TDF8555J NXP Semiconductors, TDF8555J Datasheet - Page 22

• 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
8. Functional description voltage regulator section
TDF8555J
Product data sheet
8.1 Switched regulator outputs
8.2 Standby regulator outputs
8.3 Bus controller regulator output
8.4 Backup capacitor
The voltage regulator section contains:
The quiescent current has a very low level of 180 A (typical value) with only regulators 2
and 6 active. Due to the low voltage operation of the application, low dropout voltage
regulators are used.
All the regulators, except for the standby regulators, can be controlled by the I
device has in addition to the regulators, two I
capable of delivering 400 mA continuous current. This device has several fail-safe
protection modes. This module conforms to peak transient tests and protects against high
continuous voltage (24 V), short-circuits and thermal stress. The standby regulators will
maintain output as long as possible even in thermal shutdown or any other fault condition.
During overvoltage stress, all outputs except the standby regulators will shut off and the
device is able to supply a minimum current for indefinite amount of time allowing
sustained memory for a microprocessor. Also, there is a provision for use of a reserve
supply capacitor that will hold enough energy for regulator 2 to allow a microprocessor to
prepare for loss of voltage.
Switched outputs (regulator 1, 3, 4 and 5) can be programmed by the I
an internal protection for overtemperature conditions. The regulated outputs supplying
pulsed current loads will contaminate the line with high frequency noise so it is important
to prevent any cross-coupling between the regulated outputs, particularly with the 8.3 V
supply for audio.
Regulators 2 and 6 are used for the microcontroller and bus controller supply. They have
a low quiescent current and cannot be switched. These regulators will not shut down with
the switched regulators and cannot be controlled by the I
shut down during load dump transients or high temperature protection.
Regulator 6 has virtually the same functionality as regulator 2 but has different output
voltage and current.
The backup capacitor (C
the battery supply voltage (V
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Four switchable regulators and two permanent active regulators
Second supply pin to reduce dissipation using an external DC-to-DC converter
Two power switches with loss-of-ground protection
Backup functionality
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 15 September 2011
backup
P
4 45 W power amplifier with multiple voltage regulator
) is used as a backup supply for the regulator 2 output when
) cannot support the regulator 2 voltage.
2
C-controlled power switches which are
2
C-bus. These regulators will not
TDF8555J
2
© NXP B.V. 2011. All rights reserved.
C-bus and have
2
C-bus. The
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