TEA2029 STMICROELECTRONICS [STMicroelectronics], TEA2029 Datasheet - Page 22

• Manufacturer Part Number: TEA2029
• Description: APPLICATION NOTE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

TEA2028 - TEA2029 APPLICATION NOTE
A. BLOCK DIAGRAM
”V’
capacitor ”C1” to be charged by current ”I
ered through current generator. The voltage across
capacitor begins rising until it reaches ”V
this time, comparator ”C” is triggered, the output of
which will in turn reset the flip-flop. The capacitor
”C” is consequently discharged by current I
Figure 42
B. T10 CALCULATION (see Figure 43)
”I
with R14 = 3.32k , C1 = 3.3nF
- T
-
C. 16 s WINDOW
This window is generated by the line logic circuitry
and sets the maximum phase variations of the
output signal ”V
Also, for protection purposes, should ”V
equal ”0”, the output signal will be always present
and have a maximum phase shift of 16 s with
respect to the falling-edge of the line saw-tooth.
D. AUTO-SET TO ”1”
To provide protection, this function will trigger the
f lip -flop if the modulato r is d isa bled, i. e.
V
22/46
Window
V’
C
16
to device
OUT
” is a fraction of ”I
OUT
T
10
has a maximum dispersion of 3% from device
> V
10
is independent from temperature and V
” will set the flip-flop thereby allowing the
=
13(MAX)
16 s
t’
OUT
I
C
T
R14 C1 = 2.64 R14 C1
10
=
.
I
=
10
REF
C
C1
”.
A S
&
Auto-Set
Signal
REF
=
I
C
” on pin 14
V
V
V
V
REF
1
REF
1
R14
1
144 A
=
1
I
C1 V
C
C1
S
R
= 144 A
+
I
Q
Q
C
I
380 A
REF
T
D
t’
10
OUT
V
= 29 s
T
1 0
16
10
” voltage
To Output
Stage
C
REF
” deliv-
D
CC
- I
”. At
C
.
Figure 43
E. MAXIMUM ”T10” VALUE AS A FUNCTION
OF ”C1”
T
T
For normal operation, C1 value has to be chosen
between 2.3nF and 4.6nF.
If Pin 1 is grounded, output signal (Pin 10) is
inhibited and goes high.
V.5.2.5 - Line output stage & inhibitions
Figure 44
10 (Min.)
10 (Max.)
Monostable
Logic 1 for
V
Logic 1 for
Security at Pin 28
Q
C C
Window
Auto-Set
: 16 s (window) + 4 s (auto set) = 20 s
: for
< 6V
Set
V’
OUT
C1
T
T
16 s
V
10 (Max.)
V
1 0
1
10
0
(Min.)
1
C1 V
3V
Line Flyback
16 s
I
D
Inhibition
T
Input
1 2
10
= 2.3nF
= 40 s
T
I
1
REF
LF
T
C
10
10
4 s
+
C1 V
I
1 0
10
C1
I
6
Maximum
Variation
C
V
Phase
Ground
REF
+
C C
Power
(Max.)
(1.26V)
R
Output
V
L
REF
Line ”DRIVE”
= 4.6nF
64 s
t
T
To
1 0