Command Buffer Circuit for Single- and Multi-Rank Memory
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Solution Overview
Problem
Conventional command buffer circuits for semiconductor apparatuses are specific to either single-rank or multi-rank structures, limiting their adaptability and requiring separate designs for different rank configurations, and often utilize multiple clock and impedance calibration signals even in multi-rank structures.
Innovation Solution
A command buffer circuit design that includes multiple buffers and a control signal generation block to selectively output command control signals based on a rank control signal, allowing the use of a single clock enable signal and a single impedance calibration signal across both single-rank and multi-rank structures, and incorporating a chip selection method for flexible operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a command buffer circuit is designed specifically for single-rank or multi-rank structure, then the circuit can be simplified for that specific structure, but the circuit cannot be used in other rank structures
Solution Approach 1:
The command buffer circuit is designed with dual functionality to support both single-rank and multi-rank structures. The circuit includes a first buffer for single-rank operation and a second buffer for multi-rank operation, with a selection mechanism that allows the same circuit to adapt to different rank configurations based on control signals.
Solution Approach 2:
The circuit incorporates dynamic selection capability through a selection signal that switches between the first buffer and second buffer based on the rank structure configuration. This dynamic switching allows the circuit to adapt its behavior and configuration according to whether it is operating in single-rank or multi-rank mode.
2Ease of operation
If multiple clock enable signals and impedance calibration signals are used in multi-rank structure, then each rank can be controlled independently, but the circuit complexity increases
Solution Approach 1:
The circuit merges the functionality of multiple buffers into a unified structure with shared components. The first and second buffers share common circuit elements and control logic, allowing independent rank control through signal selection rather than through completely separate buffer circuits.
Solution Approach 2:
A selection signal acts as an intermediary that routes control between the first buffer and second buffer based on the operational mode. This intermediary mechanism enables independent control of different ranks without requiring completely separate buffer circuits for each rank.
3Reliability
If separate command buffer circuits are designed for single-rank and multi-rank structures, then each circuit is optimized for its specific structure, but the overall design time and resource requirements increase
Solution Approach 1:
The invention creates a universal command buffer circuit that incorporates both single-rank and multi-rank functionality within a single design. The circuit includes all necessary buffer elements and selection logic to support both operational modes, eliminating the need for separate optimized designs for each rank structure.
Solution Approach 2:
The unified circuit is segmented into functional blocks (first buffer, second buffer, selection logic) that can be independently configured based on the operational mode. This segmentation allows the circuit to maintain optimized performance for both single-rank and multi-rank operations while using a single integrated design.
Data Source
AI summary
A command buffer circuit of a semiconductor apparatus includes a first buffer configured to receive a first command signal and generate a first command control signal, a second buffer configured to receive a second command signal and generate a second command control signal, a second block configured to select and output the first command control signal or the second command control signal in response to a rank control signal, and a control signal generation block configured to generate the rank control signal in response to a single rank signal and a chip select signal.