TELEFUNKEN Semiconductors
U4091B
Programmable Telephone Audio Processor
Description
The programmable telephone audio processor U4091B is
a linear integrated circuit for use in feature phones, an-
swering machines and fax machines. It contains the
speech circuit, tone ringer interface with dc/dc converter,
sidetone equivalent and ear protection rectifiers. The cir-
cuit is line powered and contains all components
necessary for amplification of signals and adaptation to
the line.
An integrated voice switch with loudspeaker amplifier al-
lows handsfree or loudhearing operation. With an
anti-feedback function, acoustical feedback during loud-
hearing can be reduced significantly. The generated
supply voltage is suitable for a wide range of peripheral
circuits.
Features
D
D
D
D
Speech circuit with anti-clipping
Tone ringer interface with dc / dc converter
Speaker amplifier with anti-distortion
Power supply management, regulated, unregulated
and a special supply for electret microphone
Benefits
D
Savings of one piezo electric transducer
D
Complete system integration of analog signal proces-
sing on one chip
D
Very few external components
D
Voice switch
Applications
Feature phone, answering machine, fax machine, speaker
phone
Voice
switch
Rev. A1: 12.07.1995
Preliminary Information
ÁÁ
ÁÁ
BUS
Speech
circuit
Audio
amplifier
Loudhearing
and
Tone ringing
MC with
EEPROM/
DTMF
Tone
ringer
1 (11)
TEMIC [ TEMIC SEMICONDUCTORS ]
