Interval-Based Duty Cycle Correction for Memory Clock Sampling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Process-voltage-temperature (PVT) variations and silicon interface impacts lead to duty cycle distortions in clock signals between controllers and memory dies, causing sampling errors in memory applications.
Innovation Solution
A duty cycle correction system comprising a measurement circuit and an output circuit that measures average time interval durations of input signals and generates output signals with corresponding time intervals to correct duty cycle distortions, using a combination of detection circuits, ramp generation circuits, and drive strength control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If duty cycle correction is implemented using traditional schemes, then duty cycle accuracy is improved, but circuit complexity and power consumption increase
Solution Approach 1:
The duty cycle correction is segmented into interval-based operations where the clock signal is divided into multiple time intervals. The circuit processes each interval separately using segmented logic paths for high and low state durations, allowing complex correction functionality to be broken down into manageable segments that reduce overall circuit complexity.
Solution Approach 2:
The duty cycle correction circuit uses self-service mechanisms where the measurement of time intervals automatically feeds into the correction logic without requiring external control. The circuit self-regulates by comparing accumulated high and low state durations and automatically adjusting the output duty cycle based on these measurements, eliminating the need for complex external control logic.
2Manufacturing precision
If duty cycle correction is implemented using traditional schemes, then duty cycle accuracy is improved, but power consumption increases
Solution Approach 1:
The duty cycle correction operates using periodic action by measuring time intervals in discrete cycles. The circuit accumulates high and low state durations over periodic intervals, then applies corrections based on these periodic measurements. This periodic operation mode allows the circuit to remain in low-power states between measurements while maintaining accurate duty cycle correction functionality.
Solution Approach 2:
The circuit performs self-service by automatically measuring and correcting duty cycle without requiring continuous external power-intensive control signals. The self-service mechanism enables the circuit to maintain correction functionality while consuming minimal power by only activating correction logic when duty cycle adjustment is actually needed based on measured intervals.
3Measurement precision
If interval-by-interval duty cycle correction is implemented, then sampling accuracy is improved, but measurement complexity increases
Solution Approach 1:
The time measurement is segmented into discrete intervals corresponding to clock signal cycles. Each interval is measured separately using dedicated counter logic that tracks high and low state durations independently. This segmentation approach improves sampling accuracy by capturing precise interval boundaries while managing measurement complexity through modular interval processing.
Solution Approach 2:
The patent introduces intermediary elements such as time interval counters and duration accumulators that mediate between the raw clock signal and the duty cycle correction logic. These intermediaries simplify measurement by converting complex time interval analysis into manageable count values that can be easily processed and compared, reducing the overall measurement complexity.
Data Source
AI summary
A duty cycle correction system corrects for duty cycle distortion by measuring average time interval durations of consecutive intervals of an input signal. The system generates complementary ramp signals that have cross-points indicating midpoints of the intervals, and detects those cross-points. An output circuit of the duty cycle correction system generates an output signal that performs rising and falling transitions in response to the detected cross-points.