tda8359j-n2 NXP Semiconductors, tda8359j-n2 Datasheet - Page 11

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tda8359j-n2

Manufacturer Part Number
tda8359j-n2
Description
Full Bridge Vertical Deflection Output Circuit In Lvdmos
Manufacturer
NXP Semiconductors
Datasheet
Philips Semiconductors
Flyback supply voltage calculation
If the flyback time is known, the required flyback supply
voltage can be calculated by the simplified formula:
where:
The flyback supply voltage calculated this way is
approximately 5% to 10% higher than required.
Calculation of the power dissipation of the vertical
output stage
The IC total power dissipation is given by the formula:
P
The power to be supplied is given by the formula:
In this formula 0.3 [W] represents the average value of the
losses in the flyback supply.
The average external load power dissipation in the
deflection coil and the measuring resistor is given by the
formula:
Example
Table 1 Application values
2002 Jan 21
V
x
P
P
I
I
L
R
R
f
t
coil(peak)
coil(p-p)
vert
FB
tot
FB
sup
L
coil
coil
M
Full bridge vertical deflection output circuit
in LVDMOS
=
= P
=
SYMBOL
-------------------------- -
R
=
=
------------------------------- -
coil
I
sup
I
L
coil peak
coil p p
V
coil
P
+
3
R
P
I
----------------------- -
M
L
coil peak
2
2
R
-------------------------- -
1 e
coil
1.2
2.4
5
6
0.6
50
640
R
t –
+
+
coil
FB
VALUE
V
R
P
M
+
x
R
0.015 [A]
M
A
A
mH
Hz
+
s
0.3 [W]
UNIT
11
Table 2
Heatsink calculation
The value of the heatsink can be calculated in a standard
way with a method based on average temperatures. The
required thermal resistance of the heatsink is determined
by the maximum die temperature of 150 C. In general we
recommend to design for an average die temperature
not exceeding 130 C.
E
Measured or given values: P
T
The required heatsink thermal resistance is given by:
When we use the values given we find:
The heatsink temperature will be:
T
R
R
V
R
t
x
V
P
P
P
j
h
vert
XAMPLE
th h a
th h a
P
FB
sup
L
tot
M
= 120 C; R
= T
+ R
SYMBOL
amb
coil
=
=
+ (R
Calculated values
(hot)
T
----------------------- -
120 40
--------------------- -
j
th(j-c)
th(h-a)
P
6
T
tot
amb
= 4 K/W; R
14
7.8
0.02
0.000641
30
8.91
3.74
5.17
P
tot
4
R
VALUE
) = 40 + (7
+
th j c
2
tot
th(c-h)
=
= 6 W; T
+
7 K/W
R
= 2 K/W.
th c h
Product specification
6) = 82 C
TDA8359J
V
s
V
W
W
W
amb(max)
UNIT
= 40 C;

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