U4091BM Datasheet, PDF (4/29 Pages) TEMIC Semiconductors – Programmable Telephone Audio Processor

U4091BM
RECIN 1
44 STRC
TXACL 2
43 STC
MIC3 3
42 STO
MIC2 4
41 ^AMREC
MIC1 5
40 AMPB
RECO2 6
39 MICO
RECO1 7
38 _IMPSW
IND 8
VL ₉
SENSE ₁₀
37 _TLDT
36 _INLDT
35 _INLDR
GND 11
34 TLDR
VB 12
33 _CT
SAO2 13
32 _BNMT
SAO1 14
31 _BNMR
VMPS ₁₅
30 _ADIN
VMP ₁₆
29 _ES
VMIC ₁₇
28 _RESET
TSACL ₁₈
27 _OSCOUT
VRING ₁₉
IMPA ₂₀
26 _OSCIN
25 _SDA
COSC ₂₁
24 _SCL
SWOUT ₂₂
23 _INT
14751
Figure 2. Pinning
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 R_SENSE C_IND (R_DC R₃₀) / (R_DC + R₃₀)
The U4091BM 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.
Supply Structure of the Chip
A main benefit of the U4091BM 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 3.
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 the serial bus, all the
blocks which are needed have to be switched on via
the serial bus.
4 (29)
Rev. A1, 02-Jun-98
Target Specification