Dual-Edge Clock Pulse Generation With Duty Cycle Balancing
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Solution Overview
Problem
As circuit density and clock rates increase in integrated circuits, the dynamic power consumption rises, with clocking circuitry being a significant contributor, necessitating enhanced power efficiency in pulse latch circuitry.
Innovation Solution
Implementing a dual-edge clocking scheme with phase-locked loops (PLLs) that generate square-wave clock signals, using adaptive duty cycle distortion correction circuitry to balance the duty cycle and adjust clock buffer drive strengths, and employing pulse generators that trigger clock pulses at both rising and falling edges to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional single-edge clocking schemes are used, then the circuit operation is simple, but the power consumption is high
Solution Approach 1:
The patent implements dual-edge clocking where pulse latches are triggered by both rising and falling edges of the clock signal. This periodic action on both edges allows the circuit to perform the same computational work in half the time, reducing the frequency requirement and thereby reducing dynamic power consumption by approximately 50% compared to single-edge clocking schemes.
Solution Approach 2:
The patent changes the clocking parameter from single-edge triggering to dual-edge triggering. This parameter change enables the pulse latches to utilize both rising and falling edges of the clock signal, effectively doubling the utilization of the clock resource and reducing the required clock frequency for the same performance, which directly reduces power consumption.
2Use of energy by moving object
If dual-edge clocking is implemented, then power consumption is reduced, but duty cycle distortion occurs
Solution Approach 1:
The patent incorporates feedback mechanisms through delay-locked loops (DLLs) that continuously monitor the duty cycle of the clock signal and dynamically adjust the clock buffer drive strengths. This feedback ensures that despite process variations and loading effects, the duty cycle remains close to 50%, maintaining precision while enabling dual-edge clocking for power reduction.
Solution Approach 2:
The patent employs dynamic adjustment of clock buffer drive strengths based on real-time duty cycle measurements. The clocking system transitions from static to dynamic operation, where the buffer strengths are continuously optimized to maintain 50% duty cycle, enabling the system to adapt to varying conditions while preserving power efficiency.
3Manufacturing precision
If adaptive duty cycle distortion correction is used, then duty cycle accuracy is improved, but circuit complexity increases
Solution Approach 1:
The patent introduces delay-locked loops (DLLs) as intermediary circuits that mediate between the clock signal source and the pulse latches. These DLLs serve as intermediate stages that clean up the clock signal, correct duty cycle distortion, and provide phase-matched clock edges to the pulse latches, thereby improving duty cycle accuracy without requiring complex direct correction at the latch level.
Solution Approach 2:
The patent uses symmetric logic gates and transmission gates that are designed to match and copy the delay characteristics of each other. This copying of delay profiles ensures that the rising and falling edges experience matched delays, naturally balancing the duty cycle and reducing distortion without requiring extensive correction circuitry.
4Productivity
If pulse widths are balanced for both edges, then performance is optimized, but design complexity increases
Solution Approach 1:
The patent employs asymmetric design strategies where different logic implementations are used for rising-edge and falling-edge pulse generation. By carefully selecting complementary logic gates and transmission gates with matched but opposite characteristics, the design achieves balanced pulse widths through controlled asymmetry in the implementation, optimizing performance while managing complexity.
Solution Approach 2:
The patent applies local quality optimization by designing symmetric logic gates and transmission gates specifically at critical points in the pulse generation path. These locally optimized components are designed with matched delay characteristics to ensure that only the critical pulse paths have balanced delays, achieving optimal performance where needed without unnecessarily complicating the entire circuit.
Data Source
AI summary
Integrated circuits that support dual-edge clocking are provided. Integrated circuits may include phase-locked loops that generate square-wave clock signals. The clock signals may be provided from off-chip equipment through input-output pins. The clock signals may be routed through a clock distribution network to provide local clock signals to pulse generators that generate clock pulses on rising and falling clock edges. The pulse generators may generate clock pulses that are triggered by the rising and falling clock edges with a common pulse width for optimum performance. Duty cycle distortion introduced by the clock network may be minimized for optimum performance. Adaptive duty cycle distortion circuitry may be used to control the pull-up/pull-down drive strengths of the clock buffer so that the high clock phase of the local clock signals is approximately a half clock cycle.