Memory Sensing Circuit Using a Global Counter Instead of Local ADCs
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Solution Overview
Problem
Conventional in-memory computing devices face challenges due to the physical size and power consumption issues caused by the use of local analog-to-digital converters (ADCs) in each local sensing circuit, which occupy significant space and consume excessive power.
Innovation Solution
Implementing a global counter that provides a count value to each sensing circuit, eliminating the need for local ADCs and using a local detector circuit to generate a trigger signal based on the difference between detected and reference voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If local analog-to-digital converters (ADCs) are implemented in each local sensing circuit, then accurate current sensing and conversion to digital signals is achieved, but the device occupies excessive physical space and consumes excessive power
Solution Approach 1:
Multiple local sensing circuits share a single global counter instead of each having its own local ADC. The global counter is used sequentially by different sensing circuits to convert analog current measurements to digital values, eliminating the need for multiple redundant ADC components and reducing overall device area.
Solution Approach 2:
The global counter serves multiple functions: it acts as the ADC for multiple different sensing circuits, performs sequential conversions for different bit line pairs, and provides a universal conversion mechanism that replaces numerous specialized local ADCs with a single multi-functional component.
2Measurement precision
If local analog-to-digital converters (ADCs) are implemented in each local sensing circuit, then accurate current sensing and conversion to digital signals is achieved, but the device consumes excessive power
Solution Approach 1:
Multiple local sensing circuits share a single global counter instead of each having its own local ADC. The global counter is used sequentially by different sensing circuits to convert analog current measurements to digital values, eliminating the need for multiple redundant ADC components and reducing overall device area.
Solution Approach 2:
The global counter serves multiple functions: it acts as the ADC for multiple different sensing circuits, performs sequential conversions for different bit line pairs, and provides a universal conversion mechanism that replaces numerous specialized local ADCs with a single multi-functional component.
3Ease of operation
If each local sensing circuit includes a local ADC, then independent analog-to-digital conversion is achieved, but the device complexity increases
Solution Approach 1:
Multiple local sensing circuits share a single global counter instead of each having its own local ADC. The global counter is used sequentially by different sensing circuits to convert analog current measurements to digital values, eliminating the need for multiple redundant ADC components and reducing overall device area.
Data Source
AI summary
A circuit is provided. The circuit includes an array of memory cells including a plurality of bit lines and a plurality of word lines, sensing circuits configured to sense a difference between first and second currents on respective bit lines in selected bit lines and to produce outputs for the selected bit lines as a function of the difference, and a global counter configured to continuously provide a count value to each of the sensing circuits in dependence on a clock signal. Each sensing circuit, of the sensing circuits, can produce an output in dependence on (i) the difference between the first and second currents and (ii) a stored count value received from the global counter, the count value being stored in dependence on a value of the difference between the first and second currents.