Switchable Termination Driver Circuit for Long-Distance Signaling
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Solution Overview
Problem
Current driver circuits for high-speed communication, such as CML and NMOS Push Pull, face challenges in achieving large amplitude signal output for long distance transmission while maintaining low power consumption, particularly in applications like sensor networks where medium to long distance data transmission is required.
Innovation Solution
A driver circuit comprising a current drive circuit and a termination resistance circuit connected in parallel, where the termination resistance is connected to the transmission line only when the current drive circuit outputs current, allowing for efficient signal transmission with reduced power consumption by matching the termination resistance to the transmission line's characteristic impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If CML is used as a driver circuit for high-speed communication, then signal transmission speed is improved, but current consumption increases due to through-current flow
Solution Approach 1:
The patent extracts the termination resistance from the continuous path and makes it switchable, so that it is only connected during signal transmission. This eliminates the through-current problem of CML while maintaining high-speed transmission capability when needed.
Solution Approach 2:
The patent introduces a switch to dynamically control the connection state of the termination resistance. The termination resistance is connected only when a signal is transmitted and disconnected otherwise, transforming the static CML structure into a dynamic one that adapts to transmission needs.
2Use of energy by moving object
If NMOS Push Pull is used to reduce power consumption, then current consumption decreases by eliminating through-current, but signal amplitude is limited by Vgs-Vth of Push NMOS making it unsuitable for long distance transmission
Solution Approach 1:
The patent merges the advantages of NMOS Push Pull (low power consumption) with the benefits of termination resistance (improved signal amplitude). By combining these two approaches with a switchable termination resistance, the patent achieves both low power consumption and sufficient signal amplitude for long-distance transmission.
Solution Approach 2:
The patent uses a dynamic switch to control the termination resistance connection, allowing the system to achieve large signal amplitude when needed while maintaining low power consumption during idle periods. This dynamic control resolves the amplitude limitation of static NMOS Push Pull circuits.
3Reliability
If termination resistance is always connected in CML to match impedance, then signal transmission quality is improved, but current wastage increases due to continuous through-current flow
Solution Approach 1:
The patent extracts the termination resistance from the continuous current path and makes it switchable. This allows impedance matching and signal quality improvement during transmission while eliminating continuous current wastage when no signal is being transmitted.
Solution Approach 2:
The patent implements periodic connection and disconnection of the termination resistance based on signal transmission needs. The resistance is connected periodically only when a signal is transmitted, rather than being continuously connected, thus reducing energy loss while maintaining transmission quality.
Data Source
AI summary
The present technology relates to a driver circuit, a control method therefor, and a transmission/reception system that enable implementation of a large amplitude signal output required for long distance transmission with low power consumption. The driver circuit includes: a current drive circuit that outputs a predetermined current; and a termination resistance circuit connected in parallel with the current drive circuit, in which the termination resistance circuit connects a termination resistance to a transmission line when the current drive circuit outputs a current, and disconnects the termination resistance from the transmission line when the current drive circuit does not output the current. The present technology can be applied to, for example, a driver circuit that outputs a signal to a long distance transmission line, and the like.