Phase Change Memory Voltage Generator Clock Pulse Width Control
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Solution Overview
Problem
Phase change memory devices face inefficiencies in charge pumping due to insufficient pulse width of the boosting clock signal, leading to charge loss and degraded performance.
Innovation Solution
A phase change memory device with a voltage generator that produces a modified clock signal with a constant pulse width, ensuring sufficient pulse width for the pump operation, even during low sink current conditions, by comparing a divided voltage to a reference voltage and generating a pump enable signal to maintain consistent operating voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump circuit uses a boosting clock signal with constant pulse width to generate operating voltage, then the charge pumping efficiency is improved, but the device complexity increases due to the need for additional clock signal modification circuitry
Solution Approach 1:
The patent applies preliminary action by modifying the clock signal pulse width in advance before it reaches the pump circuit. The clock signal is adjusted to have a sufficient pulse width that ensures the pump circuit can complete its charging operation fully, preventing charge loss that would otherwise occur during mode transitions. This pre-modification eliminates the need for complex real-time adjustments during pump operation.
Solution Approach 2:
The patent introduces an intermediary element - a clock signal modification circuit - that acts as a mediator between the control system and the pump circuit. This intermediary modifies the clock signal characteristics (pulse width) to ensure proper pump operation without requiring direct complex control of the pump circuit itself, thereby reducing overall system complexity while improving efficiency.
2Device complexity
If the boosting clock signal has insufficient pulse width, then the device complexity is reduced, but charge loss occurs and programming voltage application is degraded
Solution Approach 1:
The patent prevents charge loss by taking preliminary action - modifying the clock signal pulse width before the pump operation begins. By ensuring the clock signal has sufficient pulse width in advance, the pump circuit is given adequate time to complete its charging function, thereby preventing the charge loss that would occur with insufficient pulse width while avoiding complex real-time control mechanisms.
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
This solution enhances charge pumping efficiency by preventing charge loss and maintaining effective programming voltage application to phase change memory cells, thereby improving device performance.
Implementation Method 1
A pump circuit may operate on a power supply voltage to generate a desired operating voltage, which may be higher than the power supply voltage
Data Source
AI summary
A phase change memory device including a voltage generator that generates an operating voltage by generating at least one modified clock signal, a pulse width of which is maintained constant for at least one clock cycle in response to a pump enable signal being enabled, from at least one reference clock signal, and performing a pump operation on a power supply voltage according to the at least one modified clock signal; and a memory cell array that includes a plurality of phase change memory cells connected between word lines and bit lines. The operating voltage is applied to the memory cell array so as to perform a data access operation.