參數(shù)資料
型號(hào): SI3225DC0-EVB
廠商: Silicon Laboratories Inc
文件頁數(shù): 53/112頁
文件大?。?/td> 0K
描述: DAUGHTER CARD W/SI3200 INTERFACE
標(biāo)準(zhǔn)包裝: 1
系列: ProSLIC®
主要目的: 接口,模擬前端(AFE)
已用 IC / 零件: Si3225
已供物品: 板,CD
Si3220/25 Si3200/02
Rev. 1.3
45
Not
Recommended
fo
r N
ew
D
esi
gn
s
3.10. Loop Closure Detection
Loop closure detection is required to accurately signal a
terminal device going off-hook during the Active, On-
Hook Transmission (forward or reverse polarity), and
ringing linefeed states. The functional blocks required to
implement a loop closure detector are shown in
Figure 21, and the register set for detecting a loop
closure event is provided in Table 25. The primary input
to the system is the loop current sense value from the
voltage/current/power
monitoring
circuitry
and
is
reported in the ILOOP RAM address.
The loop current (ILOOP) is computed by the input signal
processor (ISP) using the equations shown below.
Refer to Figure 18 on page 38 for the discrete bipolar
transistor references) used in the equation below (Q1,
Q2, Q5 and Q6 – note that the Si3200/2 has
corresponding MOS transistors). The same ILOOP
equation applies to the discrete bipolar linefeed as well
as the Si3200/2 linefeed device. The following equation
is conditioned by the CMH status bit in register LCRRTP
and by the linefeed state as indicated by the LFS field in
the LINEFEED register.
If the CMHITH (RAM 36) threshold is exceeded, the
CMH bit is 1, and IQ1 is forced to zero in the
FORWARD-ACTIVE and TIP-OPEN states, or IQ2 is
forced to zero in the REVERSE-ACTIVE and RING-
OPEN states. The other currents in the equation are
allowed to contribute normally to the ILOOP value.
The conditioning due to the CMH bit (LCRRTP Register)
and LFS field (LINEFEED Register) states can be
summarized as follows:
IQ1 = 0 if (CMH = 1 AND (LFS = 1 OR LFS = 3))
IQ2 = 0 if (CMH = 1 AND (LFS = 5 OR LFS = 7))
The output of the ISP is the input to a programmable
digital low-pass filter that removes unwanted ac signal
components before threshold detection.
The low-pass filter coefficient is calculated using the
following equation and is entered into the LCRLPF RAM
location:
LCRLPF = [(2
f x 4096)/800] x 23
Where f = the desired cutoff frequency of the filter.
The programmable range of the filter is from 0h (blocks
all signals) to 4000h (unfiltered). A typical value of 10
(0A10h) is sufficient to filter out any unwanted ac
artifacts while allowing the dc information to pass
through the filter.
The output of the low-pass filter is compared to a
programmable threshold, LCROFFHK. Hysteresis is
enabled
by
programming
a
second
threshold,
LCRONHK, to detect the loop going to an open or on-
hook state. The threshold comparator output feeds a
programmable debounce filter. The output of the
debounce filter remains in its present state unless the
input remains in the opposite state for the entire period
of time programmed by the loop closure debounce
interval, LCRDBI. There is also a loop closure mask
interval, LCRMASK, that is used to mask transients
caused when an internal ringing burst (with no offset)
ends in the presence of a high REN load. If the
debounce interval has been satisfied, the LCR bit is set
to indicate that a valid loop closure has occurred.
Figure 21. Loop Closure Detection Circuitry
I
loop
I
Q1
I
Q6
I
Q5
I
Q2 in TIP-OPEN or RING-OPEN
I
Q1
I
Q6
I
Q5
I
Q2
+
2
---------------------------------------------------- in all other states
=
+
=
I
Q1
LFS
LCRLPF
LCROFFHK
Input
Signal
Processor
Digital
LPF
Loop Closure
Threshold
Debounce
Filter
+
LCR
LCRONHK
LOOPS
LOOPE
Interrupt
Logic
LCRDBI
Loop
Closure
Mask
LCRMASK
I
Q2
I
Q5
I
Q6
CMH
I
LOOP
相關(guān)PDF資料
PDF描述
SEK220M400ST CAP ALUM 22UF 400V 20% RADIAL
CP2201EK KIT EVAL FOR CP2201 ETH CTRLR
PM1210-820J-RC INDUCTOR 82UH 5% 1210 SMD
H3WWH-6036G IDC CABLE - HPL60H/AE60G/HPL60H
UPS2C471MRD CAP ALUM 470UF 160V 20% RADIAL
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SI3225DCX-EVB 功能描述:子卡和OEM板 Si3225 Daughter Card RoHS:否 制造商:BeagleBoard by CircuitCo 產(chǎn)品:BeagleBone LCD4 Boards 用于:BeagleBone - BB-Bone - Open Source Development Kit
Si3225-FQ 功能描述:電信線路管理 IC Dual-Channel SLIC/ codec RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
SI3225-FQR 制造商:Silicon Laboratories Inc 功能描述:
Si3225-G-FQ 功能描述:電信線路管理 IC Dual-Channel SLIC codec RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray
SI3225-G-FQR 功能描述:電信線路管理 IC Dual-CH SLIC/codec Ext Ringing Support RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray