Negative Voltage Generation Circuit for DRAM Standby Current Reduction
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Solution Overview
Problem
Dynamic Random Access Memory (DRAM) using P channel MOS transistors faces challenges with high-speed response, increased current consumption, circuit failure due to excessive stress, and noise sensitivity, especially in battery-driven portable equipment with reduced power supply voltage and increased ground voltage.
Innovation Solution
A semiconductor device with multiple negative voltage supply lines, detection circuits, and charge supply circuits, along with a control circuit to manage activation in active and standby modes, and a reference voltage generation circuit with a stabilization capacitor to maintain voltage stability and reduce noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the through current flowing to the negative voltage detection circuit is increased to allow higher speed in response, then the response speed of the negative voltage generation circuit is improved, but the standby current consumption is increased
Solution Approach 1:
The patent applies dynamics by making the negative voltage generation circuits configurable between active and inactive states through control circuits. During active mode, circuits operate at full speed with higher current; during standby mode, circuits are deactivated to reduce current consumption. This dynamic state transition resolves the contradiction between response speed and standby current consumption.
Solution Approach 2:
The patent implements periodic action by alternately activating and deactivating negative voltage generation circuits based on operational mode. The control circuit switches between active mode (requiring fast response) and standby mode (requiring low current consumption), allowing the system to achieve high-speed response when needed while minimizing power consumption during idle periods.
2Device complexity
If a single negative voltage generation circuit is used for multiple memory circuits, then the device complexity is reduced, but the variation in negative voltage increases
Solution Approach 1:
The patent applies segmentation by dividing the single negative voltage generation circuit into multiple independent circuits, each dedicated to serving one or more specific memory circuits. This segmentation ensures that each memory circuit receives a stable negative voltage without interference from others, reducing voltage variation while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The patent implements universality by designing multiple negative voltage generation circuits that can be selectively activated based on operational requirements. The control circuit determines which circuits to activate, allowing the system to use more circuits (reducing variation) when needed and fewer circuits (reducing complexity) when not needed, providing flexible multi-functionality.
3Use of energy by moving object
If the power supply voltage is reduced and ground voltage is increased to lower power consumption, then the power consumption is reduced, but the operation speed is reduced
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the negative voltage level based on operational mode. During active mode, the negative voltage is maintained at a level that ensures high operation speed. During standby mode, the negative voltage can be relaxed to reduce power consumption. This parameter adjustment allows the system to optimize between speed and power consumption based on real-time requirements.
4Stability of the object's composition
If a negative voltage generation circuit is always active to maintain negative voltage, then the negative voltage stability is improved, but the standby current consumption is increased
Solution Approach 1:
The patent applies dynamics by implementing control circuits that dynamically switch negative voltage generation circuits between active and inactive states. During active mode, circuits remain active to maintain stable negative voltage. During standby mode, circuits are deactivated to reduce current consumption. This dynamic control resolves the contradiction between voltage stability and standby current consumption.
Solution Approach 2:
The patent implements self-service by designing the control circuit to automatically manage the activation and deactivation of negative voltage generation circuits based on operational mode detection. The system self-regulates power consumption without external intervention, maintaining voltage stability when needed and reducing consumption during standby, eliminating the need for manual configuration.
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
The solution enables high-speed operation with low standby current, prevents excessive stress during burn-in tests, and enhances noise immunity while maintaining operation speed and reducing voltage variations.
Implementation Method 1
a stabilization capacitor having one electrode connected to the reference voltage line and the other electrode receiving the power supply voltage from the power supply voltage line
Data Source
AI summary
A semiconductor integrated circuit device has a negative voltage generation circuit provided at each power supply circuit unit for six memory macros. Therefore, the response with respect to variation in a negative voltage is increased. In a standby mode, a negative voltage supply line for the six memory macros is connected by a switch circuit, and only a negative voltage generation circuit of one power supply circuit unit among six negative voltage generation circuits of the six power supply circuit units is rendered active. Thus, increase in standby current can be prevented.