Low-Swing Differential Output Driver for Wide-Range Supply Voltage
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Solution Overview
Problem
Low supply voltage in portable and mobile devices reduces noise immunity in signaling, making it challenging to maintain reliable communication, especially with differential signaling techniques.
Innovation Solution
An output driver with a voltage convertor, output stage, and biasing unit that can operate in either core device voltage mode or high voltage mode, converting input signals to produce differential output signals with a maximum voltage of either the core device voltage or a higher voltage, while ensuring the biasing current maintains a terminal-to-terminal voltage within the reliability limits of the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage is lowered to save power and reduce emitted radiation, then power consumption and radiation are reduced, but noise immunity in signaling deteriorates
Solution Approach 1:
The output driver dynamically switches between two operating modes: a low-voltage mode for power saving and a high-voltage mode for improved noise immunity. The circuit includes voltage-selectable output stages that can be configured to operate at either the core device voltage (low-voltage mode) or a higher voltage level (high-voltage mode), allowing adaptive optimization of both power consumption and signaling reliability based on operational requirements
Solution Approach 2:
The invention changes the voltage parameter of the output driver by providing selectable operating voltages. The output driver can operate at the core device voltage for normal operation or switch to a higher voltage for enhanced noise immunity during critical signaling operations. This parameter change is achieved through voltage-selectable output stages and biasing circuits that accommodate multiple voltage levels
2Device complexity
If a fixed voltage output driver is used, then the circuit design is simplified, but the adaptability to different voltage modes is reduced
Solution Approach 1:
The output driver is designed with universal functionality to operate in multiple voltage modes. The voltage-selectable output stages can be configured to operate at either the core device voltage or a higher voltage level, making the circuit adaptable to different operational requirements. This multi-functionality is achieved through shared circuit elements that can operate across different voltage ranges and selective activation of appropriate output stages
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances noise immunity and extends the operational lifetime of transistors by allowing the output driver to adapt to higher voltages, reducing the risk of operational failure and maintaining signal integrity in low-voltage environments.
Implementation Method 1
converting a maximum voltage of the input signals to a high voltage that is greater than the core device voltage
Implementation Method 2
generating a biasing current based upon the selected mode, wherein the biasing current is configured to produce a terminal-to-terminal voltage in an output stage and biasing unit that is less than a reliability voltage of the components
Data Source
AI summary
According to one general aspect, an output driver configured to drive output signals from a core device may include a voltage convertor, an output stage, and a biasing unit. In various embodiments, the output driver is configured to operate in either a core device voltage mode or a high voltage mode. In some embodiments, the voltage convertor may be configured to receive a pair of differential input signals from a core device, wherein a maximum voltage of the input signals is equivalent to a core device voltage, and convert the input signals to a pair of intermediate input signals. In one embodiment, when in high voltage mode, the maximum voltage of the intermediate input signals may be equivalent to a high voltage that is higher than the core device voltage. In some embodiments, the output stage configured to receive the intermediate input signals, and produce a pair of differential output signals having a maximum voltage of, based upon the operating mode of the output driver, either the core device voltage or the high voltage. In various embodiments, the biasing unit configured to provide a biasing current to the output stage, wherein the biasing current is configured to produce a desired common mode voltage within the output stage.