Bias Generator for Non-Volatile Memory Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-volatile memory circuits face challenges in generating stable wordline and bitline voltages due to process and temperature variations, requiring resource-intensive solutions that impact performance.
Innovation Solution
An integrated circuit with a bias generator that includes a bias replica circuit to generate wordline bias voltages and a cascode voltage generation circuit to generate bitline bias voltages, both compensated for temperature and process variations, allowing for low voltage memory operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current solutions are used to handle voltage variations due to temperature and process changes, then voltage stability is improved, but resource consumption increases and performance is impacted
Solution Approach 1:
The bias generator uses a feedback mechanism where the current through the replica memory array is automatically compared with a reference current, and the charge pump automatically adjusts the gate voltage to maintain equality between these currents. This self-regulating system compensates for temperature and process variations without requiring external control resources.
Solution Approach 2:
The system employs a feedback loop where the current through the replica memory array is continuously monitored and compared with a reference current. The difference between these currents controls the charge pump, which adjusts the gate voltage to maintain current equality, thereby stabilizing the voltage against temperature and process variations.
2Reliability
If temperature sensors and external monitoring are used to compensate for variations, then voltage stability is improved, but device complexity increases
Solution Approach 1:
The bias generator creates a simplified replica of the memory array operation using a replica memory array that mimics the electrical characteristics of the main array. This replica circuit allows the system to sense and compensate for process and temperature variations without requiring complex external sensors or monitoring circuits.
Solution Approach 2:
The replica memory array serves as an intermediary that translates temperature and process variations into current changes. This intermediary circuit allows the feedback mechanism to indirectly sense environmental variations and adjust the gate voltage accordingly, avoiding the need for direct temperature sensing.
3Power
If high analog supply voltage is used for wordline generation, then voltage generation capability is improved, but adaptability to low voltage operations is reduced
Solution Approach 1:
The charge pump dynamically adjusts the gate voltage based on the feedback from the current comparison. The voltage is not fixed but continuously adapted to maintain the required current equality condition, allowing the system to operate effectively across a range of supply voltages including low voltage digital ranges.
Solution Approach 2:
The system changes the gate voltage parameter dynamically in response to feedback signals. The charge pump modifies the voltage level according to the difference between the replica array current and reference current, enabling adaptation to different supply voltage conditions and process variations.
Data Source
AI summary
The present disclosure is directed to an integrated circuit that includes a non-volatile memory (NVM). The integrated circuit includes a bias generator that produces stable wordline and bitline voltages for a reliable read operation of the NVM. This disclosure is directed to low voltage memory operations of memory read, erase verify, and program verify. The present disclosure is directed to non-volatile memory circuits that can also operate at low supply voltages in digital voltage supply range.