Balanced impedance method for differential signaling
AssigneeAnalog Devices, Inc.
InventorsMark SAYUK, Ronald KAPUSTA
Life of this patent
Estimating the term…
Abstract
A system and method for implementing a differential signaling driver with a common-mode voltage not equal to one half the power supply voltage using voltage-mode techniques. Embodiments of the present invention maintain balanced impedance at the signal output. In an embodiment, a driver may have multiple operating modes for each potential supply voltage or common-mode voltage. In an embodiment, each potential mode may involve configuring the driver by activating or deactivating switches or resistors in the driver and each potential mode may have different resistor values.
Claims10
A system comprising:
- a differential signaling driver having a plurality of variable resistors and a supply voltage, wherein the driver may be configured to develop a plurality of potential common-mode voltages such that at least one common-mode voltage deviates from one-half the supply voltage;
- and
- a controller to select one of the potential common-mode voltages and to set the variable resistors in accordance with the selected common-mode voltage.
A system comprising:
- an analog source;
- an analog signal processor to convert an analog signal from the analog source into a digital signal and to transmit the digital signal using a voltage-mode differential signaling driver;
- and
- a digital signal processor to process the digital signal received from the voltage-mode differential signaling driver;
- wherein the voltage-mode differential signaling driver has a common-mode voltage that deviates from one-half of a supply voltage;
- wherein the resistor values are set such that the driver has balanced output impedance.
A method of configuring a voltage-mode differential driver comprising:
- selecting with a controller a supply voltage and a common-mode voltage, wherein the selected common-mode deviates from one half the supply voltage;
- activating with the controller a plurality of resistors in the driver to achieve the selected common-mode voltage;
- and
- selecting with the controller, values for the plurality of resistors to achieve the selected common-mode voltage;
- wherein the resistor values are set such that the driver has balanced output impedance.
A method comprising:
- selecting one of a plurality of modes for a differential signaling driver;
- activating at least one of a plurality of switches in the driver in accordance with the selected mode;
- activating at least one of a plurality of resistors in the driver in accordance with the selected mode;
- wherein the selected mode specifies a supply voltage and a common-mode voltage, the common-mode voltage deviates from one half the supply voltage;
- and
- wherein the selected mode specifies values for the plurality of resistors.
Dependencies are inferred from the claim text.