U2100B Datasheet, PDF (8/14 Pages) TEMIC Semiconductors – Timer Control for Triac and Relay

3.5 Tracking Time Pin 7
An internal RC oscillator with a following divider stage 1:2¹⁰ allows a very long and reproducible
tracking time.
The RC values for the required final time, t_t, can be calculated as follows:
R_t[Ω]
=
--------------^t-^t--^[--^s---^]---^×------¹---⁰----⁶--------------
1.6 × 1024 × C_t[µF]
C_t[µF ]
=
-------------^t--^t-^[--^s---^]---^×------¹---⁰----⁶-------------
1.6 × 1024 × R_t[Ω]
t_t[s]
=
C_-----t--[_-µ_----F_---]_----×_-----R_-----t--[_--Ω_----]_----×_------1_---._--6_----×_------1_----0_---2_---4_--
10⁶
3.6 Trigger Inputs Pins 5 and 6
Two AND-connected, identical inputs determine the trigger conditions of the monostable time
stages (Figure 3-6, Figure 3-7 on page 9), i.e., both inputs must be in position “ON” so that the
output is switched on. The tracking time starts after the trigger conditions have elapsed. The out-
put ON state is given until the tracking time has elapsed.
Input pin 5 is a simple comparator, whereas input pin 6 is designed as a window discriminator.
The noise suppression for t_ON = 40 ms prevents peak noise signals at the inputs which could
trigger the circuit.
At the same time, the retrigger function is delayed for a duration of 640 ms (t_OFF) to avoid noise
signal that may trigger the relay.
Figure 3-6. Trigger Condition, Pin 5
V₅
0
T₁ = 0.5 V_Ref
T₂ = 0.65 V_Ref
V_Ref
OFF
Hysteresis
ON
8 U2100B
4769C–INDCO–07/05