opamp 设计教程 I

Lecture 120 – Compensation of Op Amps-I (1/30/02) Page 120-1

ECE 6412 - Analog Integrated Circuit Design - II © P.E. Allen - 2002

LECTURE 120 – COMPENSATION OF OP AMPS - I

(READING: GHLM – 425-434 and 624-638, AH – 249-260)

INTRODUCTION

The objective of this presentation is to present the principles of compensating two-stage

op amps.

Outline

ECE 6412 - Analog Integrated Circuit Design - II © P.E. Allen - 2002

Objective

Objective of compensation is to achieve stable operation when negative feedback is

applied around the op amp.

Types of Compensation

1. Miller - Use of a capacitor feeding back around a high-gain, inverting stage.

• Miller capacitor only

• Miller capacitor with an unity-gain buffer to block the forward path through the

compensation capacitor. Can eliminate the RHP zero.