Semiconductor Output Circuit With Frequency-Based Swing Control
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Solution Overview
Problem
Conventional semiconductor output circuits experience jitter due to limited swing width of output signals, particularly at high frequencies, caused by high capacitance at the output node, which restricts the voltage swing and affects signal quality.
Innovation Solution
An output circuit with a signal selector and an output level controller that detects the frequency characteristics of the output signal and adjusts the voltage level to reduce swing width, ensuring that low-frequency signals are raised to a higher voltage level and lowered to a lower voltage level, thereby reducing the difference in swing width between low and high frequency signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high capacitance is present at the output node, then the circuit can drive high-frequency signals, but the swing width of the output signal is limited
Solution Approach 1:
The output level controller pre-adjusts the voltage level of the output signal before it reaches the high-capacitance node. By preliminarily controlling the voltage level based on frequency detection, the signal maintains adequate swing width even when driving high-frequency signals, thus resolving the contradiction between speed and swing width.
2Reliability
If the swing width of low-frequency signals is large, then the signal has sufficient voltage margin, but jitter increases
Solution Approach 1:
The output level controller dynamically adjusts the voltage level of the output signal based on the detected frequency characteristics. For low-frequency signals, it reduces the voltage level to minimize unnecessary swing and reduce jitter, while for high-frequency signals, it maintains adequate swing width. This dynamic adjustment resolves the contradiction between signal quality and jitter.
3Device complexity
If the voltage level of output signals is not adjusted, then the circuit structure remains simple, but the swing width difference between low and high frequency signals causes performance degradation
Solution Approach 1:
The patent introduces an output level controller that changes the voltage level parameter of the output signal based on frequency detection. This parameter change allows the circuit to optimize performance for different frequency ranges, resolving the contradiction between simple structure and reliable performance by adding only the necessary control functionality.
Data Source
AI summary
An output circuit of a semiconductor device includes a signal selector configured to receive first and second input data signals and sequentially outputting the first and second input data signals in response to a phase signal; and an output level controller configured to control a voltage level of an output signal of the signal selector based on the first and second input data signals.