Bootstrapped Self-Biasing Shunt Switch for Linearity-Resistance Tradeoff
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Solution Overview
Problem
Shunt switches for radio frequency, microwave, and mm-wave circuits face a trade-off between linearity and on-state resistance, with more transistors improving linearity but degrading resistance, and fewer transistors improving resistance but degrading linearity.
Innovation Solution
A self-biasing shunt switch with bootstrapping, comprising a transistor stack, a capacitor, and a bootstrapping transistor, which transitions to an on or off state based on signal power thresholds, using bias circuits to control gate and source voltages of the transistors, allowing for improved linearity and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a larger number of transistors are used in the shunt switch, then linearity is improved, but on-state resistance degrades
Solution Approach 1:
The shunt switch automatically detects signal power levels and adjusts its own bias state without external control. When signal power exceeds a threshold, the switch self-biases to the on-state, and when below the threshold, it self-biases to the off-state. This self-service mechanism eliminates the need for external bias control circuits while optimizing performance based on actual signal conditions.
Solution Approach 2:
The invention dynamically adjusts the bias state of the shunt switch based on signal power levels. The switch transitions between off-state (for low power signals to maintain linearity) and on-state (for high power signals to reduce resistance). This dynamic adaptation allows the switch to optimize both linearity and on-state resistance depending on operating conditions.
2Object-affected harmful factors
If a smaller number of transistors are used in the shunt switch, then on-state resistance is improved, but linearity degrades
Solution Approach 1:
The shunt switch dynamically changes its operational state based on signal power detection. For low power signals, it maintains an off-state with higher impedance to preserve linearity. For high power signals, it transitions to an on-state with lower resistance. This dynamic behavior allows a single switch configuration to achieve both low resistance and high linearity at different times.
Solution Approach 2:
The invention changes the bias parameter (gate voltage) of the transistor based on signal power levels. When signal power exceeds the threshold, the gate voltage changes to turn the transistor on, reducing on-state resistance. When below the threshold, the transistor remains off, maintaining better linearity. This parameter change allows the switch to optimize performance for different signal conditions.
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 self-biasing shunt switch achieves better linearity and on-state resistance compared to traditional switches, with faster transition times and reduced loss, enabling efficient signal transmission in 5G and mm-wave applications.
Implementation Method 1
a capacitor having a first terminal connected to the second end terminal of the transistor stack, and a second terminal connected to a low-impedance node
Implementation Method 2
a bootstrapping transistor connected across the first end terminal and a gate of the first transistor
Data Source
AI summary
A shunt switch. In some embodiments, the shunt switch includes a transistor stack including a first transistor and a capacitor. The transistor stack may have a first end terminal and a second end terminal, the first transistor being connected to the first end terminal, the first end terminal being connected to a switching terminal of the shunt switch. The capacitor may have a first terminal connected to the second end terminal of the transistor stack, and a second terminal connected to a low-impedance node.