Memory Bypass System Mimicking Clock-to-Data Read Timing
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Solution Overview
Problem
Conventional memory bypass systems fail to accurately test on-chip timing by not incorporating normal memory timing during bypass read operations, leading to inaccurate results.
Innovation Solution
A bypass system and method that performs a synchronous pseudo-write-through operation, mimicking clock to data timing of a normal read operation by shadowing a write operation with test data in the read domain of a multiport register file, allowing for accurate timing testing without accessing the memory array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple interface (flip-flops, buffers, latches) is used to convey data directly from input port to output port, then device complexity is reduced and operation is simplified, but timing accuracy is lost because memory timing functions are completely bypassed
Solution Approach 1:
The patent creates a bypass path that copies the timing behavior of normal memory read operations. The bypass system replicates the clock-to-data timing characteristics of the memory array without actually accessing memory, allowing timing tests to be performed with both simplicity and accuracy.
Solution Approach 2:
The bypass system is segmented into distinct functional blocks: input latches for data capture, control logic for timing signal generation, and output buffers for data delivery. This segmentation allows each component to be optimized for its specific function while maintaining overall timing accuracy.
2Productivity
If data is provided directly through simple interfaces without memory array access, then operation speed is improved and energy consumption is reduced, but the timing characteristics of actual memory reads are not tested
Solution Approach 1:
The bypass path copies the temporal characteristics of memory read operations. Control logic generates clock signals and timing cues that replicate the timing behavior of actual memory reads, ensuring that timing tests remain valid while avoiding the slower memory access path.
Solution Approach 2:
Control logic acts as an intermediary between the simple bypass interface and the timing requirements of memory operations. It translates simple data passage into timing-accurate operations by generating appropriate clock signals and control cues that mimic real memory read timing.
3Ease of operation
If conventional bypass systems are used that completely bypass memory functions, then ease of operation is improved, but the ability to test on-chip timing accurately is degraded
Solution Approach 1:
The system copies the timing behavior of memory operations into the bypass path. Input latches capture data at the same timing points as memory reads, and control logic reproduces the clock-to-data timing relationships, allowing accurate timing measurements without complex memory access operations.
Solution Approach 2:
The bypass system performs timing self-testing by internally generating and measuring its own timing characteristics. Control logic generates clock signals and monitors the timing of data passage through the bypass path, enabling self-verification of timing accuracy without external test equipment.
Data Source
AI summary
A bypass system and method that mimics read timing of a memory system which includes a self-timing circuit and a sense amplifier. When prompted, the self-timing circuit initiates the sense amplifier to evaluate its differential input. The bypass system includes a memory controller that is configured to provide a bypass enable, to prompt the self-timing circuit, and to disable normal read control when a bypass read operation is indicated. A bypass latch latches an input data value, converts the input data value into an input complementary pair, and provides the complementary pair to the differential input of the sense amplifier. The sense amplifier, when initiated, evaluates the input complementary pair after its self-timing period and provides an output data value. The bypass latch and self-timing circuit may operate synchronous with a read clock in a read domain of the memory for more accurate memory read timing.