单电容米勒补偿三级运放设计

A Three-Stage Amplifier with Single-Miller Capacitor Compensation

为了满足低压电路的工作要求,我们设计了一种新型的三级运放。该运放采用单电容米勒补偿与交叉多径嵌套补偿结合的方法,利用前馈通路在左半平面形成的零点来补偿其在主通路中的极点。通过使用TSMC 0.18μm工艺仿真。仿真结果表明:该运放能够获得113 dB的增益,有着87°的相位裕度,在1.8 V电源电压和120 pF负债的情况下,整体功耗只有0.534 mW。由此可见,这种新型的补偿方式能够有效地对运放进行补偿,并且使运放获得较高的增益以及较大相位裕度。

A three-stage amplifier with a new compensation method was designed so as to meet the needs of low voltage circuits. This new compensation method combines the single Miller-capacitor compensation and the crossed feedforward reversed nested Miller compensation together, using the zeros formed by the feedforward path to compensate the poles in the main path. Using TSMC 0. 18um CMOS technology, the circuit has a DC gain about 113 dB, a PM of 87 degree and the power dissipation is just 0. 534 mW with a 120 pF capacitor load. The compensation is effective and the op-amp has a great gain and a large PM.