Tiered Virtual Ground Regulation for SoC Leakage and Data Retention
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Solution Overview
Problem
Static leakage power consumption is a significant challenge in very large scale system-on-a-chip (SoC) integrated circuits, particularly in handheld devices, as it increases with finer geometry manufacturing processes, making it difficult to meet chip leakage targets using traditional power reduction techniques.
Innovation Solution
A data processor with multiple low power modes is implemented, utilizing virtual ground terminals and tiered voltage regulators to selectively adjust power supply voltages, ensuring data retention while minimizing leakage current by enabling or disabling voltage regulators based on operating modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If voltage regulators are used to reduce leakage current by elevating virtual ground potential, then static leakage power consumption is reduced, but data retention voltage requirements may be violated causing data corruption
Solution Approach 1:
The voltage regulator system is segmented into a global voltage regulator for overall leakage reduction and multiple local voltage regulators for specific circuit blocks. This segmentation allows selective application of leakage reduction techniques to different parts of the system, enabling leakage current reduction while maintaining data retention voltage requirements for critical blocks like cache memories through independent control of each segment's virtual ground elevation.
Solution Approach 2:
The system dynamically adjusts the virtual ground potential elevation based on operational requirements. The global and local voltage regulators are controlled to provide different levels of virtual ground elevation depending on whether data retention is required, allowing the system to transition between leakage reduction modes and data retention modes as needed.
2Productivity
If finer geometry manufacturing processes are used to increase transistor density, then processing capacity is improved, but transistor leakage currents increase
Solution Approach 1:
The invention changes the electrical parameters of the system by elevating the virtual ground potential above actual ground potential. This parameter change affects the voltage differential across transistors, thereby reducing leakage currents. The global voltage regulator implements this parameter change system-wide, while local voltage regulators can apply it selectively to specific circuit blocks experiencing high leakage.
Data Source
AI summary
A processor includes a first virtual terminal, a second virtual terminal, circuitry coupled to the first virtual terminal for providing current to the first virtual terminal, a first regulating transistor coupled between the first virtual terminal and the second virtual terminal, a first disabling transistor coupled in parallel with the first regulating transistor for selectively disabling the first regulating transistor by directly connecting the second virtual terminal to the first virtual terminal, a second regulating transistor coupled between the second virtual terminal and a first power supply voltage terminal, and a second disabling transistor coupled in parallel with the second regulating transistor for selectively disabling the second regulating transistor by directly connecting the second virtual terminal to the first power supply voltage terminal.