Datasheet

TAS5631
SLES221C –JULY 2009–REVISED APRIL 2010 www.ti.com
ERROR REPORTING
The SD, OTW, OTW1, and OTW2 pins are active-low, open-drain outputs. Their function is for protection-mode
signaling to a PWM controller or other system-control device.
Any fault resulting in device shutdown is signaled by the SD pin going low. Likewise, OTW and OTW2 go low
when the device junction temperature exceeds 125°C and OTW1 goes low when the junction temperature
exceeds 100°C (see the following table).
OTW2,
SD OTW1 DESCRIPTION
OTW
0 0 0 Overtemperature (OTE) or overload (OLP) or undervoltage (UVP)
Overload (OLP) or undervoltage (UVP). Junction temperature higher than 100°C (overtemperature
0 0 1
warning)
0 1 1 Overload (OLP) or undervoltage (UVP)
1 0 0 Junction temperature higher than 125°C (overtemperature warning)
1 0 1 Junction temperature higher than 100°C (overtemperature warning)
1 1 1 Junction temperature lower than 100°C and no OLP or UVP faults (normal operation)
Note that asserting RESET low forces the SD signal high, independent of faults being present. TI recommends
monitoring the OTW signal using the system microcontroller and responding to an overtemperature warning
signal by, e.g., turning down the volume to prevent further heating of the device resulting in device shutdown
(OTE).
To reduce external component count, an internal pullup resistor to 3.3 V is provided on both SD and OTW
outputs. Level compliance for 5-V logic can be obtained by adding external pullup resistors to 5 V (see the
Electrical Characteristics table of this data sheet for further specifications).
DEVICE PROTECTION SYSTEM
The TAS5631 contains advanced protection circuitry carefully designed to facilitate system integration and ease
of use, as well as to safeguard the device from permanent failure due to a wide range of fault conditions such as
short circuits, overload, overtemperature, and undervoltage. The TAS5631 responds to a fault by immediately
setting the power stage in a high-impedance (Hi-Z) state and asserting the
SD
pin low. In situations other than
overload and overtemperature error (OTE), the device automatically recovers when the fault condition has been
removed, i.e., the supply voltage has increased.
The device functions on errors, as shown in the following table.
BTL Mode PBTL Mode SE Mode
Local Error In Turns Off Local Error In Turns Off Local Error In Turns Off
A A A
A + B A + B
B B B
A + B + C + D
C C C
C + D C + D
D D D
Bootstrap UVP does not shut down according to the table; it shuts down the respective half-bridge.
PIN-TO-PIN SHORT-CIRCUIT PROTECTION (PPSC)
The PPSC detection system protects the device from permanent damage if a power output pin (OUT_X) is
shorted to GND_X or PVDD_X. For comparison, the OC protection system detects an overcurrent after the
demodulation filter, whereas PPSC detects shorts directly at the pin before the filter. PPSC detection is
performed at startup, i.e., when VDD is supplied; consequently, a short to either GND_X or PVDD_X after
system startup does not activate the PPSC detection system. When PPSC detection is activated by a short on
the output, all half-bridges are kept in a Hi-Z state until the short is removed; the device then continues the
start-up sequence and starts switching. The detection is controlled globally by a two-step sequence. The first
step ensures that there are no shorts from OUT_X to GND_X; the second step tests that there are no shorts
from OUT_X to PVDD_X. The total duration of this process is roughly proportional to the capacitance of the
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