Bootstrapped Switch Gate Boosting for Fast Static-Bias Switching
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Solution Overview
Problem
Conventional bootstrapped switches with complex designs struggle to achieve fast ON/OFF speed when operating with static bias voltages, which is a requirement for high-speed applications.
Innovation Solution
A simplified bootstrapped switch design that includes a first transistor, a capacitor, a first voltage providing circuit, and a second voltage providing circuit. The first voltage providing circuit switches between two voltages based on the transistor's ON/OFF state, and the second voltage providing circuit applies a boost voltage during the transistor's OFF period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If device sizes are increased to reduce MOS on-resistance, then switching speed is improved, but parasitic capacitance increases which limits switching speed
Solution Approach 1:
The patent changes the voltage parameter applied to the gate terminal by using a bootstrapping mechanism that dynamically adjusts the gate voltage based on the input signal voltage. This allows the transistor to operate with optimized effective voltage differences, reducing the need for large device sizes and minimizing parasitic capacitance effects while maintaining fast switching speed.
2Reliability
If conventional bootstrapped switch design is used to minimize MOS switch on-resistance variation, then distortion is reduced, but gate voltage exceeds supply voltage causing reliability issues
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy storage element between the input signal and the gate terminal. This capacitor mediates the voltage transfer, allowing the gate to receive the necessary bootstrapped voltage without directly exceeding the supply voltage limits, thus maintaining reliability while simplifying the overall design.
Solution Approach 2:
The patent applies preliminary charging to the capacitor during specific phases of operation, preparing the voltage condition in advance before it is needed at the gate terminal. This preliminary action ensures that when the transistor needs to switch, the gate already has the appropriate voltage level, avoiding the need for complex real-time voltage regulation circuits.
3Speed
If conventional bootstrapped switch with complex design is used, then bootstrapping function is achieved, but switching speed depends on MOS resistance and parasitic capacitance limiting high-speed performance
Solution Approach 1:
The patent extracts and isolates the essential bootstrapping function into a simple capacitor-gate configuration, removing unnecessary complex circuits from the conventional design. By taking out only the critical voltage storage and transfer mechanism, the design achieves fast switching speed while minimizing complexity, making it suitable for high-speed applications with static bias voltages.
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 simplified design achieves fast ON/OFF switching speeds, reduces chip area and power consumption, and is less sensitive to jitter, making it suitable for high-speed applications.
Implementation Method 1
The capacitor has a first end and a second end, wherein the first end is coupled to the control terminal of the first transistor
Data Source
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AI summary
A bootstrapped switch includes a first transistor, a capacitor, a first voltage providing circuit, and a second voltage providing circuit. Regarding the first transistor, a first connection terminal receives a static bias voltage, and a second connection terminal generates an output voltage. A first end of the capacitor is coupled to a control terminal of the first transistor. The first voltage providing circuit provides a first voltage to a second end of the capacitor during a first period in which the first transistor is turned off, and provides a second voltage to the second end of the capacitor during a second period in which the first transistor is turned on. The second voltage providing circuit provides a boost voltage to the control terminal of the first transistor during the first period, and stops providing the boost voltage to the control terminal of the first transistor during the second period.