SCT1555 Datasheet, PDF (8/10 Pages) Zetex Semiconductors – PRECISION SINGLE CELL TIMER

ZSCT1555
Figure 5 shows the monostable mode used as
a pulse width modulator. Here the trigger pin
is supplied with a continuous pulse train, the
resulting output pulse width is modulated by
a signal applied to the control pin.
Astable operation
The configuration of Figure 7 produces a free
running multivibrator circuit whose frequency
is independent of supply voltage. The ratio of
resistors RA and RB precisely sets the circuit
duty cycle. The capacitor is charged and
discharged between thresholds at 0.2V_CC and
0.8V_CC. Oscillation frequency (f) and duty cycle
(d) can be calculated using the following
equations:-
f = 0.62/(RA + 2RB)C_T
d = RB /(RA + 2RB)
Figure 5
Figure 6 shows typical waveform examples.
Figure 7
Figure 8 shows the waveforms generated in
this mode of operation.
Figure 6
Figure 8
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