In many high voltage circuits, it often needs to shift the logic voltage
level to keep the circuit normal operation. In the class-D amplifier
circuitry, it needs to shift the voltage level of pulse width modulation
(PWM) signal to control the connecting of different power switches. In
other applications, such as a driver to drive amplifier of an audio
device, it also needs a level shift circuit to maintain the circuitry in
normal voltage operation. Therefore, this invention is to provide a novel
level shift circuit with high performance, low cost and low power
dissipation characteristics.