Clock Gating Circuit Layout for Lower Dynamic Clock Power
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Solution Overview
Problem
In semiconductor integrated circuits, clock trees face issues with timing errors due to differences in clock signal arrival times and increased power consumption, which affect performance and area efficiency as circuits become smaller and more complex.
Innovation Solution
A clock gating circuit is implemented, comprising a NOR logic gate, a transmission gate, a cross-coupled pair of transistors, and a first transistor, which reduces the number of transistors toggled by the inverted clock signal, resulting in lower dynamic clock power consumption and reduced area occupancy compared to other clock gating cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional clock gating circuits are used, then clock signal distribution is achieved, but dynamic clock power consumption increases due to multiple transistors being toggled
Solution Approach 1:
The patent extracts and eliminates unnecessary transistors from the clock gating circuit. By removing redundant switching elements that are not essential for clock gating functionality, the circuit toggles fewer transistors with the clock signal, directly reducing dynamic power consumption while preserving the essential clock distribution and gating functions.
Solution Approach 2:
The patent merges multiple transistor functions into a more efficient configuration. By combining the clock gating function with enable signal control in a streamlined transistor arrangement, the circuit achieves the same clock distribution function with fewer active components, thereby reducing dynamic power consumption without compromising timing reliability.
2Area of stationary object
If conventional clock gating circuits are used, then clock signal distribution is achieved, but area occupancy increases
Solution Approach 1:
The patent removes unnecessary transistors and circuit elements from the clock gating structure. By extracting redundant components that do not contribute to essential clock gating functionality, the physical area occupied by the circuit is reduced while maintaining reliable clock signal distribution and timing control.
Solution Approach 2:
The patent combines multiple functions into a compact transistor configuration. By merging clock gating, enable signal response, and clock signal transmission into a streamlined circuit topology, the area occupancy is minimized while preserving timing reliability and preventing clock signal arrival errors.
3Reliability
If more transistors are used in clock gating circuit, then clock signal control is improved, but power consumption and area increase
Solution Approach 1:
The patent identifies and removes excess transistors that do not contribute to essential clock signal control. By extracting redundant switching elements, the circuit maintains adequate clock gating functionality with fewer components, thereby reducing power consumption while preserving necessary control capabilities.
Solution Approach 2:
The patent optimizes the transistor configuration parameters to achieve efficient clock signal control. By adjusting the number and arrangement of transistors to minimal necessary levels, the circuit achieves reliable clock gating with reduced power consumption, avoiding both over-provisioning and under-provisioning of control elements.
Data Source
AI summary
A clock gating circuit includes a NOR logic gate, a transmission gate, a cross-coupled pair of transistors, and a first transistor. The NOR logic gate is coupled to a first node, and receives a first and a second enable signal, and outputs a first control signal. The transmission gate is coupled between the first and a second node, and receives the first control signal, an inverted clock input signal and a clock output signal. The cross-coupled pair of transistors is coupled between the second node and an output node, and receives at least a second control signal. The first transistor includes a first gate terminal configured to receive the inverted clock input signal, a first drain terminal coupled to the output node, and a first source terminal coupled to a reference voltage supply. The first transistor adjusts the clock output signal responsive to the inverted clock input signal.