U4091BM TEMIC Semiconductors, U4091BM Datasheet - Page 4

• Manufacturer Part Number: U4091BM
• Description: Programmable Telephone Audio Processor
• Manufacturer: TEMIC Semiconductors

U4091BM
4 (29)
SWOUT
TXACL
RECO2
RECO1
TSACL
VRING
SENSE
RECIN
VMPS
VMIC
COSC
SAO2
SAO1
MIC3
MIC2
MIC1
IMPA
GND
VMP
IND
VB
VL
10
11
12
13
14
15
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
Figure 2. Pinning
14751
34
33
32
44
43
42
41
40
39
38
37
36
35
28
24
23
31
30
29
27
26
25
Target Specification
STRC
STC
STO
AMREC
AMPB
MICO
IMPSW
TLDT
INLDT
INLDR
CT
BNMT
BNMR
ADIN
ES
RESET
OSCOUT
OSCIN
SDA
SCL
INT
TLDR
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
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
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
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.
2.
3.
4.
1. In speech condition, the system is supplied by the line
amplifier
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.
Speech condition
Power down (pulse dialing)
Ringing
External supply
because
R
SENSE
VMPS
C
IND
(R
and
DC
VB
Rev. A1, 02-Jun-98
R
30
) / (R
are
DC
charged
+ R
30
)