TDA8594 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
Manufacturer
TDA8594 Datasheet PDF : 48 Pages
| |||
NXP Semiconductors
TDA8594
I2C-bus controlled 4 Ć 50 W power ampliļ¬er
VP
DIAG
on
STB mute
standby
SVR
amplifier
output
tamp_on
soft
mute
toff
fast
mute
td(mute_off)
td(soft_mute) td(mute_on)
Fig 6. Start-up and shut-down timing in legacy mode
td(fast_mute)
001aad 171
7.9 Power-on reset and supply voltage spikes
If in I2C-bus mode the supply voltage drops below 5 V (see Figure 9), the content of the
I2C-bus latches cannot be guaranteed and the power-on reset will be activated. All latches
are reset, the ampliļ¬er is switched off and the DIAG pin is pulled LOW to indicate that a
power-on reset has occurred (bit DB2[D7]). When IB1[D0] is set, the power-on ļ¬ag is
reset, the DIAG pin will be released and the ampliļ¬er will start up.
In legacy mode a supply voltage drop below 5 V will switch off the ampliļ¬er and the DIAG
pin will not be pulled LOW.
7.10 Engine start and low voltage operation
The DC output voltage of the ampliļ¬er (VO) is set to half of the supply voltage and is
related to the voltage on the SVR pin (see Figure 7; VO = VSVR ā 1.4 V). A capacitor is
connected on the SVR pin to suppress the ripple on the power supply.
If the supply voltage drops, for instance, during an engine start, the output follows slowly
due to the SVR capacitor. The headroom voltage is the voltage needed for good operation
of the ampliļ¬er and is deļ¬ned as Vhr = VP ā VO (see Figure 7). If the headroom voltage
becomes lower than the headroom protection threshold of 1.6 V, the headroom protection
is activated to prevent pop noise at the output. This protection ļ¬rst activates the fast mute
and then discharges the capacitors on the SVR and ACGND pins to generate more
headroom for the ampliļ¬er (see Figure 8).
TDA8594_2
Product data sheet
Rev. 02 ā 11 December 2007
Ā© NXP B.V. 2007. All rights reserved.
11 of 48
Share Link: 