si3210 ETC-unknow, si3210 Datasheet - Page 36

• Manufacturer Part Number: si3210
• Description: Proslic Programmable Cmos Slic/codec With Ringing/battery Voltage Generation
• Manufacturer: ETC-unknow

Si 3210/ Si3 211/S i32 12
leakages, etc. The total I
smaller than 80 mA.
where
transistors Q5 and Q6.
The minimum value for VBATH is therefore given by the
following:
The ProSLIC is designed to create a fully balanced
ringing waveform, meaning that the TIP and RING
common mode voltage, (V
voltage
automatically set to the following:
VCMR is an indirect register which provides the
headroom by the ringing waveform with respect to the
VBATH rail. The value is set as a 4-bit setting in indirect
Register 40 with an LSB voltage of 1.5 V/LSB.
The output of the low pass filter is compared to a
programmable threshold, RPTP (indirect Register 29).
The threshold comparator output feeds a programmable
debouncing filter. The output of the debouncing filter
remains in its present state unless the input remains in
the opposite state for the entire period of time
programmed by the ring trip debounce interval,
RTDI[6:0] (direct Register 70). If the debounce interval
has been satisfied, the RTP bit of direct Register 68 will
be set to indicate that a valid ring trip has occurred. A
ring trip interrupt is generated if enabled by the RTIE bit
(direct Register 22). Table 29 lists the registers that
must be written or monitored to correctly detect a ring
36
LCS
V
is
OVR
VBATH
is the minimum expected current gain of
VCM _ RING
Processor
referred
Signal
=
Input
LFS
I
LOAD,PK
=
V
AC,PK
=
ISP_OUT
to
VBATH VCMR
--------------------------------------------- -
------------ - 80.6
TIP
+
LOAD,PK
+
as
V
1
+ V
ROFF
2
VCM_RING
–
RING
Digital
N RTP
+
LPF
current should be
V
)/2, is fixed. This
OVR
+
Figure 21. Ring Trip Detector
1 V
Threshold
Ring Trip
Preliminary Rev. 1.11
R PTP
and
+
–
is
Register 40 should be set with the calculated V
provide voltage headroom during ringing.
Silicon revisions C and higher support the option to
briefly increase the maximum differential current limit
between the voltage transition of TIP and RING from
ringing to a dc linefeed state. This mode is enabled by
setting ILIMEN = 1 (direct Register 108, bit 7).
Ring Trip Detection
A ring trip event signals that the terminal equipment has
gone off-hook during the ringing state. The ProSLIC
performs ring trip detection digitally using its on-chip
monitor A/D converter. The functional blocks required to
implement ring trip detection is shown in Figure 21. The
primary input to the system is the Loop Current Sense
value provided by the current monitoring circuitry and
reported in direct Register 79. LCS data is processed by
the input signal processor when the ProSLIC is in the
ringing state as indicated by the Linefeed Shadow
register (direct Register 64). The data then feeds into a
programmable digital low pass filter, which removes
unwanted ac signal components before threshold
detection.
trip condition.
The recommended values for RPTP, NRTP, and RTDI
vary according to the programmed ringing frequency.
Register values for various ringing frequencies are
given in Table 30.
DBIRAW
Debounce
Filter
RTDI
R TP
Interrupt
Logic
RTIE
R TIP
OVR
to