Cascoded Electronic Switch Biasing for GIDL Leakage Control
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Solution Overview
Problem
Electronic switches face challenges in minimizing leakage current due to Gate Induced Drain Leakage (GIDL) when in the off state, particularly as voltage levels fluctuate between VSS and VDD, affecting signal integrity and circuitry stability.
Innovation Solution
The electronic switch employs cascoded transistors with one gate biased at an intermediate voltage and injection shunting devices to prevent voltage fluctuations, minimizing GIDL leakage by ensuring the drain-to-gate voltage remains below or above the GIDL threshold, depending on the transistor type, and using injection shunting devices to maintain node voltages within safe limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional switch transistors are used without intermediate voltage biasing, then the device complexity is low, but leakage current due to GIDL increases significantly
Solution Approach 1:
The patent introduces intermediate voltage biasing circuits as mediators between the control signal and the transistor gates. These intermediary circuits generate the required intermediate voltage levels (e.g., VDD/2, VSS+Vth) to bias the cascoded transistor gates, thereby reducing GIDL leakage current without requiring complete redesign of the switch architecture.
Solution Approach 2:
The patent changes the voltage parameter applied to the transistor gates from binary (0 or VDD) to multi-level (including intermediate voltages like VDD/2, VSS+Vth). By adjusting the gate voltage to intermediate levels, the drain-to-gate voltage difference is reduced, which directly suppresses GIDL leakage current while maintaining the switch's fundamental operation.
2Object-generated harmful factors
If cascoded transistors with intermediate voltage biasing are used, then GIDL leakage current is reduced, but the device complexity increases
Solution Approach 1:
The patent segments the single transistor into a cascoded structure with multiple transistors connected in series. This segmentation allows independent control of each transistor's gate voltage, enabling the application of intermediate voltage biasing to specific transistors to suppress GIDL leakage current in critical regions while keeping other regions simpler.
Solution Approach 2:
The patent applies intermediate voltage biasing selectively to specific transistors within the cascoded structure, particularly to those experiencing high drain-to-gate voltage differences. This local quality approach ensures that GIDL suppression is applied where most needed, rather than uniformly across all transistors, optimizing the trade-off between leakage reduction and complexity.
3Stability of the object's composition
If injection shunting devices are added to maintain node voltages, then signal path stability is improved, but the device complexity increases
Solution Approach 1:
The patent introduces injection shunting devices as intermediary components connected to critical nodes in the signal path. These devices act as voltage regulators that shunt excess charge or inject compensating charge to maintain node voltages within safe limits, preventing voltage excursions that could cause leakage or distortion.
Solution Approach 2:
The injection shunting devices are configured to preemptively counteract voltage fluctuations before they can cause harmful effects. By continuously monitoring and adjusting node voltages, these devices prevent voltage from reaching levels that would trigger GIDL or affect signal integrity, rather than reacting after problems occur.
Data Source
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AI summary
An electronic switch that includes a signal path with a first terminal side of the signal path including cascoded transistors in the signal path. When the switch is in an off state, the gate of one of the cascoded transistors is biased at an intermediate voltage different from the voltage applied to the gate of the other of the cascoded transistors. In one embodiment, having the gate of one of the cascoded transistors biased at an intermediate voltage in an off state may reduce leakage current into a signal terminal of the switch. The electronic switch includes an injection shunting device (e.g. such as a transistor) connected to a node of the signal path. In one embodiment, the injection shunting device prevents the voltage of the node from reaching a specific voltage level due to leakage current when the switch is in an off state.