Semiconductor Integrated Circuit Power Supply Switch Cell Layout
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Solution Overview
Problem
The existing power gating techniques in semiconductor integrated circuit devices require multiple switches, leading to increased area occupation and reduced layout flexibility, and result in significant power supply voltage drops due to long distances between switches, causing circuit malfunctions.
Innovation Solution
A semiconductor integrated circuit device configuration with a reduced number of switches, where switch cells are strategically placed every M sets of power supply lines, with adjacent switch cells arranged at different positions in the power supply straps, and connected via sub-power supply straps to minimize voltage drops, while maintaining effective power control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple switches are arranged in the circuit block to supply power to each standard cell power supply line, then power supply control is achieved, but the switches occupy a large area and reduce layout flexibility
Solution Approach 1:
Multiple switch cells are merged into a single shared switch cell that can control power supply to multiple standard cell power supply lines. The shared switch cell receives control signals and distributes power control to N power supply lines, eliminating the need for separate switches for each line and reducing the total area occupied by switches in the circuit block.
Solution Approach 2:
The shared switch cell is designed to perform multiple functions by controlling power supply to multiple different power supply lines. A single switch cell can be controlled to supply or shut off power to any of the N power supply lines it serves, making it a universal power control unit that replaces multiple specialized switches.
2Area of stationary object
If the number of switches is reduced to minimize area, then area is saved, but the distance between switches becomes long causing voltage drop
Solution Approach 1:
The power supply network is extended into the vertical dimension by introducing power supply straps in upper wiring layers. The shared switch cell connects to multiple power supply lines through these vertical straps, allowing power distribution in three-dimensional space rather than only in the planar layout. This reduces the effective distance for power delivery while maintaining area efficiency.
3Device complexity
If switches are placed far apart to reduce their number, then fewer switches are needed, but voltage drop occurs in the power supply lines between switches
Solution Approach 1:
Power supply straps are introduced as intermediary conductors between the shared switch cell and the multiple power supply lines. These straps act as intermediate power distribution channels that reduce the resistance and voltage drop in the power delivery path, enabling fewer switches to effectively serve more lines without compromising voltage stability.
Data Source
AI summary
A circuit block including standard cells (1) arranged therein is provided with switch cells (20) capable of switching between electrical connection and disconnection between power supply lines (3) extending in an X-direction and power supply straps (11) extending in a Y-direction. Each of the power supply straps (11) is provided with a single switch cell (20) arranged every M sets of power supply lines (3) (M is an integer of 3 or more). In the Y-direction, the switch cells (20) are arranged at different positions in the power supply straps (11) adjacent to each other, and are arranged at the same position every M power supply straps (11) in the X-direction.