Additionally, according to the above described preferred embodiment, the ramp signal Ramp3 is generated in syn chroniZation With the pulse signal from the oscillator 2.
HoWever, the ramp signal Ramp3 may be drop to the ground level until the reception of the next set pulse, When a reset pulse is generated. This operation is implemented as fol loWs: the output of the comparator 12 is input to the ramp signal generating circuit 3, Which generates its output based on the input signal and the pulse signal from the oscillator 2. Such a configuration contributes to the capability for
preventing a malfunction.