Linear power amplifier with a pulse density modulated switching power supply

摘要

A linear power amplifier having a pulse density modulated switching power supply comprising: power supply means for connection to a source of electrical power and adapted to provide (i) a first, relatively high DC voltage, and (ii) a second, relatively low DC voltage; voltage amplifying means for connection to a signal source and adapted to amplify a first, relatively low voltage signal received from the signal source into a second, relatively high voltage signal; current amplifying means connected to the voltage amplifying means and adapted to increase the current flow of the second, relatively high voltage signal, as needed, in order to properly drive a load, wherein the current amplifying means are normally powered by the second, relatively low DC voltage supplied by the power supply means; and pulse generating means connected to the line carrying the second, relatively high voltage signal to the load, and to the line supplying power to the current amplifying means, the pulse generating means being adapted to (i) compare the instantaneous voltage amplitude of the second, relatively high voltage signal with the level of the voltage powering the current amplifying means, and (ii) provide fixed duration pulses, at the first, relatively high DC voltage, to power the current amplifying means whenever, and so long as, the voltage amplitude of the second relatively high voltage signal rises high enough relative to the level of the voltage powering the current amplifying means to cause the current amplifying means to approach saturation.