Transistor Circuit Reducing Shutoff-State Current via Negative Feedback
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Solution Overview
Problem
As integrated circuit dimensions decrease, the threshold voltage of transistors also decreases, leading to increased shut-off-state current, which conflicts with the requirement for low-power integrated circuits that need minimal shut-off-state current to maintain long standby times.
Innovation Solution
A transistor circuit design that includes a first transistor connected in series with a transistor string and a switch, utilizing negative feedback and body effect voltage differences to reduce shut-off-state current, where the gate electrode of the first transistor is connected to the gate electrode of the transistor string, and the source and body regions are connected to a common terminal, with the switch controlling the circuit to minimize current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the channel length of the transistor is increased to reduce shutoff-state current, then the shutoff-state current decreases, but the transistor size and integrated circuit cost increase
Solution Approach 1:
The invention divides the single transistor channel into two separate paths: a main current channel and a feedback channel. The feedback channel includes a second transistor connected between the gate and source of the first transistor, creating a parallel path that enables negative feedback control. This segmentation allows the main channel to maintain a short length for small size while the feedback mechanism controls the shutoff-state current, resolving the contradiction between current reduction and size increase.
Solution Approach 2:
The invention implements negative feedback by connecting a second transistor in parallel with the gate-source path of the first transistor. When the first transistor is in shutoff state, the second transistor provides a feedback current that adjusts the gate-source voltage, thereby controlling and reducing the shutoff-state current without requiring an increase in channel length. This feedback mechanism directly addresses the contradiction by providing current control through electrical regulation rather than geometric scaling.
2Productivity
If the characteristic dimension of integrated circuits decreases to increase integration level, then the level of integration increases, but the shutoff-state current of transistors increases
Solution Approach 1:
The invention segments the transistor structure into a main switching transistor and a feedback control transistor, allowing the main transistor to maintain small dimensions for high integration while the feedback mechanism compensates for the increased shutoff-state current inherent in scaled devices. This enables continued scaling without proportionally increasing leakage current.
Solution Approach 2:
The invention changes the electrical parameters of the transistor system by introducing a feedback current that dynamically adjusts the gate-source voltage. This parameter change compensates for the threshold voltage reduction that occurs with scaling, thereby maintaining low shutoff-state current despite decreased characteristic dimensions and increased integration level.
3Loss of energy
If the channel length of the transistor is increased to reduce shutoff-state current, then the drift length of charge carriers increases, but the overall size of the integrated circuit increases
Solution Approach 1:
The invention segments the current control function from the main channel structure by adding a parallel feedback path with a second transistor. This allows the main channel to maintain its original length for compact design while the feedback path provides the necessary current control, eliminating the need to increase channel length.
Solution Approach 2:
The second transistor acts as an intermediary element that mediates between the gate-source voltage and the channel current. By introducing this intermediate control element, the invention achieves current reduction without modifying the physical dimensions of the main channel, thus resolving the contradiction between current control and length constraints.
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 design effectively reduces the shut-off-state current flowing through both the first transistor and the transistor string, maintaining low power consumption while preventing increased transistor size and cost.
Implementation Method 1
the body effect of the transistor to reduce the shut-off state current flowing through itself
Implementation Method 2
using the negative feedback function of the transistor string to reduce the shut-off state current when the circuit is in shut-off state
Data Source
AI summary
A transistor circuit of low shutoff-state current includes: a first transistor, a transistor string, and a switch. The first transistor and the transistor string are connected in series. The switch is configured to shut off the circuit. The first transistor is configured to reduce the shutoff-state current flowing therethrough using the negative feedback effect of the transistor string when the circuit is in a shutoff state; and the transistor string is configured to reduce the shutoff-state current flowing therethrough using a negative gate-source electrode voltage difference thereof and the bulk effect of the transistor.