Reference Current Generator Slope Control for NVM Sensing
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Solution Overview
Problem
Conventional non-volatile memory reference current generators fail to provide accurate storage state judgments due to misjudgment caused by significant variations in supply voltage, especially when operating within a wide voltage range of 1.7V to 5.75V, leading to incorrect sensing of memory cell states.
Innovation Solution
A novel reference current generator system comprising a control voltage generation circuit, a current path selecting circuit, and a mirroring circuit that adjusts the reference current slope based on the characteristics of the memory cell, allowing the sensing circuit to correctly determine storage states by providing reference currents with varying slopes in response to different supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional reference current generator is used, then the circuit structure is simple, but the sensing accuracy deteriorates due to misjudgment caused by supply voltage variations
Solution Approach 1:
The reference current generator dynamically adjusts the reference current slope based on the detected supply voltage. The circuit transitions from a static reference current approach to a dynamic one where the reference current changes proportionally with supply voltage variations, thereby maintaining accurate sensing across different voltage conditions.
Solution Approach 2:
The invention changes the parameter of reference current slope to adapt to supply voltage variations. By adjusting the slope parameter based on detected voltage levels, the system maintains optimal sensing accuracy without requiring a completely redesigned circuit architecture.
2Measurement precision
If the reference current is fixed, then the circuit operation is simple, but the sensing accuracy deteriorates when supply voltage varies within the wide range of 1.7V to 5.75V
Solution Approach 1:
The reference current generator incorporates a feedback mechanism that detects the supply voltage level and uses this information to adjust the reference current slope accordingly. This closed-loop approach ensures that the reference current adapts to the actual operating conditions, maintaining accurate sensing across the wide voltage range.
Solution Approach 2:
The system transitions from a static reference current to a dynamic one that automatically adjusts its slope based on supply voltage variations. This dynamic adaptation enables the circuit to maintain optimal performance across different operating conditions without manual intervention.
3Stability of the object's composition
If a bandgap reference circuit is added to stabilize reference current, then the reference current stability improves, but the device complexity increases and the slope adjustment capability is lost
Solution Approach 1:
Instead of using a bandgap reference circuit to stabilize the reference current, the invention changes the approach by adjusting the reference current slope parameter based on supply voltage detection. This parameter-based adaptation achieves stability without the complexity of a bandgap circuit.
Solution Approach 2:
The invention extracts the essential function of voltage compensation from the complex bandgap reference circuit and implements it through a simpler mechanism that detects supply voltage and adjusts the reference current slope accordingly, removing unnecessary circuit complexity.
Data Source
AI summary
A non-volatile memory receives a supply voltage. The non-volatile memory includes a reference current generator and a sensing circuit. The reference current generator provides a reference current to the sensing circuit. The reference current generator includes a control voltage generation circuit, a current path selecting circuit and a mirroring circuit. The control voltage generation circuit receives a control signal and generates a control voltage according to the control signal. The current path selecting circuit generates the reference current. A current input terminal of the mirroring circuit receives the reference current. If the control signal is set as a first value, the reference current is changed at a first slope in a range of the supply voltage. If the control signal is set as a second value, the reference current is changed at a second slope in the range of the supply voltage.