| 摘要 |
PURPOSE:To eliminate an influence of temperature drift by providing a duty ratio adjusting circuit for comparing a set value of a setting circuit and a counter value of a counting circuit for counting a clock pulse, and varying a duty ratio of an output pulse by the time required before both the values coincide with each other. CONSTITUTION:A clock pulse generated by a clock generating circuit 1 is frequency-divided by a clock frequency dividing circuit 2, and only in a period in which an output signal PLS waveform of a inverter circuit 6 is low, an output signal (C) of the same waveform as the clock pulse is outputted from an AND circuit 7, and inputted to a counter circuit 8. When a numerical value '3' is inputted in advance in an input terminal B of a comparing circuit 9, a coincidence signal is outputted at the time point of the third time of arise of the output pulse from the AND circuit 7. A flip-flop 12 in a flip-flop circuit 11 is set, when the PLS waveform becomes high, and reset, when a flip-flop 13 is set by the coincidence signal, therefore, the output signal of the flip-flop circuit 11 becomes a waveform (E) whose duty ratio is varied.
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