CA1244894A — Low voltage class b amplifier with low value decoupling capacitors

USPTO Abstract

TITLE: LOW VOLTAGE CLASS B AMPLIFIER WITH LOW VALUE DECOUPLING CAPACITORS ABSTRACT OF THE DISCLOSURE A class B push-pull integrated circuit suitable for low voltage operation, having two symmetrical halves. Each half circuit has first and second opposite conductivity type transistors having their collectors connected together to the base of a class B driver trans-istor, the collector of which drives the base of an out-put transistor. An AC input signal is divided into in-phase and anti-phase components one of which is applied to the base of each first transistor. An AC feedback loop extends from the collector of the fourth transistor through a voltage divider and level shifter to the base of the second transistor. A DC feedback loop extends from the base of the fourth transistor through a fifth transistor to the base of the second transistor. De-coupling capacitors extend from the bases of the fifth transistors and through a diode to ground. The arrange-ment allows use of small decoupling capacitors, and a current forced through the diode eliminates turn-on de-lay.