Semiconductor Memory Body Bias Control for Leakage and Power-Down Exit
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Solution Overview
Problem
Semiconductor memory devices face challenges in efficiently managing power consumption and stabilizing body bias voltages during different operational modes, particularly in mobile devices where rapid power-down exit and reduced leakage current are crucial.
Innovation Solution
A semiconductor memory device with a body bias control unit and a body bias generator that detects commands to generate body bias selection signals and down-converts power supply voltages to provide appropriate body voltages to transistors, allowing for quick stabilization and reduced power consumption by adjusting voltage levels based on operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If body bias voltage is increased to reduce leakage current during power-down mode, then power consumption is reduced, but the time required to stabilize body bias voltage upon exiting power-down mode increases
Solution Approach 1:
The body bias control unit segments the body bias voltage control into different levels based on operational modes. During power-down mode, a first level body bias voltage is applied to minimize leakage current, while during active mode, a second level body bias voltage is applied to enable fast operation. This segmentation allows the system to optimize for either low power or fast response depending on the operational state, resolving the contradiction between leakage reduction and quick power-down exit.
2Use of energy by stationary object
If body bias voltage is dynamically adjusted according to operational modes, then power consumption is optimized, but device complexity increases
Solution Approach 1:
The body bias control unit automatically detects the operational mode and selects the appropriate body bias voltage level without requiring external intervention or complex control algorithms. The system self-adjusts the body bias voltage based on internally generated mode detection signals, simplifying the overall control architecture while achieving dynamic power optimization. This self-service mechanism reduces the complexity burden that would otherwise arise from manual or externally-controlled dynamic bias adjustment.
3Speed
If high power supply voltage is used to ensure fast operation, then operating speed is improved, but power consumption increases
Solution Approach 1:
The body bias voltage is dynamically adjusted based on the operational mode rather than maintaining a fixed high voltage level. During active mode, sufficient body bias voltage is applied to ensure fast transistor switching and high operating speed. During power-down mode, the body bias voltage is reduced to minimize leakage current. This dynamic adjustment allows the system to achieve high speed when needed while consuming minimal power during idle periods, resolving the contradiction between speed and power consumption.
Data Source
AI summary
A semiconductor memory device is provided which includes a function block including a plurality of transistors; a body bias control unit configured to detect a command and to generate a body bias selection signal according to the detection result; and a body bias generator configured to generate a body voltage according to the body bias selection signal and to provide the body voltage to bodies of the plurality of transistors, wherein the body bias generator down-converts a power supply voltage supplied from an external device to generate the body voltage.