RF Switch FET Body Bias Paths for GIDL Discharge Control
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Solution Overview
Problem
In RF switch stacks, the undesired gate-induced drain/body leakage current (GIDL) causes de-biasing effects, leading to early transistor breakdown and increased complexity and power consumption in biasing circuits, necessitating methods to reduce its impact while maintaining power handling and linearity performance.
Innovation Solution
The implementation of a field effect transistor (FET) switch stack with diode element arrangements that generate multiple current discharge paths for GIDL current through the body resistor ladder during different time intervals, providing symmetry and reducing voltage distribution asymmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a more negative biasing voltage is applied to improve linearity performance, then linearity performance is improved, but biasing circuit complexity and area increase
Solution Approach 1:
The patent converts the harmful GIDL current into a beneficial element by providing dedicated discharge paths that guide this current away from disrupting the bias network. The GIDL current, instead of causing de-biasing effects, is now safely discharged through controlled paths, allowing the use of more negative bias voltages for improved linearity without the original penalties.
Solution Approach 2:
The patent introduces diode elements as intermediary components that mediate between the GIDL current source and the biasing circuit. These diodes act as controlled pathways that allow GIDL current to discharge without interfering with the bias voltage distribution, thereby decoupling the linearity improvement from circuit complexity increase.
2Measurement precision
If a more negative biasing voltage is applied to improve linearity performance, then linearity performance is improved, but DC current consumption increases
Solution Approach 1:
The harmful GIDL current is converted into a controlled discharge path that does not contribute to DC current consumption. By providing dedicated discharge paths, the patent ensures that GIDL current flows through controlled paths rather than disrupting the bias network and increasing overall DC consumption, enabling more negative bias voltages without the original energy penalty.
Solution Approach 2:
Diode elements serve as intermediaries that separate the GIDL current flow from the DC bias current paths. This mediation allows the biasing circuit to maintain more negative voltages for linearity improvement while preventing GIDL current from adding to the DC current consumption burden.
3Device complexity
If GIDL current is allowed to flow through the body resistor ladder, then the circuit remains simple, but de-biasing effects occur causing early transistor breakdown
Solution Approach 1:
The patent introduces diode elements as intermediary components between the GIDL current source and the body resistor ladder. These diodes provide controlled discharge paths that protect the bias network from de-biasing effects while maintaining circuit simplicity. The diodes act as guardians that allow GIDL current to flow without disrupting the voltage distribution across the transistor bodies.
Solution Approach 2:
The patent applies preliminary protective action by providing dedicated GIDL discharge paths before the de-biasing effects can cause harm. The diode elements are positioned and biased to prevent GIDL current from interfering with the bias network, thereby preemptively avoiding the conditions that lead to early transistor breakdown while keeping the circuit design simple.
4Ease of operation
If GIDL current is sunk by the biasing circuit, then the circuit can operate, but the bias generator becomes more complex and occupies larger area
Solution Approach 1:
The patent extracts the GIDL current discharge function from the biasing circuit by providing dedicated discharge paths through diode elements. This separation allows the bias generator to focus solely on voltage generation without the additional complexity and area requirements of handling GIDL current sinking, while the circuit remains fully operational.
Solution Approach 2:
Diode elements serve as intermediary components that handle the GIDL current discharge function separately from the biasing circuit. This mediation allows the bias generator to maintain its compact design while still enabling proper circuit operation, as the diodes manage the GIDL current without requiring the bias generator to be enlarged or complicated.
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 effectively mitigates the de-biasing effect, enhances linearity performance, and allows for a simpler, more compact biasing circuit without compromising power handling capabilities.
Implementation Method 1
a first diode element arrangement comprising: i) a diode element stack comprising two or more diode elements, the diode element stack coupled between the body resistor ladder and the first terminal
Data Source
AI summary
Methods and devices to reduce gate induced drain leakage current in RF switch stacks are disclosed. The described devices utilize multiple discharge paths and/or less negative body bias voltages without compromising non-linear performance and power handling capability of power switches. Moreover, more compact bias voltage generation circuits with smaller footprint can be implemented as part of the disclosed devices.