CMOS Transmission Circuit With Charge-Unit Pre-Emphasis
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Solution Overview
Problem
Existing transmission circuits face challenges in maintaining signal quality due to charge injection and clock feed-through, leading to waveform distortion, and require multiple transmitters and clock delay circuits, which increase power dissipation and layout area, while failing to synthesize ideal emphasized signals.
Innovation Solution
A transmission circuit with an auxiliary circuit and charge units that inject different charges based on level transitions to compensate for non-ideal effects, allowing for pre-emphasis in a single transmitter with reduced power consumption and simpler layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two transmitters and a clock delay circuit are used to pre-emphasize the output signal, then the signal transmission quality is improved, but the power dissipation and layout area increase
Solution Approach 1:
The patent combines the functions of multiple transmitters and a clock delay circuit into a single transmitter by using charge units that are electrically connected to the output node. Each charge unit responds to level transitions in auxiliary signals and injects charges to pre-emphasize the output signal, eliminating the need for separate transmitters and delay circuits while maintaining signal transmission quality.
Solution Approach 2:
The single transmitter in the patent performs multiple functions: it generates output signals, provides pre-emphasis through charge units, and compensates for non-ideal factors all in one circuit. The charge units serve as multi-functional elements that detect level transitions, generate emphasis signals, and inject charges to improve signal quality without requiring additional dedicated circuits.
2Reliability
If two transmitters and a clock delay circuit are used to pre-emphasize the output signal, then the signal transmission quality is improved, but the layout area increases
Solution Approach 1:
The patent merges the layout requirements of two transmitters and a clock delay circuit into a single compact transmitter structure. The charge units are integrated within the single transmitter circuit, sharing common components and reducing the overall layout area while maintaining the pre-emphasis functionality needed for signal transmission quality.
Solution Approach 2:
The charge units are nested within the single transmitter structure, with each charge unit containing capacitor elements that are electrically connected to the output node. This nested arrangement allows the pre-emphasis functionality to be embedded within the transmitter itself, reducing the need for separate external circuits and minimizing layout area.
3Reliability
If a clock delay circuit is used to synthesize emphasized signals, then the pre-emphasis function is achieved, but an extra clock is required
Solution Approach 1:
The patent extracts the delay function from a separate clock delay circuit and integrates it directly into the charge units within the transmitter. The charge units respond to level transitions in auxiliary signals that are generated by the transmitter itself, eliminating the need for an external clock delay circuit and reducing device complexity.
Solution Approach 2:
The transmitter generates its own auxiliary signals and uses its internal charge units to provide the pre-emphasis function without requiring external clock signals. The system is self-sufficient, using its own output signals to trigger the charge units, which then inject charges to pre-emphasize the output, eliminating dependence on external clock delay circuits.
4Device complexity
If CMOS transistors are used in the transmitter, then the circuit is simple, but charge injection and clock feed-through occur causing waveform distortion
Solution Approach 1:
The patent converts the harmful effects of charge injection and clock feed-through into beneficial pre-emphasis. The charge units detect the level transitions caused by these non-ideal factors and respond by injecting charges that pre-emphasize the output signal. What was originally a source of waveform distortion is now utilized to enhance the signal quality by compensating for transmission line effects.
Solution Approach 2:
The charge units operate based on feedback from the level transitions in the auxiliary signals. When the auxiliary signals experience level transitions (caused by charge injection and clock feed-through), the charge units detect these transitions and respond by injecting appropriate charges to pre-emphasize the output signal, creating a feedback mechanism that converts non-ideal effects into quality improvement.
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
The solution effectively compensates for charge injection and clock feed-through, achieving improved signal transmission quality with enhanced rising and falling edges, and realizes pre-emphasis without increasing power consumption or layout complexity.
Implementation Method 1
at least a charge unit, each charge unit being electrically connected to the output node, and each charge unit being individually corresponding to one of the auxiliary signals. When a level transition occurs in the auxiliary signal corresponding to each charge unit, each charge unit is able to inject different charges in the output node according to the level transition trend, and couple the level of the auxiliary signal to the output node.
Data Source
AI summary
A transmission circuit and related method are disclosed. A transmitter in the transmission circuit has CMOS transistors as driving units for responding an input signal to drive an output signal at an output node, and each driving unit has a corresponding charge unit formed by a capacitor-connected MOS of a same type as that of the corresponding driving unit. Each charge unit is controlled by an auxiliary signal inverse to the input signal. When a level transition occurs in the input signal, the charge unit can compensate charge injection and clock feed-through caused by the driving unit at the output node, and form peaks for pre-emphasis. In this way, a better transmission property can be realized by using a simpler and low-power circuit design.