WM8994 Datasheet, PDF (235/359 Pages) Wolfson Microelectronics plc – Multi-Channel Audio Hub CODEC for Smartphones

Production Data
WM8994
THERMAL SHUTDOWN
The WM8994 incorporates a temperature sensor which detects when the device temperature is within
normal limits or if the device is approaching a hazardous temperature condition. The temperature
sensor can be configured to automatically disable the audio outputs of the WM8994 in response to an
overtemperature condition (approximately 150ºC).
The temperature status can be output directly on a GPIO pin, as described in the “General Purpose
Input/Output” section. The temperature sensor can also be used to generate Interrupt events, as
described in the “Interrupts” section. The GPIO and Interrupt functions can be used to indicate either
a Warning Temperature event or the Shutdown Temperature event.
The temperature sensor is enabled by setting the TSHUT_ENA register bit. When the TSHUT_OPDIS
is also set, then a device over-temperature condition will cause the speaker outputs (SPKOUTL and
SPKOUTR) of the WM8994 to be disabled; this response is likely to prevent any damage to the
device attributable to the large currents of the output drivers.
Note that, to prevent pops and clicks, TSHUT_ENA and TSHUT_OPDIS should only be updated
whilst the speaker and headphone outputs are disabled.
REGISTER
ADDRESS
R2 (0002h)
Power
Management
(2)
BIT
LABEL
14 TSHUT_ENA
13 TSHUT_OPDIS
Table 139 Thermal Shutdown
DEFAULT
DESCRIPTION
1
Thermal sensor enable
0 = Disabled
1 = Enabled
1
Thermal shutdown control
(Causes audio outputs to be disabled
if an overtemperature occurs. The
thermal sensor must also be enabled.)
0 = Disabled
1 = Enabled
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PD, April 2012, Rev 4.4
235