Data Output Driver Slew Rate Control Under PVT Variation
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Solution Overview
Problem
Conventional data output driving circuits lack the capability to control the slew rate of data signals effectively under variations in process/voltage/temperature (PVT) conditions, leading to potential data loss and limited operational frequency.
Innovation Solution
A data output driving circuit with a slew rate control signal generating unit that adjusts the slew rate based on variable on-die termination codes, using a combination of registers, adders, decoders, and selecting units to generate and update slew rate control signals, and drivers with slew rate adjusting units to maintain optimal data output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional data output driving circuit is used without slew rate control, then the circuit structure is simple, but the slew rate cannot be optimized under PVT variations causing data loss and limited operational frequency
Solution Approach 1:
The patent implements dynamic slew rate control by making the driver circuit parameters adjustable based on operational conditions. The slew rate is dynamically optimized by selecting different resistance values (Rup, Rdn) and capacitance values (Cup, Cdn) according to PVT variations, allowing the circuit to adapt its performance characteristics in real-time rather than being fixed
Solution Approach 2:
The patent changes physical parameters (resistance and capacitance values) to optimize slew rate under different operational conditions. By providing multiple sets of resistance and capacitance values that can be selectively activated, the system adjusts the slew rate parameter to match varying process, voltage, and temperature conditions, thereby preventing data loss and expanding operational frequency range
2Reliability
If slew rate control is added to optimize data output, then data loss is prevented and operational frequency is expanded, but the circuit complexity increases with additional control units
Solution Approach 1:
The patent achieves multi-functionality by integrating slew rate control capabilities into the existing driver circuit structure. The same driver circuit that performs data output also performs slew rate control when activation signals are applied, allowing one circuit to serve multiple functions (data driving and slew rate optimization) without requiring completely separate control systems
Solution Approach 2:
The patent implements partial control by providing multiple sets of control signals (first through fourth activation signals) that can be selectively applied based on operational needs. Not all control mechanisms are activated simultaneously or always, but only when needed to optimize slew rate under specific PVT conditions, reducing unnecessary circuit activity and complexity
Data Source
AI summary
A data output driving circuit capable of optimizing a slew rate of data according to the variation of operational conditions and a method for controlling a slew rate thereof includes a slew rate control signal generating unit configured to generate slew rate control signals by using a code signal, and a plurality of drivers configured to output data by driving the data at a slew rate set according to the slew rate control signals.