CLASS D AMPLIFIERS INCLUDING TRANSITION ZONE MODULATION

摘要

Class D amplifiers and methods dynamically modulate the transition zone of a square wave as a function of the input signal. Stated differently, the slew rate of the square wave is dynamically modulated as a function of the input signal. Stated in yet another way, at least one of the rise and fall times of the square wave is dynamically modulated as a function of the input signal. By dynamically modulating the transition zone of the square wave as a function of the input signal, a trapezoidal wave is produced, at least one of the rise and fall times of which are dynamically modulated as a function of the input signal. The trapezoidal wave need not have dead zones. This can reduce and preferably minimize switching losses. The slow rise and fall transition zone rates can also reduce and preferably minimize spurious switching noise at zero and low level modulation. Furthermore, damping network and diode losses may be reduced. Finally, very small differences of slew rate modulation may be produced, to thereby accurately quantify small signals. Improved class D amplifier circuits and methods are thereby provided.