SCRC Gate Charge Transfer to Cut Switching Supply Current
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Solution Overview
Problem
Sub-threshold current reduction circuit (SCRC) switches with oversized transistors consume excessive power and chip area due to large switching currents and leakage currents, which undermines the reduction of leakage current and increases power supply current, while also limiting the miniaturization of electronic devices.
Innovation Solution
Implementing a charge transfer circuit between the gate terminals of pull-up and pull-down SCRC transistors to reduce the power supply current by utilizing unused charge for switching, thereby minimizing the need for power from the supply lines and optimizing transistor sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oversized transistors are used for SCRC switches, then switching capability is improved, but power consumption and chip area increase excessively
Solution Approach 1:
The patent applies preliminary action by pre-charging the gate terminals of SCRC transistors before switching operations. The charge pump circuit accumulates charge in advance and transfers it to the gate terminals, so that when switching is needed, the transistors can switch rapidly without requiring excessive current from the power supply during the switching event itself.
Solution Approach 2:
The patent introduces a charge pump circuit as an intermediary between the power supply and the SCRC transistor gate terminals. This intermediary device stores and transfers charge efficiently, reducing the direct current demand on the power supply while maintaining the necessary switching capability of the transistors.
2Reliability
If oversized transistors are used for SCRC switches, then switching capability is improved, but chip area increases excessively
Solution Approach 1:
By pre-charging gate terminals using the charge pump circuit, the patent enables smaller transistors to achieve the same switching capability. The preliminary charge accumulation allows rapid switching without requiring oversized transistor dimensions, thus reducing chip area while maintaining switching performance.
3Speed
If large switching currents are used, then transistor switching is improved, but power supply current increases
Solution Approach 1:
The charge pump circuit performs preliminary charge accumulation and transfers it to gate terminals before switching is required. This eliminates the need for large instantaneous switching currents from the power supply, as the charge is already available at the gate terminals, maintaining fast switching speed while reducing power supply current demand.
Solution Approach 2:
The charge pump acts as an intermediary that decouples the power supply current from the switching current. It accumulates charge from the power supply at a lower current rate and delivers it rapidly to gate terminals when needed, achieving fast switching without proportionally high power supply current.
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 approach results in a 20% reduction in power supply current during SCRC transistor switching and more efficient use of chip area, addressing the issues of excessive power consumption and size limitations.
Implementation Method 1
Implementing a charge transfer circuit between the gate terminals of pull-up and pull-down SCRC transistors to reduce the power supply current by utilizing unused charge for switching
Data Source
AI summary
Charge transfer between gate terminals of sub-threshold current reduction circuit (SCRC) transistors and related apparatuses and methods is disclosed. An apparatus includes a pull-up SCRC transistor, a pull-down SCRC transistor, and a charge transfer circuit. The pull-up SCRC transistor includes a pull-up gate terminal. The pull-down SCRC transistor includes a pull-down gate terminal. The charge transfer circuit is electrically connected between the pull-up gate terminal and the pull-down gate terminal. The charge transfer circuit is configured to transfer charge between the pull-up gate terminal and the pull-down gate terminal.