tda8357j-n2 NXP Semiconductors, tda8357j-n2 Datasheet - Page 11

• Manufacturer Part Number: tda8357j-n2
• Description: Full Bridge Vertical Deflection Output Circuit In Lvdmos
• Manufacturer: NXP Semiconductors

Philips Semiconductors
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
Table 2 Calculated values
2002 May 06
P
P
I
I
L
R
R
f
t
V
R
t
x
V
P
P
P
tot
coil(peak)
coil(p-p)
vert
FB
vert
sup
L
coil
P
FB
sup
L
tot
Full bridge vertical deflection output circuit
in LVDMOS
coil
M
M
= P
=
+ R
SYMBOL
SYMBOL
=
------------------------------- -
I
sup
coil peak
coil
V
P
(hot)
3
P
I
----------------------- -
L
coil peak
2
2
R
+
coil
0.000802
VALUE
VALUE
0.725
V
1.45
8.82
0.02
4.45
1.93
2.52
640
+
7.9
1.5
50
11
11
29
P
R
M
0.015 [A])
+
0.3 [W]
UNIT
UNIT
mH
Hz
W
W
W
A
A
V
V
s
s
11
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 specific values are included, this becomes
The heatsink temperature will be
T
R
R
j
h
XAMPLE
th h a
th h a
= 110 C; R
= T
–
–
amb
=
=
+ (R
T
----------------------- -
110 40
--------------------- -
j
th(j-c)
th(h-a)
–
P
3.0
T
tot
–
amb
= 6 K/W; R
–
–
P
tot
6
R
) = 40 + (3
+
th j c
2
tot
–
th(c-h)
=
= 3 W; T
+
15 K/W
R
= 2 K/W.
th c h
Product specification
15) = 85 C
TDA8357J
amb
–
= 40 C;