U2100B View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

U2100B

Timer Control for Triac and Relay

Atmel Corporation 

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, tt, can be calculated as follows:

Rt[Ω]

=

--------------t-t--[--s---]---×------1---0----6--------------

1.6 × 1024 × Ct[µF]

Ct[µF ]

=

-------------t--t-[--s---]---×------1---0----6-------------

1.6 × 1024 × Rt[Ω]

tt[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 tON = 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 (tOFF) to avoid noise

signal that may trigger the relay.

Figure 3-6. Trigger Condition, Pin 5

V5

0

T1 = 0.5 VRef

T2 = 0.65 VRef

VRef

OFF

Hysteresis

ON

8 U2100B

4769C–INDCO–07/05

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