Efficiency of the class B-CE and class B-CC high-voltage wideband amplifiers with a capacitive load

Abstract

The design of high-voltage wideband amplifiers for excitation of ultrasonic actuators and transmitters has problem with limited slew-rate for full range excitation. This problem is connected with value of total power dissipation of transistors, especially for the advantageous class B stage with common emitters. The power dissipation of transistor is substantially dependent on phase shift of capacitive load especially for high frequency range. This paper solves the dependency of the power dissipation and efficiency on phase shift of load and by this way it enables to solve optimum solution of problems connected with this effect. Especially, the maximum slew-rate can be attained by optimum choose of transistors.

Power Parameters and Efficiency of Class B Audio Amplifiers in Real-World Scenario

“…There is possibility to decrease the dissipated power P D and to increase the efficiency  of the class B power amplifiers via loudspeaker system's impedance compensation using an appropriate Zobel network [14,15]. Thus the impedance profile of the amplifier's load will have a (close to) resistive nature (in the frequency band of operation) and this is proved to be the optimum case of operation in the light of amplifier efficiency [16]. Also, this approach is extremely effective in reducing of the peak instantaneous power dissipation of the amplifier [4].…”