Frequency Compensation¶

Introduction to Frequency Compensation

After the bandwidth of a negative feedback amplifier has been designed, the poles of the transfer are not necessarily in the desired positions.

Presentation

The presentation “Introduction to Frequency Compensation defines the term frequency compensation and presents strategies and methods for frequency compensation.

Video

Introduction to frequency compensation (9:01)

Study

Chapter 12.1

The Phantom Zero

Phantom zero frequency compensation is the most powerful frequency compensation technique.

Presentation

The presentation “Frequency Compensation: the Phantom Zero introduces the concept of the phantom zero.

Video

Phantom Zeros (0:00 - 4:30)

Study

Chapter 12.2.1

Phantom Zero Compensation of a 2nd-order System

Presentation

The presentation “Frequency Compensation: the Phantom Zero Compensation of a 2nd-order System applies the concept of phantom zero frequency compensation to the compensation of a second order system.

Video

Phantom Zeros (4:30 - 18:20)

Study

Chapter 12.2.2

Implementation of Phantom Zeros

Practical implementation of phantom zeros can be accomplishes in two ways:

1. Active phantom zeros
2. Passive phantom zeros

Active implementation requires the use of active differetiating circuits in the feedback loop of the amplifier.

Passive compensation requires the insertion of loop gain zeros in:

1. The feedback network
2. Coupling networks between the signal source and the input of the amplifier
3. Coupling networks between the output of the amplifier and the load.

Such passive zeros are called effective if:

1. They do not significantly affect the initial pole positions (before compensation) of the loop gain
2. They do not introduce new dominant poles

This is usually the case if, before compensation, these feedback networks or coupling networks introduce a large attenuation in the loop gain at the phantom zero frequency.

Presentation

The presentation “Implementation of Phantom Zeros presents passive implementation techniques for phantom zeros and discusses the effectiveness of the frequency compensation.

Study

Chapter 12.2.4, 12.2.5, 12.2.6

Examples Phantom Zero Frequency Compensation

Presentation

The presentation “Examples Phantom Zero Compensation presents Examples 11.8, 12.8 and 12.9.

Video

Examples of implementation of phantom zeros (15:23)

Study

Examples 11.8, 12.8 and 12.9

Phantom zero compensation and interaction with other performance aspects

Presentation

The presentation “Phantom zero compensation and interaction with other performance aspects briefly discusses the interaction between frequency compensation with phantom zeros and other performance aspects, such as, noise, bandwidth, weak distortion, energy storage, power dissipation and overdrive recovery.

Study

Chapter 12.2.8.