SE555-SP Datasheet, PDF (11/18 Pages) Texas Instruments – QML CLASS V PRECISION TIMER

SE555-SP
www.ti.com
SGLS401 – FEBRUARY 2010
Missing-Pulse Detector
The circuit shown in Figure 16 can be used to detect a missing pulse or abnormally long spacing between
consecutive pulses in a train of pulses. The timing interval of the monostable circuit is retriggered continuously by
the input pulse train as long as the pulse spacing is less than the timing interval. A longer pulse spacing, missing
ÎÎÎÎÎ _{pulse, or terminated pulse train permits the timing interval to be completed, thereby generating an output pulse}
ÎÎÎÎÎ _{as shown in Figure 17.}
ÎÎÎÎÎ VCC (5 V to 15 V)
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ ₄
8
RL
RA
V_CC = 5 V
R_A = 1 kΩ
C = 0.1 µF
See Figure 15
Input
RESET
2
TRIG
VCC
3
OUT
Output
Input Voltage
7
DISCH
5
CONT
THRES ⁶
0.01 mF
GND
C
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ _{Output Voltage}
1
A5T3644
Capacitor Voltage
Figure 16. Circuit for Missing-Pulse Detector
Time − 0.1 ms/div
Figure 17. Completed Timing Waveforms for
Missing-Pulse Detector
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