RF Switch Circuit Topology for Uniform ESD Switching Voltage
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Solution Overview
Problem
Radio frequency switch circuits face challenges in dissipating electrostatic discharge (ESD) due to voltage transient changes, resulting in uneven switching voltages across transistors, which affects their response and ESD dissipation capability.
Innovation Solution
A radio frequency switch circuit design featuring two series connection groups with transistors, where control terminals of each group are coupled to separate control nodes, ensuring different voltages during ESD events, thus maintaining relatively uniform switching voltages and enhancing ESD dissipation capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transistors are connected in series with commonly coupled control terminals, then the circuit structure is simple, but the switching voltages become uneven during ESD events
Solution Approach 1:
The patent divides the series circuit into multiple groups, where each group has its own control terminal. This segmentation allows different control voltages to be applied to different groups, enabling independent optimization of switching behavior for each group during ESD events while maintaining overall circuit functionality.
Solution Approach 2:
The patent applies different control voltages to different groups of transistors based on their specific positions and ESD exposure conditions. Groups closer to the ESD entry point receive higher control voltages, while groups farther away receive lower control voltages, creating a localized quality distribution that optimizes switching uniformity across the entire series circuit.
2Quantity of substance
If the number of transistors in series increases, then the voltage division effect becomes more pronounced, but the switching voltage difference between transistors increases
Solution Approach 1:
By segmenting the large number of series transistors into multiple groups with separate control terminals, the patent prevents the cumulative voltage division effect from causing excessive switching voltage differences. Each group can be controlled independently, ensuring consistent switching responses even when the total number of transistors is large.
Solution Approach 2:
The patent changes the control voltage parameter for different groups of transistors based on their position in the series connection. This parameter adjustment compensates for the voltage division effect, ensuring that all transistors switch uniformly regardless of the total number of transistors in the circuit.
3Device complexity
If commonly coupled control terminals are used, then the control signal distribution is simple, but the ESD dissipation capability is reduced
Solution Approach 1:
The patent segments the control signal distribution into multiple independent control terminals, each managing a specific group of transistors. This segmentation enables optimized ESD protection for each group, improving overall ESD dissipation capability while maintaining reasonable control signal distribution complexity.
Solution Approach 2:
The patent applies different control voltages to different groups based on their local ESD exposure conditions. Groups experiencing higher ESD stress receive appropriate control voltages to ensure proper switching, thereby enhancing the overall ESD dissipation capability of the 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
The design improves the uniformity of switching voltages across transistors, enabling them to respond consistently to ESD events and enhance the circuit's ESD dissipation capability.
Implementation Method 1
the ESD voltage VESD may be coupled to the control terminals of the transistors T1 to T8 through the parasitic capacitance of the transistor T1
Implementation Method 2
the sources of the transistors T1 to T8 have different voltages based on voltage division of the transistors T1 to T8
Data Source
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AI summary
A radio frequency switch circuit (100) includes a series circuit (110_1 to 110_4, 210, 310, 410). The series circuit (110_1 to 110_4, 210, 310, 410) includes a first series connection group (211, 311, 411) and a second series connection group (212, 312, 412). The first series connection group (211, 311, 411) includes first transistors (T1_1 to T4_1). The second series connection group (212, 312, 412) includes second transistors (T1_2 to T4_2). When an electrostatic discharge event occurs, a voltage at control terminals of the first transistors (T1_1 to T4_1) are different from a voltage at control terminals of the second transistors (T1_2 to T4_2). In a normal operation state, switch states of the first series connection group (211, 311, 411) and the second series connection group (212, 312, 412) are the same as each other.