TDA8920B NXP Semiconductors, TDA8920B Datasheet - Page 10

• Manufacturer Part Number: TDA8920B
• Description: The TDA8920B is a high efficiency class-D audio power amplifier with very lowdissipation
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TDA8920B_2
Product data sheet
8.3.4 Supply voltage protections
If the supply voltage drops below 12.5 V, the UnderVoltage Protection (UVP) circuit is
activated and the system will shut-down correctly. If the internal clock is used, this
switch-off will be silent and without pop noise. When the supply voltage rises above the
threshold level, the system is restarted again after 100 ms. If the supply voltage exceeds
shut-down. It is re-enabled as soon as the supply voltage drops below the threshold level.
So in this case no timer of 100 ms is started.
An additional UnBalance Protection (UBP) circuit compares the positive analog (V
and the negative analog (V
between them exceeds a certain level. This level depends on the sum of both supply
voltages. An expression for the unbalanced threshold level is as follows:
V
When the supply voltage difference drops below the threshold level, the system is
restarted again after 100 ms.
Example: With a symmetrical supply of 30 V, the protection circuit will be triggered if the
unbalance exceeds approximately 9 V; see also
In
Table 4:
[1]
[2]
[3]
Protection name
OTP
OCP
WP
UVP
OVP
UBP
33 V the OverVoltage Protection (OVP) circuit is activated and the power stages will
th(ub)
Table 4
Hysteresis of 20 C will influence restart timing depending on heatsink size.
Only complete shut-down of amplifier if short-circuit impedance is below threshold of 1 . In all other cases
current limiting: resulting in clipping output signal.
Fault condition detected during (every) transition between standby-to-mute and during restart after
activation of OCP (short to one of the supply lines).
0.15
an overview is given of all protections and the effect on the output signal.
Overview of TDA8920B protections
(V
DDA
Rev. 02 — 07 November 2005
+ V
Complete shut-down
Y
N
Y
Y
Y
Y
[3]
[2]
SSA
SSA
).
) supply voltages and is triggered if the voltage difference
Restart directly
Y
Y
Y
N
Y
N
[1]
[2]
Section
2
13.7.
100 W class-D power amplifier
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
TDA8920B
Restart every 100 ms
N
N
N
Y
N
Y
[1]
[2]
DDA
10 of 34
)