wm8350 Wolfson Microelectronics plc, wm8350 Datasheet - Page 147

• Manufacturer Part Number: wm8350
• Description: Wolfson Audioplus? Stereo Codec With Power Management
• Manufacturer: Wolfson Microelectronics plc

Production Data
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15.2.2
The Current Limit Switch can be connected to voltages which may be higher than the device LINE
voltage. To support this capability, the switch is powered from the highest available voltage; this
requires a bulk detection circuit in order to select the highest available voltage. The bulk detection
circuit is always enabled whenever the Current Limit Switch is enabled.
It is possible to control whether the bulk detection circuit is enabled or not when the Current Limit
Switch is disabled. This is controlled in Active mode by the LS_PROT bit, and in Hibernate mode by
the LS_HIB_PROT bit.
Disabling the Bulk Detection circuit will reduce power consumption. It is important to note, however,
that the Bulk Detection circuit should always be enabled if voltages greater than LINE could be
present on IP or OP. This applies regardless of whether the Current Switch is open or closed.
R199 (C7h)
Limit switch
control
Table 91 Current Limit Switch Bulk Detection Control
15.2.3
The response to an over-current condition is selectable. To prevent false alarms during short current
surges, faults are only signalled if the fault condition persists.
R199 (C7h)
Limit switch
control
Table 92 Fault Response for the Current Limit Switch
The limit switch has its own first-level interrupt, OC_INT (see Section 24). This contains a single
second-level interrupt, OC_LS_EINT, indicating an over-current condition. OC_LS_EINT can be
masked by setting the IM_OC_LS_EINT bit.
R29 (1Dh)
Over Current
Interrupt Status
R37 (25h)
Over Current
Interrupt Mask
Table 93 Current Limit Switch Interrupts
ADDRESS
ADDRESS
ADDRESS
CURRENT LIMIT SWITCH BULK DETECTION CONTROL
INTERRUPTS AND FAULT PROTECTION
15:14
BIT
BIT
15
15
BIT
1
0
OC_LS_EINT
IM_OC_LS_EINT
LS_ERRACT
[1:0]
LS_HIB_PRO
T
LS_PROT
LABEL
LABEL
LABEL
DEFAULT
DEFAULT
00
1
1
Limit Switch Over-current interrupt.
(Rising Edge triggered)
Note: This bit is cleared once read.
Mask bit for Limit switch over-current
interrupt
When set to 1, IM_OC_LS_EINT masks
OC_LS_EINT in R29 and does not trigger
an OC_INT interrupt when OC_LS_EINT is
set).
Controls the bulk detection circuit when
Limit Switch is disabled in Hibernate
mode.
0 = bulk detection disabled
1 = bulk detection enabled
Controls the bulk detection circuit when
Limit Switch is disabled in Active mode.
0 = bulk detection disabled
1 = bulk detection enabled
Current limit detection behaviour
00 = ignore
01 = disable switch
10 = shut down system
11 = shut down system
DESCRIPTION
DESCRIPTION
DESCRIPTION
PD, June 2009, Rev 4.1
WM8350
147