tda8589 NXP Semiconductors, tda8589 Datasheet - Page 11

• Manufacturer Part Number: tda8589
• Description: Tda8589j; Tda8589xj I2c-bus Controlled 4 X 45 Watt Power Amplifier And Multiple Voltage Regulator
• Manufacturer: NXP Semiconductors

Philips Semiconductors
VOLTAGE REGULATORS
The voltage regulator section contains:
The quiescent current condition has a very low current
level of 150 A typical with only regulator 2 active. The
TDA8589 uses low dropout voltage regulators for use in
low voltage applications.
All of the voltage regulators except for the standby
regulator can be controlled via the I
regulator section of this device has two power switches
which are capable of delivering unregulated 400 mA
continuous current, and has several fail-safe protection
modes. It conforms to peak transient tests and protects
against continuous high voltage (24 V), short-circuits and
thermal stress. A reset warning signal is asserted if
regulator 2 is out of regulation. Regulator 2 will try to
maintain output for as long as possible even if a thermal
shut-down or any other fault condition occurs. During
overvoltage stress conditions, all outputs except
regulator 2 will switch off and the device will be able to
supply a minimum current for an indefinite amount of time
sufficient for powering the memory of a microcontroller.
Provision is made for an external reserve supply capacitor
to be connected to pin BUCAP which can store enough
energy to allow regulator 2 to supply a microcontroller for
a period long enough for it to prepare for a loss-of-voltage.
Regulator 2
Regulator 2 is intended to supply the microcontroller and
has a low quiescent current. This supply cannot be shut
down in response to overvoltage stress conditions, and is
not I
being damaged by overvoltage which could occur during a
disturbance of the I
during load dump transients or during a high
thermal-protection condition.
Backup capacitor
The backup capacitor is used as a backup supply for the
regulator 2 output when the battery supply voltage (V
cannot support the regulator 2 voltage.
2004 Feb 24
Four switchable regulators and one permanent active
regulator
Two power switches with loss-of-ground protection
Reset push-pull output
Backup functionality.
I
amplifier and multiple voltage regulator
2
2
C-bus controlled 4
C-bus controllable to prevent the microcontroller from
2
C-bus. This supply will not shut down
2
45 Watt power
C-bus. The voltage
P
)
11
Backup function
The backup function is implemented by a switch function,
which behaves like an ideal diode between pins V
and BUCAP; the forward voltage of this ideal diode
depends on the current flowing through it. The backup
function supplies regulator 2 during brief periods when no
supply voltage is present on pin V
capacitor to be connected to pin BUCAP and ground.
When the supply voltage is present on pin V
capacitor will be charged to a level of V
supply voltage is absent from pin V
be used to supply regulator 2 for a brief period (t
calculated using the formula:
Example: V
C
When an overvoltage condition occurs, the voltage on
pin BUCAP is limited to approximately 24 V; see Fig.5.
t
backup
backup
= 100 F provides a t
=
C
P
backup
= 14.4 V, V
TDA8589J; TDA8589xJ
R
L
O(REG2)
V
-------------------------------------------------------- -
P
backup
–
= 5 V, R
V
V
P
. It requires an external
O REG2
P
O REG2
of 177 ms.
, this charge can then
Product specification
P
L
0.3 V. When the
= 1 k and
–
P
0.5
this
backup
P
)