Voltage Generator Dynamic Transistor Control Standby Current
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Solution Overview
Problem
Semiconductor memory devices face issues with high stand-by current and long response times due to unstable internal voltages and decreased drivability, particularly in low-power and mobile products, where the conventional voltage generators fail to effectively manage the precharge mode and active mode operations.
Innovation Solution
A voltage generator with an active control unit that selectively drives transistors in the output driver, using active controllers and selecting drivers to adjust the drivability based on bank active signals, reducing stand-by current and improving response times by optimizing the operation of pull-up and pull-down driving signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the core voltage level is decreased to enable higher integration, then the integration density is improved, but the drivability for VBLP and VCP deteriorates
Solution Approach 1:
The patent changes the voltage parameters by generating boosted voltages (VBST_P and VBST_N) that are higher than the core voltage VCORE. This allows the output driver to compensate for the lower core voltage level and maintain sufficient drivability for VBLP and VCP even when VCORE is reduced for higher integration density.
Solution Approach 2:
The patent introduces an intermediate voltage boosting stage between the core voltage generator and the output driver. The bias voltage generator creates intermediate voltages (VBST_P and VBST_N) that serve as mediators to enhance the driving capability without requiring a higher core voltage level.
2Speed
If the output driver transistors are always on to maintain drivability, then the response time is improved, but the standby current increases
Solution Approach 1:
The patent makes the output driver transistors dynamic by selectively turning them on and off based on operational mode. During active mode, the transistors are turned on to provide fast response; during standby mode, they are turned off to minimize leakage current. This dynamic control resolves the contradiction between response time and standby power consumption.
Solution Approach 2:
The patent implements periodic activation of the output driver transistors based on mode signals. The transistors are activated only when needed (during active mode) and deactivated during standby mode, creating a periodic on-off pattern that reduces energy loss while maintaining readiness when required.
3Object-generated harmful factors
If the threshold voltage of output driver transistors is reduced to prevent voltage drop, then the drivability is improved, but the standby current increases
Solution Approach 1:
Instead of changing the transistor threshold voltage parameter, the patent changes the supply voltage parameters by providing boosted voltages (VBST_P and VBST_N) to the output driver. This allows the use of standard threshold voltage transistors while still preventing voltage drop and maintaining drivability.
Solution Approach 2:
The patent introduces boosted voltage intermediaries (VBST_P and VBST_N) that mediate between the core voltage and the output driver transistor gates. These intermediate voltages provide the necessary driving strength without requiring low-threshold-voltage transistors, thereby avoiding increased standby leakage current.
Data Source
AI summary
A voltage generator reduces a stand by current in a stand by or a self-refresh mode and shortens a response time in an active mode by selectively driving a control transistor of a final driver. A core voltage control unit provides a power voltage. Pull-up and pull-down driving signals are generated based on the power voltage. An output driver generates an internal voltage according to the pull-up and pull-down driving signals. An active control unit controls drivability of the core voltage control unit in response to bank active signals.