Segmented Switched-Current Line-Driver Power Reduction
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Solution Overview
Problem
Current differential switched-current line drivers consume excessive power due to unnecessary output current, especially when supply voltages decrease, and face challenges in maintaining common-mode levels during drive and pre-emphasis changes, leading to high power consumption and potential level shifts.
Innovation Solution
A method to reduce power consumption by determining the required differential output current during a training phase and eliminating redundant common-mode current after training, using a segmented current driver with cells that can be controlled to direct, split, or disable current, maintaining differential current while minimizing total output current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a complementary switched-current driver is used to achieve differential current driving, then speed and impedance continuity are improved, but power consumption increases significantly
Solution Approach 1:
The current driver is divided into multiple controllable current segments (first current source and second current source) that can be independently controlled. This segmentation allows the system to deliver only the necessary differential current while eliminating redundant common-mode current, thereby reducing overall power consumption while maintaining signal speed and impedance continuity.
2Use of energy by moving object
If supply voltages decrease, then power consumption is reduced, but maintaining common-mode levels becomes difficult and power consumption increases again
Solution Approach 1:
The current driver employs dynamic control of the current sources based on the required differential output current. The control circuit adjusts the current sources dynamically to maintain proper common-mode levels while delivering the necessary differential signal, allowing the system to adapt to varying supply voltages and signal requirements without compromising reliability or increasing power consumption.
3Device complexity
If maximum output swing is limited, then driver complexity is reduced, but low-frequency content is attenuated instead of boosting high-frequency content
Solution Approach 1:
The system changes the parameter of current distribution by controlling the ratio of the first and second current sources. This allows the driver to maintain a limited output swing while adjusting the frequency response characteristics. By dynamically adjusting current parameters, the system can boost high-frequency content through pre-emphasis without requiring increased output swing or adding complex filtering circuits.
Data Source
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AI summary
A differential switched-current line-driver implements a method to reduce power consumption by eliminating output current that does not contribute to the required differential output signal. This output current is used for example during a training phase, and the current elimination can take place after the training phase is complete.