Two Transistor Word Line Driver Power Reduction
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Solution Overview
Problem
Existing two-transistor (2T) word line drivers in memory integrated circuits are complex and consume excessive power, with issues such as leakage current and stringent power requirements, particularly in decreasing die sizes.
Innovation Solution
A memory integrated circuit design featuring multiple word line drivers with p-type and n-type transistors, where the p-type transistor turns on with a nonpositive gate voltage, and control circuitry applies specific bias arrangements to manage word line selection and deselection, including the use of depletion mode transistors and standby pumps to optimize power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional 2T word line driver designs are used, then word line selection functionality is achieved, but power consumption increases and leakage current occurs
Solution Approach 1:
The patent changes the voltage parameter characteristics by using a p-type transistor that turns on with nonpositive gate voltage (0V or negative) instead of conventional positive voltage requirements. This parameter change enables the transistor to remain off during normal operation (reducing leakage) while turning on selectively when needed (reducing power consumption). The depletion mode p-type transistor specifically utilizes its natural off-state at zero bias to minimize leakage current.
2Device complexity
If conventional 2T word line driver designs are used, then word line driver functionality is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates unnecessary bias circuitry from conventional designs. By using a p-type transistor that naturally turns on at nonpositive voltages, the design removes the need for complex positive bias generation circuits, simplifying the overall device while maintaining reliable power management. The bias arrangements are simplified to only require negative voltage generation for selective activation.
3Area of stationary object
If die size decreases, then integration density improves, but power requirements become more stringent
Solution Approach 1:
The p-type transistor serves itself by utilizing nonpositive gate voltages (0V or negative) to control its on/off states. During deselection, the transistor naturally remains off without requiring active biasing, and during selection, it turns on when the appropriate negative voltage is applied. This self-service characteristic reduces the need for additional power management circuitry, enabling compact die designs with stringent power requirements to be met efficiently.
Data Source
AI summary
A two transistor word line driver is disclosed. An example disclosed word line driver is simplified with common signals on the gates of the p-type and the n-type transistors. An example disclosed word line driver consumes less power by applying a negative voltage to a word line driver selected from multiple word line drivers.