Figure 21 shows one of the pulse width modulated signal. When the triangle
wave and the audio signal intersect a pulse is formed. Due to the delay of the
operational amplifier the pulse is offset from where the triangle and audio signal
intersect. The triangle in this figure is the actual triangle wave generated by the
XR2206 at 200 kHz.
c) Pulse Width Modulation with Dead Time
To avoid having simultaneous conduction of both NMOS’s a non-overlapping
pulse circuit had to be design with adjustable dead time. The non-overlapping pulses
were generated by comparing the audio signal to the generated triangle wave and
also to a DC offset triangle wave, which would introduce the desired dead time by
increasing the DC voltage. This gave us the two different pulses and has an
adjustable dead time, by adjusting the DC offset we are able to change the dead
Figure