Conexant Systems, Inc.

Silicon Laboratories Inc.

Ketankumar B Patel

Thomas Grey Beutler

James B Skov

Faouzi Chaahoub

Transformer driven by data modulated signal provides isolated power. Outbound data is extracted from the data modulated signal received from the transformer. Inbound data received in isolated circuitry modulates the load presented to transformer. Inbound data perceived in non-isolated circuitry by sensing load experienced by the transformer.

Method and apparatus for conveying bidirectional data, power and timing signals using a single transformer

According to an embodiment, a DC driver circuit is coupled to a tip/ring line. The DC driver circuit includes a first capacitor coupled to a first switch where the first switch is coupled to an amplification circuit. An RC circuit is coupled to a second switch where the second switch is coupled to the amplification circuit. During a make state, the first and second switches are closed, causing the amplification circuit to draw current from the tip/ring line. During a break state, the first and second switches are open, preventing the amplification circuit from drawing current from the tip/ring line. The transition from the make state, during which a significant amount of current is drawn from the tip/ring line, to the break state, during which no current should be drawn from the tip/ring line, occurs at a rate that results in a significantly reduced voltage peak at the tip/ring line.

Circuit for reducing voltage peak in interfacing with a telephone line

According to a disclosed embodiment, the ideal magnitude and phase of an ideal impedance for interfacing a modem with a telephone line is determined. This ideal impedance can be determined in the presence of an external impedance load and associated circuitry, such as an ADSL modem and accompanying POTS splitter. Thereafter, a model for an interface circuit inside the modem is utilized to arrive at an appropriate impedance for an impedance network inside the interface circuit. As an example, the interface circuit can be a DAA circuit inside a V.90 modem. Then, a relationship between the ideal impedance and an input impedance of the impedance network is established. Thereafter, the impedance network is synthesized to that the relationship between the input impedance of the impedance network and the ideal impedance is in fact satisfied. The impedance network can be, for example, a circuit comprising at least one capacitor.

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Lake Forest, CA, United States of America

Ketankumar B Patel