Word Line Driver Boosted Voltage Generation Current Consumption
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Solution Overview
Problem
Conventional semiconductor memory devices face inefficiencies in the boosted voltage generation process, leading to excessive current consumption due to limited efficiency in the charge pumping process, which results in unnecessary power wastage when generating the boosted voltage VPP from the internal power supply voltage VINT.
Innovation Solution
A semiconductor memory device with a word line driver that includes a boosted voltage generator, a sub word line driver, and a main word line driver, where the internal power supply voltage and boosted voltage are sequentially supplied to optimize the boosted voltage generation, reducing unnecessary current consumption by primarily using the internal power supply voltage and secondarily boosting it to the boosted voltage level only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boosted voltage VPP is generated by pumping electric charge from the internal power supply voltage VINT in conventional semiconductor memory devices, then the word line can be enabled to recover data in memory cells, but a predetermined amount of current is consumed due to limited efficiency of the boosted voltage generator
Solution Approach 1:
The patent applies preliminary action by pre-charging the word line to the internal power supply voltage VINT before enabling it with the boosted voltage VPP. This two-stage voltage application ensures that the word line is already at a partial voltage level, reducing the charge pumping requirement and thereby decreasing current consumption while maintaining reliable data recovery capability.
2Reliability
If the boosted voltage VPP is used to compensate for threshold voltage drop in the word line driver, then the word line can be properly enabled, but additional current component is consumed due to the charge pumping process
Solution Approach 1:
The patent segments the voltage boosting process into two distinct stages: first applying the internal power supply voltage VINT to pre-charge the word line, then applying the boosted voltage VPP to compensate for threshold voltage drop. This segmentation allows each voltage to perform its specific function efficiently, reducing the overall energy loss in the charge pumping process while maintaining reliable threshold voltage compensation.
3Reliability
If the word line is enabled with boosted voltage VPP in self-refresh operation, then data recovery is achieved, but unnecessary current consumption occurs since the boosted voltage generator operates continuously
Solution Approach 1:
The patent implements periodic action by controlling the boosted voltage generator to operate only when needed for word line enabling during self-refresh operations. The internal power supply voltage VINT is used for pre-charging, and the boosted voltage VPP is applied periodically only when data recovery is required, rather than continuously operating the charge pumping circuit, thereby improving power efficiency while maintaining reliable self-refresh functionality.
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 approach enhances the efficiency of boosted voltage supply in semiconductor memory devices by reducing the total internal power supply current consumption by 10 mA, achieving a higher efficiency of 100% for the primary current and minimizing additional current usage during self-refresh operations.
Implementation Method 1
a boosted voltage generator (10) for generating a boosted voltage VPP by receiving an internal power supply voltage VINT and pumping electric charge
Data Source
AI summary
A word line driver for use in a semiconductor memory device includes a boosted voltage generator, a sub word line driver and a main word line driver. The boosted voltage generator generates a boosted voltage by receiving an internal power supply voltage and pumping electric charge. The sub word line driver receives the internal power supply voltage and activates a boosted voltage control signal after supplying the internal power supply voltage to a boost node in a command operating mode. The main word line driver enables a word line by supplying the boosted voltage to the boost node in response to the boosted voltage control signal in a normal operating mode, and enables the word line with the boosted voltage after boosting the word line to the internal power supply voltage by changing the boost node from the internal power supply voltage to the boosted voltage in the command operating mode.