TEA1007 Temic Semiconductors (acquired by ATMEL Corporation), TEA1007 Datasheet - Page 3

• Manufacturer Part Number: TEA1007
• Description: Simple Phase Control Circuit
• Manufacturer: Temic Semiconductors (acquired by ATMEL Corporation)

TELEFUNKEN Semiconductors
Rev. A1, 28-May-96
In indication as to whether load current is flowing or not
is provided by the triac itself. When the triac is ignited,
the voltage at electrode H
value of the mains voltage to approximately 1.5 V, the
value of the forward voltage of the triac. When the load
current drops below the hold current of the triac towards
the end of the half-cycle, V
taneous value of the mains voltage. The current detector
with its input at Pin 4 now controls this triac voltage and
blocks the pulse generator via G
reference voltage as long as the triac is conducting. As, in
the case of a resistive load, the triac may be extinguished
shortly before the zero transition of the mains voltage –
when the load current drops below the hold current – the
RS flip-flop must prevent any possible second ignition
pulse from being generated.
Figure 4. Functional diagram for resistive load and
1
H1
drops from the instantaneous
again returns to the instan-
1
and S
1
by increasing the
95 11359
a
min
Additional Function
An internal supply voltage control circuit insures that
output pulses can be generated only when the supply
voltage required for operation of all logic functions is
available.
Series resistance R
I
I
I
I
I
Determination of Gate Series
Resistance, Firing Current and Pulse
Width
Firing current requirement depends upon the triac used
which can be regulated with series resistance as given
below:
R
whereas:
V
I
I
T
t
C ö
p
tot
tot
S
P
x
G
P
G max
G
= Current requirement of other peripheral components
= Current requirement of the lC
= Average current requirement of the triggering pulses
= I
= Total current consumption
I
t
R
P
P
S
[
1 max
[
+
=Triac’s gate voltage
=Triac’s gate current
=Gate current requirement – average
=Period duration of mains frequency
=(firing) pulse width
=Ramp capacitor
+ I
12.5 V – V
8
I
T
G
nF
+
P
m
+ I
s
0.85
I
t
x
p
G max
whereas
C
1
ö
can be calculated approx. as follows:
V
G max
M min
2
– V
– 110
I
tot
TEA1007
S max
W
3 (8)