Browse Prior Art Database

High-Speed, High-Voltage, Coaxial Line Driving Amplifier

IP.com Disclosure Number: IPCOM000100499D
Original Publication Date: 1990-Apr-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Ho, CT: AUTHOR [+2]

Abstract

Disclosed is a circuit to extend the output voltage and current ranges of a high-speed amplifier without significant loss of bandwidth. High- speed, high-current amplifiers typically require very high power as high power devices have larger capacitances than lower power devices and they are slower. A high voltage amplifier is more sensitive to Miller capacitive effects due to the larger voltage swings at the output stages compared to a low voltage amplifier. The high Miller capacitance reduces the output slew rate (transient speed) and therefore reduces the amplifier bandwidth.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

High-Speed, High-Voltage, Coaxial Line Driving Amplifier

       Disclosed is a circuit to extend the output voltage and
current ranges of a high-speed amplifier without significant loss of
bandwidth.  High- speed, high-current amplifiers typically require
very high power as high power devices have larger capacitances than
lower power devices and they are slower.  A high voltage amplifier is
more sensitive to Miller capacitive effects due to the larger voltage
swings at the output stages compared to a low voltage amplifier.  The
high Miller capacitance reduces the output slew rate (transient
speed) and therefore reduces the amplifier bandwidth.

      The circuit described produces a stable (large phase margin),
high-speed, high-voltage, high-current, and high-accuracy amplifier.
This is achieved by adhering to the following strategy.  A minimal
number of components is used to reduce loop propagation delays that
cause instability.  Current steering (current transfer loop) provides
signal amplification without large RC phase shifts which cause
instability at high frequencies.  All amplifying transistors are used
in a common base configuration which effectively avoids Miller
capacitive effects and generates sufficient power to overcome the
capacitive loading effects of the emitter follower output stage.
Negative feedback is used to reduce distortion while enhancing DC
accuracy of the circuit.

      Referring to the figure on the next page, the high-speed op...