To prevent blunting of the waveform of triangular waves in a comparatively high oscillation frequency regarding an oscillation circuit outputting two triangular waves having the same amplitude and inverted phase and a PWM circuit using the oscillation circuit.
A capacity 3 is charged and discharged by a charge pump circuit 2 controlled by a Schmitt circuit 1, and a voltage integrated by a two-output differential amplifier 6 is fed back positively to an input to the Schmitt circuit 1, thus outputting two triangular waves having the same amplitude and the inverted phase. A triangular-wave generating circuit has no effect of wiring capacity and input capacity connected because the output stage is of low-output impedance being composed of the differential amplifier, and the blunting of triangular waves is prevented for integrally operating the differential amplifier.
Toshiji Sasahara
Yohei Harada