Power Gate Voltage Boosting for Leakage Reduction
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Solution Overview
Problem
Power gating in electronic devices faces challenges in achieving an infinite I-on and zero I-off current ratio, leading to inefficiencies in power consumption due to IR drops and leakage currents, especially at near-threshold or sub-threshold voltages, making it difficult to balance performance and energy efficiency.
Innovation Solution
The solution involves an electronic device with circuitry operating in a first voltage domain and a power gate controlled by a gating signal generated in a second voltage domain with a higher voltage level, allowing for boosted gate operation without the need for additional voltage generators, using existing higher voltage sources within the device, such as batteries or energy harvesters, to enhance the I-on to I-off current ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If power gates are used to reduce leakage power, then energy consumption is reduced, but IR drop causes performance degradation
Solution Approach 1:
The patent changes the voltage parameter of the control signal to resolve the contradiction. By providing the control signal at a higher voltage level than the circuitry operating voltage, the power gate achieves lower resistance when on, reducing IR drop and improving circuit performance while maintaining leakage reduction capability
2Power
If more power gates are used to supply worst case functional power, then power delivery is improved, but leakage current increases
Solution Approach 1:
The patent uses higher voltage control signals to improve the switching characteristics of power gates, enabling fewer power gates to achieve the required functional power delivery while maintaining low leakage. The boosted control voltage creates stronger electric fields for better channel control
3Use of energy by moving object
If operating voltage is reduced to save power, then energy efficiency is improved, but I-on to I-off ratio decreases
Solution Approach 1:
The patent decouples the control signal voltage from the circuitry operating voltage by providing the control signal at a higher voltage level. This allows the circuitry to operate at low voltage for energy efficiency while the power gate control remains at high voltage to maintain a strong I-on to I-off ratio
4Reliability
If additional voltage generators are used to boost gate voltage, then I-on to I-off ratio is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing higher voltage source serve multiple functions: it continues to power the control circuitry and simultaneously provides the boosted control signal for power gates. This eliminates the need for separate voltage generators specifically for power gate control
Solution Approach 2:
The system uses its own existing higher voltage source to provide the boosted control signal, making the system self-sufficient without requiring external or additional dedicated voltage generation circuitry for power gate control
Data Source
AI summary
An electronic device 2 has circuitry 4 which operates in a first voltage domain 6 supplied with a first voltage level VDD1 and a reference voltage level. A voltage regulator 14 generates the first voltage level VDD1 from a second voltage level VDD2 higher than the first voltage level VDD1. At least one power gate 20, 30 is provided for selectively coupling the circuitry 4 to one of the first voltage level VDD1 or the reference level. The control signal 22 for the power gate 20, 30 is generated in a second voltage domain supplied with a higher voltage level VDD2 or VDD3 derived from the second voltage level VDD2 supplied to the voltage regulator 14. Hence, an existing high voltage source within the device 2 can be reused for applying a boosted voltage to power gates to improve efficiency of power gating.