Thin Film Resistor Non-Volatile Memory for Low Voltage Programming
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Solution Overview
Problem
Existing non-volatile digital memories based on fuses or anti-fuses require high voltages and currents for programming, which are not compatible with standard circuit supply voltages, making them difficult to integrate into integrated circuits for post-packaging circuit trimming.
Innovation Solution
A non-volatile digital memory using thin film resistors that can be programmed and read by passing a current through them to reduce their sheet resistance, with a control circuit for data storage and comparison with a reference signal, allowing for low-voltage programming and reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuses or anti-fuses are used for non-volatile data storage, then data storage is achieved, but high voltages and currents are required for programming which are not compatible with standard circuit supply voltages
Solution Approach 1:
The patent changes the programming mechanism from high-voltage fuse/anti-fuse processes to low-voltage current-induced resistance change processes. By using thin film resistors that undergo resistance modification through controlled current passage, the system achieves non-volatile storage at standard supply voltages, resolving the contradiction between reliable storage and voltage compatibility.
2Reliability
If high voltages and currents are used for programming fuses or anti-fuses, then non-volatile storage is achieved, but integration into integrated circuits becomes difficult
Solution Approach 1:
The patent transforms the programming parameters from high-voltage/high-current fuse processes to low-voltage current-controlled resistance changes. This parameter transformation enables direct integration with standard CMOS circuits, eliminating the need for dedicated high-voltage test pins and complex external programming equipment.
Solution Approach 2:
The thin film resistor-based memory structure serves multiple functions: it provides non-volatile storage, is compatible with standard CMOS supply voltages, and can be programmed and read through standard circuit operations. This multi-functionality simplifies integration by eliminating specialized programming infrastructure.
3Device complexity
If standard CMOS supply voltages are used for programming, then ease of integration is improved, but sufficient programming current to modify resistor state cannot be achieved
Solution Approach 1:
The patent employs dynamic current control during the programming process. By applying controlled current pulses through the thin film resistor, the system temporarily creates conditions sufficient for resistance modification, then returns to normal operating conditions. This dynamic approach enables programming at standard voltages without requiring continuously high power levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the implementation of a digital non-volatile memory with low surface area and compatible programming voltages, suitable for standard CMOS technology, facilitating efficient circuit trimming and data storage with reduced sheet resistance.
Implementation Method 1
programming a plurality of thin film resistors with a plurality of bits of data by passing a current through at least one of the thin film resistors to reduce its sheet resistance
Implementation Method 2
reading the plurality of bits of data stored by the thin film resistors by generating an electrical signal associated with each thin film resistor and comparing each electrical signal with a reference signal
Data Source
AI summary
A non-volatile digital memory includes: a plurality of thin film resistors; and a control circuit adapted to: program, during a first programming phase, the thin film resistors with a plurality of bits of data by passing a current through at least one of the thin film resistors to reduce its resistance; and read, during a restoration phase, the plurality of bits of data stored by the thin film resistors by generating an electrical signal associated with each thin film resistor and comparing each electrical signal with a reference signal.