tda8433 NXP Semiconductors, tda8433 Datasheet - Page 18

• Manufacturer Part Number: tda8433
• Description: Deflection Processor For Computer Controlled Tv Receivers
• Manufacturer: NXP Semiconductors

Philips Semiconductors
APPLICATION INFORMATION
The formulae from which the typical
vertical drive and typical E-W drive
waveforms are generated are given
in the following sub-paragraphs. For
this purpose a typical application
diagram for the vertical drive stage
is assumed to be as illustrated in
Fig.7. Pin 20 is the vertical drive
output which drives an inverting
power amplifier. The feedback
network, R1 to R4 and C1 and C2,
has two functions;
For this typical application the
formula for the vertical scan
waveform refers to the voltage at
pin 21. The formula for the E-W
drive waveform refers to the voltage
at pin 19.
All DAC variables that control the
vertical and E-W drive waveforms
are normalized. Each DAC is
defined as having a control range
between 0 and 1. The 0
corresponds to a register value of
HEX00 and the 1 to a maximum
value of HEX1F (for a 5-bit DAC) or
HEX3F (for a 6-bit DAC).
August 1991
To transfer the voltage on the
feedback pin (pin 21) to a voltage
across the feedback resistor R1
To stabilize the voltage across C1
at a fixed value.
Deflection processor for computer
controlled TV receivers
Table 4 DAC variables
Further definitions
V
V
V
and 1/7 V
V
V
If the Trapezium function (T) compensates for the internal offset voltage then the
actual formula for Z will simplify to:
Z = 1 + 2V
Since 0 V
that: 1
a: Picture height
y: V-linearity
s: V-S correction
d: V-shift
v: V-compensation
w: Picture width
p: E-W parabola
c: E-W corner
t: Trapezium
h: H-compensation
A = 0.80 (a + 2)/3
Y = 0.17 y
S = 0.42 s
D = 2.4
W = 0.16 w
SAW
CC
EHT
OFF
int
= Internal reference voltage of 7.1 V (also on pin 4)
= supply voltage applied to pin 12.
= EHT compensation voltage applied to pin 1, normally between 1/2 V
= Internal offset voltage.
= Instantaneous sawtooth voltage (pin 22) normally; 0 < V
CC
Z
0.7 d volts
saw
V
.
SAW
1.
/V
int
18
7.1 V, this is simply a negative going sawtooth and it follows
0
0
0
0
0
0
0
0
0
0
a
y
s
d
v
w
p
c
t
h
1
P = 0.55 p
C = 0.38 c
T = 0.32 (1 + 2t) volts
E = (V
Z = 1 + 2 x (V
1
1
1
1
1
1
1
1
1
CC
64 steps (6 bits)
64 steps (6 bits)
64 steps (6 bits)
64 steps (6 bits)
32 steps (5 bits)
64 steps (6 bits)
64 steps (6 bits)
64 steps (6 bits)
64 steps (6 bits)
32 steps (5 bits)
/ 2
V
saw
EHT
) / 42
T) V
Product specification
int
TDA8433
saw
7.1 V;
CC