Gate-Shunted T-Switch Topology for Parasitic RF Path Cancellation
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Solution Overview
Problem
Current wireless communication systems face challenges in isolating higher frequency signals effectively due to parasitic capacitances, leading to interference and concurrency issues in compact designs, particularly in multi-generational devices supporting multiple communication standards like 5G New Radio.
Innovation Solution
The implementation of a t-switch with gate shunting, which includes a shunt capacitor and shunt switches, enhances isolation by canceling parasitic transmission path signals across the differential signal path or to a reference potential, improving the performance of receiver switch matrix circuits and wireless transceivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact design is used to support multiple communication standards, then device size and integration are improved, but isolation between higher frequency signals deteriorates due to parasitic capacitances
Solution Approach 1:
The patent converts the harmful parasitic capacitances into beneficial isolation mechanisms by introducing shunt switches and shunt capacitors that actively cancel parasitic transmission paths. The shunt switches are configured to shunt parasitic signals to ground, transforming the parasitic capacitance from a source of interference into a controlled element that enhances isolation between frequency bands and communication standards in compact multi-generational devices
2Reliability
If isolation between receive channels is improved, then receiver sensitivity is improved, but device complexity increases due to additional shunt switches and capacitors
Solution Approach 1:
The shunt switches and shunt capacitors are designed to serve multiple functions simultaneously: they provide isolation between different receive channels, cancel parasitic transmission paths across differential signal paths, and maintain signal integrity across multiple frequency bands. This multi-functionality allows the circuit to achieve improved receiver sensitivity without proportionally increasing complexity, as the same components address multiple interference mechanisms
3Object-affected harmful factors
If shunt switches are used to cancel parasitic signals, then isolation is improved, but power consumption increases due to additional switching operations
Solution Approach 1:
The shunt switches are controlled to operate periodically based on the communication mode and frequency band being used, rather than remaining continuously active. The control circuitry enables or disables the shunt switches depending on whether parasitic cancellation is needed for the current operating conditions, thereby reducing unnecessary power consumption while maintaining effective parasitic signal cancellation when required
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 solution increases isolation and reliability, enabling concurrency scenarios and flexibility in band and carrier aggregation, reducing interference and signal degradation, and improving throughput in devices with marginal interference.
Implementation Method 1
a shunt capacitor coupled between a first input of the first differential output and a second input of the first differential output, wherein the shunt capacitor is further coupled between a first input of the second differential input and a second input of the second differential input
Implementation Method 2
a first shunt switch having a third control input, a third input, and a third output, wherein the third input and the third output are coupled across the first control input
Data Source
AI summary
Aspects of the disclosure relate to devices, wireless communication apparatuses, methods, and circuitry for a t-switch with gate shunting. One aspect is an apparatus including a first differential switch having a control input. The apparatus further includes a second differential switch coupled to the first differential switch, the second differential switch a control input. A shunt capacitor is coupled between a first output and a second output of the first differential switch, and a first input and a second input of the second differential switch. A first shunt switch having a control input, an input, and an output has the input and the output coupled to the control input of the first differential switch. A second shunt switch having a control input, an input, and an output, has the input and the output coupled to the control input of the second differential switch.