Transmitter DAC Current-Cell Control for Common-Mode Voltage
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Solution Overview
Problem
Conventional gigabit transmitters lack efficient power saving techniques, particularly in managing common-mode voltage, which leads to increased power consumption and inefficient operation in class-AB, class-B, and class-A modes, as existing methods fail to effectively suppress common-mode voltage variations.
Innovation Solution
A method is introduced that involves configuring current cells within a transmitter's DAC to operate in different modes by identifying and logically ORing phase control signals from adjacent cells, optimizing power savings while minimizing common-mode voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current cells are operated in class-AB or class-B mode to save power, then power consumption is reduced, but common-mode voltage variations increase
Solution Approach 1:
The patent applies preliminary action by activating current cells before the actual data transmission phase begins. The control circuit activates idle current cells in advance during a setup period, ensuring they are ready to contribute to maintaining stable common-mode voltage when transmission starts, thereby preventing voltage variations without compromising power savings during actual data transmission.
2Loss of energy
If idle output cells are operated in lower standby current to save power, then power consumption is reduced, but common-mode voltage control becomes difficult
Solution Approach 1:
The patent implements feedback by using a control circuit that continuously monitors the common-mode voltage level and dynamically adjusts the activation state of idle current cells based on the monitored voltage. This closed-loop feedback mechanism ensures that common-mode voltage remains stable while allowing idle cells to operate in low-power standby mode, resolving the contradiction between power savings and voltage control ease.
3Stability of the object's composition
If class-A mode is used to maintain constant common-mode current, then common-mode voltage stability is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by transitioning from the static class-A mode (where all cells are always active) to a dynamic control scheme. The control circuit dynamically adjusts which current cells are active based on real-time common-mode voltage conditions, allowing the system to achieve voltage stability similar to class-A mode while consuming less power by keeping idle cells in standby mode when conditions permit.
Data Source
AI summary
Provided is a method and system for controlling current characteristics in a transceiver having a transmitter. The method includes identifying a phase control signal from an adjacent current cell preceding the particular current cell in time and logically ORing the phase control signal from the preceding cell with a phase control signal from the particular current cell.