TDF8555J NXP Semiconductors, TDF8555J Datasheet - Page 17

• Manufacturer Part Number: TDF8555J
• Description: The TDF8555J is one of a new generation of complementary quad Bridge-Tied Load(BTL) audio power amplifiers with full I²C-bus controlled diagnostics, multiple voltageregulator and two power switches intended for automotive applications
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDF8555J
Product data sheet
There are two possible situations:
The first and second stages of the start-up diagnostics can be repeated:
Start-up with the start-up diagnostics (IB1[D1] = 1) and the amplifier start enabled
(IB1[D0] = 1). Wait until DB4[D6] = 0 which indicates that the start-up diagnostics cycle is
completed. Read the start-up diagnostics information. Shut down the amplifier by making
the start-up bit logic 0. When DB4[D6] = 0, the amplifier is completely shut down and a
new start-up cycle can be programmed.
Table 5.
[1]
If during the start-up diagnostics an engine start occurs, the generated offset to measure
the DC load is reduced and the start-up diagnostics cannot be performed correctly. In this
case the invalid combination DBx[D4:D5] = 11 is set.
The start-up diagnostics information in the I
detection allowing the start-up diagnostics information to be read when IB4[D0] = 1 (the
advanced load detection is enabled). If IB4[D0] = 0, only normal and not normal loads can
be detected.
Remark: The shorted load, and short to V
diagnostics is cleared after an I
situation: when the short is removed, the bits are cleared. The DBx[D5] and DBx[D4]
information, generated at start-up, is refreshed after a new start-up diagnostics cycle.
DC load bits
DBx[D5]
0
0
1
1
•
•
the start-up diagnostics are enabled (IB1[D1] = 1) and the amplifier start is not
enabled (IB1[D0] = 0), bit “start-up diag busy bit” is reset when the start-up
diagnostics are completed, and the I
diagnostics bit re-starts the start-up diagnostics. The invalid bits are set and bit
“start-up diag busy bit” indicates that the start-up diagnostics are not completed.
the start-up diagnostics are enabled (IB1[D1] = 1) and the amplifier start is enabled
(IB1[D0] = 1). After the first stage, the amplifier is started and when start-up is
completed, just before the start-up mute release (DC output voltage is 1.4 V below
midtap voltage), bit “start-up diag busy bit” indicates that the startup diagnostic is
completed. It is not necessary to toggle the start-up diagnostics and has no purpose.
DBx[D3] indicates a shorted load; DBx[D1] indicates a short to V
When set, D4, D5 have no meaning.
Start-up diagnostics I
[1]
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 15 September 2011
4 45 W power amplifier with multiple voltage regulator
DBx[D4]
0
1
0
1
2
2
C-bus read. Bits DBx[D5] and DBx[D4] indicate the real
C-bus bits
2
C-bus data bits are set. Toggling the start-up
P
2
or ground information from the start-up
C-bus bits is combined with the AC load
P
; DBx[D0] indicates a short to ground.
Meaning
normal load
line driver mode
open load
invalid: overvoltage or
undervoltage (V
occurred, or start-up
diagnostics not completed, or
channel has short to V
indicated in second stage
TDF8555J
© NXP B.V. 2011. All rights reserved.
P
< 10 V) has
P
;
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