TEA2029 STMICROELECTRONICS [STMicroelectronics], TEA2029 Datasheet - Page 21

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

V.5.2.2 - Low-pass filter f(p)
The horizontal phase-shift adjustment is taken into
account : see Figure 39
- Filter V = f(i) transfer characteristic is given as :
Figure 39
In Dynamic Mode
- V = Zi
The network behaves as a first order low-pass filter
whose cut-off frequency at -3dB is : f
Filter component values
- R = 470k and C = 22nF
- R
V.5.2.3 - Phase modulator
This is built around a comparator which converts
the filter voltage to a rectangular waveform such
that its rising edge phase, variable as a function of
filter voltage ”V”, will trigger the line transistor turn-
off control circuitry.
The conversion gain is determined by the slope of
the line saw-tooth applied to comparator.
Horizontal
V = Zi +
Where :
Where :
Phase
Adjust
Z = R
R
R’ = R
In practice, (K
IN
F
out adjustment
IN
= R’ . C : Filter time constant
3db
= 25M , I
, I
IN
IN
= 15.7Hz with adjustment and 0.3Hz with-
IN
Z
R
P
: modulator input characteristics
f(p) =
// R //
V
// R (R >> Potentiometer P)
Comparator
+
CC
K V
IN
KV
V
2
i
C p
i
CC
= 0.65 A (base input current)
= Z(p) =
CC
1
R
[0,1]) V
- Z I
16
IN
C
CC
1
V
R
= 12V
p
Phase Modulator
-3dB
R
IN
=
2 R C
I
1
IN
Figure 40
Figure 41
Transfer characteristic is given by :
Let’s consider the delay interval between ”t
and the reference time ”t
where t
t
Where :
- t1 = 4.3 s
- t
- t
- t
V.5.2.4 - Line flip-flop (TEA2028 only for TEA2029
refer to Section VII.6)
It generates a constant duration rectangular signal
used to turn-off the line transistor. It is triggered by
the rising-edge of the phase comparator output
voltage and reset after capacitor on pin 1 is
charged.
TEA2028 - TEA2029 APPLICATION NOTE
OUT
Line Output
Signal (Pin 10)
Line Flyback
(LF)
t
Reset for V
logic block and are synchronized on line sync
Delay between leading edge of output signal -
Pin 10 - and the middle of line flyback
d
H
OUT
OUT
V
= 2 to 15 s
= 64 s
- t
- t
IN
=
V
OUT
IN
13
= t
V
t
= B.V + t
(t)
13
is the middle of line flyback :
2
13
3.5V
13
+ t
V’
V
= B = 16.4 s/V therefore t
V
and V are signals coming from line
0
OUT
2
T
d
16
t
10
+ t
1
V
t
IN( 2)
13
= constant
d
1
- 59.7 s
- t
(t)
V
H
IN
t
”
2
T
= f(v)
H
t’
V’
OUT
OUT
t’
OUT
2
t
t
D
IN
= B.V
t
OUT
= 0
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OUT
”