wm8961 Wolfson Microelectronics plc, wm8961 Datasheet - Page 79

• Manufacturer Part Number: wm8961
• Description: Ultra-low Power Stereo Codec With 1w Stereo Class D Speaker Drivers And Ground Referenced Headphone Drivers
• Manufacturer: Wolfson Microelectronics plc

THERMAL SHUTDOWN AND STATUS
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WM8961
Table 62 VMIDSEL Control Registers
Table 63 Thermal Shutdown
Table 64 Thermal Status
R25 (19h)
Power Management (1)
R28 (1Ch) Anti-pop
R23 (17h)
Additional Control (1)
R48 (30h)
Additional Control (4)
R47 (2Fh) Pwr Mgmt (3)
REGISTER ADDRESS
REGISTER ADDRESS
REGISTER ADDRESS
The BUFDCCOPEN and BUFIOEN are used internally to enable the internal VMID and to enable the
internal fast start-up bias current. Users should enable both (set them to 1). The SOFT_ST bit can be
used to give a slow VMID ramp up voltage to reduce possibility of pops and clicks at start-up.
The speaker outputs can drive very large currents. To protect the WM8961 from overheating a
thermal shutdown circuit is included. If the device temperature reaches approximately 150
thermal shutdown circuit is enabled (TSDEN = 1; TSENSEN = 1) the speaker amplifiers (SPK_LP,
SPK_LN, SPK_RP and SPK_RN) will be disabled.
TSENSEN must be set to 1 to enable the temperature sensor when using the TSDEN thermal
shutdown function.
In addition to the thermal shutdown registers, there are 2 status (read only) registers which can be
used to check the status of the temperature sensor. These are the TEMP_WARN and TEMP_SHUT
status bits
8:7
6
4
3
2
8
1
1
0
BIT
BIT
BIT
VMIDSEL
VREF
BUFDCOPEN
SOFT_ST
TSDEN
TSENSEN
TEMP_WARN
BUFIOEN
TEMP_SHUT
LABEL
LABEL
LABEL
00
0
0
0
0
1
1
0
0
DEFAULT
DEFAULT
DEFAULT
VMID Divider Enable and Select
00 = VMID disabled (for OFF mode)
01 = 2 x 50kΩ divider enabled (for normal
playback / record)
10 = 2 x 250kΩ divider enabled (for low-power
standby)
11 = 2 x 5kΩ divider enabled (for fast start-up)
Enable master bias current source
0 = Master bias current source disabled
1 = Master bias current source enabled
Enables fast startup bias generation
Internal VMID and fast bias enable
For anti-pops and clicks. VMID Slow start up.
Ramp up voltage
0 = function disabled
1 = slow VMID slew rate selected
Thermal Shutdown Enable
0 = Thermal shutdown disabled
1 = Thermal shutdown enabled
(TSENSEN must be enabled for this function to
work)
Temperature Sensor Enable
0 = Temperature sensor disabled
1 = Temperature sensor enabled
Read only status of temperature sensor
triggers at 145 degrees C
Read only status of temperature sensor – triggers
at 125 degrees C
DESCRIPTION
DESCRIPTION
DESCRIPTION
PP, August 2009, Rev 3.1
Pre-Production
0
C and the
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