Non-Volatile Memory Read Current Control Circuit
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Solution Overview
Problem
Non-volatile memory technologies, particularly EEPROMs, face challenges in maintaining reliable read operations across a wide range of supply voltages, leading to issues with access time and current control, especially at low voltages where parasitic capacitive coupling and transistor resistance affect read current accuracy.
Innovation Solution
A control circuit that determines a model current based on the supply voltage and compares it to a reference current to generate a control signal, adjusting the read current to the lowest value between a fraction of the model current and the reference current, ensuring stable read operations across varying voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the read current is increased to achieve rapid access time at high supply voltage, then access time is improved, but power consumption increases and current control stability deteriorates
Solution Approach 1:
The patent applies dynamics by making the read current adjustable rather than fixed. The control circuit dynamically adapts the read current level based on the detected supply voltage, allowing the system to optimize between speed and power consumption for different operating conditions. This resolves the contradiction by enabling rapid access at high voltages while maintaining controlled power consumption at low voltages.
Solution Approach 2:
The patent changes the parameter of read current based on supply voltage conditions. The control circuit detects the supply voltage level and adjusts the read current accordingly - using higher current at high voltages for fast access and lower current at low voltages for power efficiency. This parameter adaptation resolves the contradiction between speed and energy loss.
2Loss of energy
If the read current is decreased to reduce power consumption at low supply voltage, then power consumption is improved, but access time increases and read reliability deteriorates
Solution Approach 1:
The control circuit dynamically adjusts the read current based on supply voltage detection. At low supply voltages, it reduces the read current to minimize power consumption while maintaining sufficient current for reliable operation. This dynamic adaptation resolves the contradiction between power consumption and access time by optimizing current for each voltage condition.
Solution Approach 2:
The patent changes the read current parameter according to supply voltage levels. At low voltages, the control circuit selects a lower current value to reduce power consumption, while ensuring the current remains adequate for reliable cell reading. This parameter change resolves the contradiction between energy loss and speed.
3Reliability
If a fixed high read current is used to ensure reliable reading at low supply voltage, then read reliability is improved, but access time increases at high supply voltage and power consumption increases
Solution Approach 1:
The control circuit dynamically adapts the read current level based on detected supply voltage. At low voltages, it uses higher current to ensure reliable reading despite increased transistor resistance. At high voltages, it reduces current since transistors are more conductive, thereby improving access time and reducing power consumption. This dynamic adjustment resolves the contradiction between reliability and speed.
Solution Approach 2:
The patent changes the read current parameter based on supply voltage conditions to maintain reliable operation across different voltage levels. The control circuit selects appropriate current values - higher at low voltages for reliability and lower at high voltages for speed optimization. This parameter adaptation resolves the contradiction between reliability and access time.
4Reliability
If the read current is increased to compensate for increased transistor resistance at low supply voltage, then read reliability is improved, but power consumption increases
Solution Approach 1:
The control circuit changes the read current parameter based on detected supply voltage levels. At low voltages where transistor resistance is higher, it increases current to maintain reliable reading. At high voltages where transistors are more conductive, it reduces current to minimize power consumption. This adaptive parameter change resolves the contradiction between reliability and energy loss.
Data Source
AI summary
In an embodiment, a method is provided for controlling a level of a read current in a non-volatile memory that is powered by a supply voltage includes. A model current representative of an actual current able to flow during a readout through a read path of the memory is determined based on the value of the supply voltage. The model current is compared to a reference current having a reference value. A control signal is generated. The control signal is to control the generation of the read current having a level equal to the lowest value between a fraction of the value of the model current and the reference value.