Power Circuit Board ChipsU209B-M Monolithic Integrated Control Circuitboard
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Power Circuit Board Chips U209B Monolithic Integrated Control Circuitboard
Monolithic Integrated Feature Phone Circuit Description The µc controlled telephone circuit U4090B is a linear integrated circuit for use in feature phones, answering machines and fax machines. It contains the speech circuit, tone ringer interface with dc/dc converter, sidetone equivalent and ear protection rectifiers. The circuit is line powered and contains all components necessary for amplification of signals and adaptation to the line. An integrated voice switch with loudspeaker amplifier allows loudhearing or handsfree operation. With an anti-feedback function, acoustical feedback during loudhearing can be reduced significantly. The generated supply voltage is suitable for a wide range of peripheral circuits.
Features DC characteristic adjustable Transmit and receive gain adjustable Symmetrical input of microphone amplifier Anti-clipping in transmit direction Automatic line loss compensation Symmetrical output of earpiece amplifier Built-in ear protection DTMF and MUTE input Adjustable sidetone suppression independent of sending and receiving amplification Speech circuit with two sidetone networks Built-in line detection circuit Integrated amplifier for loudhearing operation Anti-clipping for loudspeaker amplifier Improved acoustical feedback suppression Power down
Benefits Savings of one piezo electric transducer Complete system integration of analog signal processing on one chip Very few external components
Applications
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 = RSENSE CIND (RDC R30) / (RDC + R30)In order to improve the supply during worst case operating conditions two PNP current sources - IBOPT and IMPSOPT - hand an extra amount of current to the supply voltages, when the NPNs in parallel are unable to conduct current.
A flowchart for the control of the current sources (figure 5) shows, how a priority for supply VMPS is achieved.
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Product Tags: electronic chip board electronic components ic |
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