Philips TDA8928J Manual De Usuario
2004 May 05
12
Philips Semiconductors
Preliminary specification
Power stage 2 x 10 or 1 x 20 W class-D
audio amplifier
audio amplifier
TDA8928J
15.1
SE application
15.2
Package ground connection
The heatsink of the TDA8928J is connected internally to V
SS
.
15.3
Output power
The output power in SE self oscillating class-D applications can be estimated using the formula
The maximum current
should not exceed 2 A.
Where:
R
L
= load impedance
R
s
= series resistance of filter coil
P
o(1%)
= output power just at clipping.
The output power at THD = 10 %: P
o(10%)
= 1.25
×
P
o(1%)
.
15.4
Reference design
The reference design for a self oscillating class-D system for the TDA8928J is shown in Fig.5. The Printed-Circuit Board
(PCB) layout is shown in Figs 6, 7 and 8. The bill of materials is given in Section 15.4.2.
(PCB) layout is shown in Figs 6, 7 and 8. The bill of materials is given in Section 15.4.2.
P
o(1%)
R
L
R
L
R
ds(on)
R
s
+
+
(
)
------------------------------------------------
V
P
×
2
2
R
L
×
----------------------------------------------------------------------
=
I
O(max)
V
P
[
]
R
L
R
ds(on)
R
s
+
+
-------------------------------------------
=