Power-Gating Transistor Circuit With Capacitive Gate Hold
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Solution Overview
Problem
In semiconductor devices using power gating, high on-state resistance in switching transistors leads to voltage drops, preventing adequate voltage supply to logic circuits, while high off-state resistance increases standby current, necessitating a balance between resistance states to minimize power consumption and ensure reliable operation.
Innovation Solution
A programming element comprising a first transistor, a second transistor, and a capacitor is used, where the drain electrode of the first transistor, the gate electrode of the second transistor, and one electrode of the capacitor are electrically connected, allowing for controlled power supply to the logic circuit through the second transistor, with capacitive coupling to maintain node potential and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the on-state resistance of the switching transistor is reduced to ensure adequate voltage supply to the logic circuit, then the voltage drop is suppressed, but the off-state resistance decreases leading to increased standby current and power consumption
Solution Approach 1:
The power gating function is divided into two separate transistors: a first switching transistor for controlling power supply to the logic circuit, and a second switching transistor for controlling the gate electrode potential. This segmentation allows independent optimization of on-state resistance (first transistor) and off-state resistance (second transistor) without compromising the other parameter.
Solution Approach 2:
A capacitor is introduced as an intermediary element connected to the gate electrode of the second transistor. The capacitor maintains the gate electrode potential when the first transistor is turned off, enabling the second transistor to sustain low resistance state without requiring continuous high potential supply, thus reducing standby current while maintaining voltage supply adequacy.
2Reliability
If a high potential is supplied to the gate electrode of the switching transistor to reduce on-state resistance, then voltage drop is suppressed, but the potential change becomes large increasing power consumption
Solution Approach 1:
The capacitor is pre-charged to the required potential level before the first transistor is turned off. This preliminary action stores the necessary energy in the capacitor, allowing the gate electrode potential to be maintained without requiring large potential changes during operation, thus reducing power consumption while ensuring voltage supply stability.
Solution Approach 2:
The capacitor acts as an intermediary energy storage element that decouples the gate electrode potential control from the main power supply. By using the capacitor to maintain the potential, large potential swings are avoided, reducing the energy required for potential changes while maintaining stable voltage supply to the logic circuit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses voltage drops to the gate electrode, reduces power consumption, and enhances the reliability and yield of semiconductor devices by maintaining low on-state and high off-state resistances, thereby optimizing power management.
Implementation Method 1
resuming supply of the power supply potential to the logic circuit from the power source by making a potential of the node in the floating state a potential capable of turning on the second transistor using capacitive coupling between the node and the other of the electrodes of the capacitor
Data Source
AI summary
A programming element including a first transistor, a second transistor, and a capacitor between a logic circuit using a semiconductor element and a power supply is provided. In the programming element, a node where a drain electrode of the first transistor, a gate electrode of the second transistor, and one of electrodes of the capacitor are electrically connected to each other is formed. A potential can be supplied to each of a source electrode of the first transistor and the other of the electrodes of the capacitor. The power supply and the logic circuit are electrically connected to each other through a source electrode and a drain electrode of the second transistor. A connection state between the power supply and the logic circuit is controlled in accordance with the state of the second transistor.