FREQUENCY-DIVIDER BASED ON MILLER INTEGRAL-TYPE SC ASTABLE-MULTIVIBRATOR

In a conventional-type astable multivibrator, the upper limit of the d ivision ratio for stable dividing operations is at most 1/20. In this paper, we propose and analyze a frequency divider based on the Miller integral-type switched capacitor (SC) astable multivibrator that maint ains stable operation even with a large dividing ratio. This divider h as a circuit configuration in which the state reversal occurs at a poi nt during the straight fall of the output voltage waveform of the Mill er integrator in a stepwise fashion. Therefore, the divider is not aff ected by either supply voltage or external noise. The dividing ratio c an be varied in a much larger range than that of the conventional type simply by changing the value of the capacitor. The mathematical formu la can be expressed simply with only circuit parameters. The computed values and the measured values agree well.Also, since no trigger gener ator is needed (as is the case with a conventional type), the dividers can be cascaded easily. The resultant dividing ratio is the product o f the individual dividing ratios. Further, by using two sets of modifi cations of this divider and by using one of them as the feedback circu it, a pulse number converter can be realized in which the ratio of the input pulse number and the output pulse number can be varied arbitrar ily.