摘要:
A MOSFET-based, multi signal-switching circuit controllably passes analog/audio signals and digital signals through a common terminal to a single connector. Analog/audio signals are coupled through a single N-channel MOSFET analog signal switch which, when turned-ON, minimizes distortion of the analog/audio signal and capacitive loading to an adjacent, MOS-based or CMOS-based digital data signal switch. A respective turn-OFF circuit maintains its associated switch MOSFET turned OFF.
摘要:
A mode-dependent, battery-coupling switch for a subscriber line interface circuit (SLIC) selectively adjusts its current requirements to provide optimal current handling capability irrespective of the mode of operation of the SLIC. Where current demands of the SLIC are relatively minimal (e.g., on-hook idle mode), the bias is set at a relatively small, default value. During high current demand, such as ringing and off-hook signaling, the bias is set at a relatively large value, to maintain a low voltage drop across the battery-coupling switch.
摘要:
A subscriber line interface circuit has a battery-powered, high voltage analog section, that drives tip and ring lines of a subscriber loop, and a mixed signal (low voltage and digital signal processing) section, that monitors and controls the high voltage analog section. An input signal receiving unit of the high voltage analog section conditions input voice and low voltage signaling and ringing signals from the mixed signal section, for application to a dual mode, programmable gain, tip/ring amplifier coupled to the loop. A sense amplifier at the output of the tip/ring amplifier is through an auxiliary amplifier to an analog feedback monitor port for closing a loop to synthesize the circuit's output impedance.
摘要:
A mode-dependent, battery-coupling switch for a subscriber line interface circuit (SLIC) selectively adjusts its current requirements to provide optimal current handling capability irrespective of the mode of operation of the SLIC. Where current demands of the SLIC are relatively minimal (e.g., on-hook idle mode), the bias is set at a relatively small, default value. During high current demand, such as ringing and off-hook signaling, the bias is set at a relatively large value, to maintain a low voltage drop across the battery-coupling switch.
摘要:
A subscriber line interface circuit has a battery-powered, high voltage analog section, that drives tip and ring lines of a subscriber loop, and a mixed signal (low voltage and digital signal processing) section, that monitors and controls the high voltage analog section. An input signal receiving unit of the high voltage analog section conditions input voice and low voltage signaling and ringing signals from the mixed signal section, for application to a dual mode, programmable gain, tip/ring amplifier coupled to the loop. A sense amplifier at the output of the tip/ring amplifier is through an auxiliary amplifier to an analog feedback monitor port for closing a loop to synthesize the circuit's output impedance.
摘要:
A subscriber line interface circuit has a battery-powered, high voltage analog section, that drives tip and ring lines of a subscriber loop, and a mixed signal (low voltage and digital signal processing) section, that monitors and controls the high voltage analog section. An input signal receiving unit of the high voltage analog section conditions input voice and low voltage signaling and ringing signals from the mixed signal section, for application to a dual mode, programmable gain, tip/ring amplifier coupled to the loop. A sense amplifier at the output of the tip/ring amplifier is through an auxiliary amplifier to an analog feedback monitor port for closing a loop to synthesize the circuit's output impedance.
摘要:
A voltage regulator circuit arrangement limits the DC voltage applied to a tip and ring amplifiers of a subscriber line interface circuit (SLIC), each of which has a first polarity input coupled to a first current flow path to which a DC input (battery) voltage is coupled. A first current source supplies a first current derived via a low pass filter path from that flowing through the first current flow path to a second polarity input node of the tip amplifier, while a second current source supplies a similarly low pass filter path-derived second current to a second polarity input node of the ring amplifier. A voltage regulator is coupled with the first current flow path and is operative to regulate the voltage at the first polarity inputs of the tip and ring amplifiers to a regulated voltage value Vreg, so that the magnitudes of the first and second currents are based upon the regulated voltage value Vreg.
摘要:
A mode-dependent, battery-coupling switch for a subscriber line interface circuit (SLIC) selectively adjusts its current requirements to provide optimal current handling capability irrespective of the mode of operation of the SLIC. Where current demands of the SLIC are relatively minimal (e.g., on-hook idle mode), the bias is set at a relatively small, default value. During high current demand, such as ringing and off-hook signaling, the bias is set at a relatively large value, to maintain a low voltage drop across the battery-coupling switch.
摘要:
A CMOS-implemented transconductance amplifier has an input gain stage coupled to a CMOS output stage. The inverting input of the input gain stage is coupled to an input/output port to which an input voltage is coupled. The CMOS output stage has a first, transconductance CMOS transistor pair, whose source-drain paths are series-coupled between first and second outputs of the input stage. A second, transimpedance CMOS transistor pair have their source-drain paths series-coupled between first and second power supply terminals, and gate inputs coupled to outputs of the input stage. A third CMOS transistor pair is coupled in parallel with the second CMOS transistor pair to form a pair of current mirror stages. The current output is coupled to a common connection of the third CMOS pair.
摘要:
A voltage-coupling and loop current supply mechanism controllably turns on an output transistor within the tip amplifier circuitry portion of the speech amplifier to controllably apply a prescribed voltage to the telephone line during on-hook/standby mode. This controllably applied voltage serves as a source of loop current when the phone goes off-hook. The ring lead portion of the tip/ring wireline pair is connected to a controlled current sink, which is coupled to the output of a voltage regulator referenced to the battery voltage. This controlled current sink is used to sink a prescribed loop current from the tip/ring pair when the phone goes off-hook. When the phone goes off-hook and loop current is detected, the voltage-supply mechanism provided by the tip amplifier's output transistor is terminated, and the speech amplifier is placed in its normal speech amplifier mode.