). Therefore, this circuit can be a good suggestion to improve slew-rate parameter in the low power operational amplifiers with single-ended output.