Programmable Clock Ramp-Up to Limit Ungating Voltage Droop
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Solution Overview
Problem
High-speed digital electronics experience voltage droop due to fast clock signal frequency changes, leading to power inefficiency and performance degradation, especially when clock signals are ungated in digital circuitry.
Innovation Solution
Implementing a voltage droop mitigation circuit that modulates clock frequency using programmable mask patterns or Boolean functions, allowing for a gradual ramp-up from zero to full nominal frequency, reducing the impact of clock ungating and minimizing voltage droop through controlled clock enablement and disablement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If clock frequency is rapidly changed during ungating, then power consumption is reduced, but voltage droop increases
Solution Approach 1:
The patent applies dynamics by making the clock frequency change adaptive rather than fixed. The frequency ramp rate is dynamically adjusted based on detected voltage droop levels - when droop is detected, the ramp rate is reduced to allow voltage to stabilize, and when no droop is present, the ramp rate can be increased to improve power efficiency. This dynamic adaptation resolves the contradiction between power savings from rapid frequency changes and voltage stability.
Solution Approach 2:
The patent implements feedback by continuously monitoring voltage droop during clock ungating operations and using this information to adjust the frequency ramp rate. The voltage droop detection circuit provides real-time feedback about the electrical state, which controls the modulator to adjust the clock frequency transition characteristics. This closed-loop feedback mechanism enables the system to achieve power efficiency while preventing excessive voltage droop.
2Productivity
If clock frequency ramps up quickly from zero to nominal frequency, then productivity is improved, but voltage droop and power inefficiency increase
Solution Approach 1:
The system dynamically adjusts the clock frequency ramp rate based on real-time voltage droop detection. Instead of using a fixed rapid ramp-up, the frequency transition is made adaptive - the ramp rate is modulated according to the actual electrical conditions. This allows the system to achieve fast restoration when conditions permit while preventing power inefficiency and voltage droop when conditions require more gradual transitions.
Solution Approach 2:
The patent changes the parameter of frequency ramp rate from a static value to a dynamically adjustable parameter. By modifying the ramp rate parameter based on voltage droop detection, the system can optimize between productivity (faster ramping) and power efficiency (slower ramping to avoid droop). The modulator adjusts the frequency transition characteristics in real-time, enabling parameter optimization for different operating conditions.
3Use of energy by moving object
If clock ungating is used to reduce power consumption, then energy efficiency is improved, but voltage droop and performance degradation occur
Solution Approach 1:
The patent uses feedback to maintain reliability during power-saving operations. The voltage droop detection circuit continuously monitors the electrical state during clock ungating and provides feedback to the frequency modulator. When voltage droop threatens to degrade performance, the feedback triggers an adjustment in the frequency ramp rate to allow voltage to stabilize, thus preventing performance degradation while maintaining the power consumption benefits of clock ungating.
Solution Approach 2:
The system dynamically adapts the clock frequency restoration behavior based on real-time voltage conditions. Instead of using a fixed aggressive ramp-up that causes droop, the system makes the frequency transition dynamic - adjusting the ramp rate according to detected voltage levels. This dynamic behavior enables the circuit to achieve both power efficiency and performance reliability by adapting to actual operating conditions.
Data Source
AI summary
Aspects of the disclosure are directed to reducing clock-ungating induced voltage droop by determining a maximum frequency value associated with an output clock waveform; modulating a clock frequency of the output clock waveform for a first time duration based on a first programmable mask pattern or a first Boolean function; and determining if either the first programmable mask pattern or the first Boolean function should be changed. In accordance with one aspect, a voltage droop mitigation circuit includes a control logic for receiving an input clock waveform and a clock enable signal waveform and for outputting a gated clock enable signal waveform; a latch coupled to the control logic, the latch for holding a state of the gated clock enable signal waveform and a AND gate coupled to the latch, the AND gate for outputting an output clock waveform.