- 您现在的位置：买卖IC网 > PDF目录225366 > U3900BM-AFN Programmable Telephone Audio Processor PDF资料下载
参数资料
| 型号： | U3900BM-AFN |
| 英文描述： | Programmable Telephone Audio Processor |
| 中文描述： | 程控电话音频处理器 |
| 文件页数： | 4/34页 |
| 文件大小： | 762K |
| 代理商： | U3900BM-AFN |
第1页第2页第3页当前第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页
U3900BM
Rev. A2, 25-Aug-98
Target Specification
12 (34)
3
DC Line Interface and
Supply-Voltage Generation
The DC line interface consists of an electronic inductance
and a dual-port output stage which charges the capacitors
at VMPS and VB. The value of the equivalent inductance
is given by:
L = 2
RSENSE
CIND
(RDC
R30) / (RDC + R30)
The U3900BM contains two identical series regulators
which provide a supply voltage VMP of 3.3 V suitable for
a microprocessor. In speech mode, both regulators are
active
because
VMPS
and
VB
are
charged
simultaneously by the DC-line interface. The output
current is 6 mA. The capacitor at VMPS is used to provide
the microcomputer with sufficient power during long line
interruptions. Thus, long flash pulses can be bridged or an
LCD display can be turned on for more than 2 seconds
after going on-hook. When the system is in ringing mode,
VB is charged by the on–chip ringing power converter. In
this mode, only one regulator is used to supply VMP with
maximum 3 mA.
3.1
Supply Structure of the Chip
As main benefit of the U3900BM is the easy implementa-
tion of various applications due to the flexible system
structure of the chip.
Possible applications:
D Group listening phone
D Hands-free phone
D Phones which feature ringing with the built-in speaker
amplifier
D Answering machine with external supply
The special supply topology for the various functional
blocks is illustrated in figure 11.
There are four major supply states:
1.
Speech condition
2.
Power down (pulse dialing)
3.
Ringing
4.
External supply
1. In speech condition, the system is supplied by the line
current. If the LIDET-block detects a line voltage
above approximately 2 V, the internal signal VLON is
activated. This is detected via serial bus, all necessary
the blocks have to be switched on via the serial bus.
For line voltages below 2 V, the switches remain in
quiescent state as shown in the diagram.
2. When the chip is in power-down mode (Bit
LOMAKE), e.g., during pulse dialing, all internal
blocks are disabled via the serial bus, except the
oscillator. In this condition, the voltage regulators and
their internal bandgap are the only active blocks.
3. During ringing, the supply for the system is fed into
VB via the Ringing Power Converter (RPC).
Normally, the speaker amplifier in single-ended mode
is used for ringing. The frequency for the melody is
generated by the DTMF/Melody generator.
4. In an answering machine, the chip is powered by an
external supply via Pin VB. The answering machine
connections could be directly put to U3900BM. The
answering machine is connected to the Pin AMREC.
For the output AMREC, an AGC function is select-
able via the serial bus. The output of the answering
machine will be connected to the Pin AMPB, which is
directly connected to the switching matrix, and thus
enables the signal to be switched to every desired
output.
14573
+
–
+
3.3 V
5.5 V
VMPS
VMP
5.5 V
V
470
F
300 k
–
+
R
47
F
220
F
1
F
10
RSENSE
R
IND
C
VL
VB
Figure 12. Supply generator
4
Ringing Power Converter
(RPC)
The RPC transforms the input power at VRING (high
voltage/ low current) into an equivalent output power at
VB (low voltage/ high current) which is capable of
driving the low-ohmic loudspeaker. The input impedance
at VRING is adjustable from 3 k
W to 12 kW by RIMPA
(ZRING = RIMPA / 100) and the efficiency of the step-
down converter is approximately 65%.
相关PDF资料 |
PDF描述 |
|---|---|
| U3900BM-AFNG3 | Programmable Telephone Audio Processor |
| U4479B | DVB-Cable IF Converter and Full Multi-Standard Video-/Sound IF Processing |
| U4479B-MFLG3 | DVB-Cable IF Converter and Full Multi-Standard Video-/Sound IF Processing |
| U4488B | Quasi-Split Sound Circuit and AM Demodulator |
| U54-W-8 | GENERAL PURPOSE INDUCTOR |
相关代理商/技术参数 |
参数描述 |
|---|---|
| U3900BM-AFNG3 | 制造商:TEMIC 制造商全称:TEMIC Semiconductors 功能描述:Programmable Telephone Audio Processor |
| U392N | 制造商:APEM 功能描述:Switch Hardware |
| U39J1ZGE9 | 制造商:C&K Components 功能描述:- Bulk |
| U39MYW1QE | 制造商:C&K Components 功能描述:U39MYW1QE - Bulk |
| U3B | 制造商:VISHAY 制造商全称:Vishay Siliconix 功能描述:Surface Mount Ultrafast Plastic Rectifier |
发布紧急采购，3分钟左右您将得到回复。