Bootstrapped Switch Circuit for High-Swing Signal Control

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Solution Overview

Problem

Circuits face challenges in meeting competing operational requirements such as low voltage operation, noise generation, and bandwidth limitations, particularly when handling signals with high voltage swings and frequencies.

Innovation Solution

A circuit architecture incorporating a boot-strap design with charge harvesting and shutoff mechanisms to manage signal passage and blocking, using transistors, capacitors, and diodes to maintain charge and control signal transmission across a wide frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a switch circuit is used to pass or block signals, then signal transmission control is achieved, but charge leakage occurs at the control terminal and voltage supply requirements increase

Engineering Contradiction:

Improvesignal transmission controlVSAvoidcharge leakage

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The charge harvesting circuit recovers energy from the signal passing through the switch circuit and uses it to maintain the charge at the control terminal, making the system self-sufficient and eliminating the need for additional power supply connections

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The circuit recovers charge that would otherwise be lost through leakage at the control terminal by harvesting energy from the signal current flowing through the switch circuit, converting waste energy into useful charge maintenance

Inventive Principle:

Principle #34Discarding and recovering

2Use of energy by moving object

If the switch circuit operates with low voltage supply, then power consumption is reduced, but the circuit cannot handle signals with high voltage swings

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage swing handling capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The boot-strap architecture creates a second voltage dimension by generating a boosted voltage at the control terminal that exceeds the supply voltage, allowing the circuit to handle high voltage swing signals while maintaining low power consumption at the supply voltage level

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Speed

If the switch circuit passes high frequency signals, then bandwidth is increased, but charge leakage increases and control stability decreases

Engineering Contradiction:

Improvesignal frequency bandwidthVSAvoidcharge leakage

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The charge harvesting circuit continuously replenishes charge at the control terminal during signal transmission, maintaining stable control voltage even during high frequency operation where charge leakage would normally accumulate

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The circuit uses the signal current flowing through the switch as feedback to continuously charge the control terminal, creating a self-regulating mechanism that maintains stability during high frequency operation

Inventive Principle:

Principle #23Feedback

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 solution enables the passage or blocking of signals with peak-to-peak voltages exceeding supply voltage levels while minimizing noise and maintaining operational bandwidth, suitable for sensitive systems like medical devices.

Implementation Method 1

The first capacitor has a first terminal coupled to a voltage terminal, and having a second terminal. The second capacitor has a first terminal coupled to the second terminal of the first capacitor, and having a second terminal coupled to the second terminal of the first transistor and to the first terminal of the second transistor.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The first diode has a first anode and a first cathode, the first anode is coupled to the second terminal of the first capacitor and to the first terminal of the first capacitor, and the first cathode is coupled to the input of the shutoff circuit.

Methodology Applied

Scientific EffectDiode rectification: Diode

Implementation Method 3

The shutoff circuit has an input and including a first transistor having a control terminal and first and second terminals. The switch circuit includes at least a second transistor having a control terminal and first and second terminals, the control terminal of the second transistor is coupled to the first terminal of the first transistor, and the first terminal of the second transistor is coupled to the second terminal of the first transistor.

Methodology Applied

Scientific EffectField effect transistor conduction:

Data Source

PatentUS20260058655A1Switch circuit control

Publication Date: 2026.02.26 TEXAS INSTRUMENTS INC

AI summary

In some examples, an apparatus includes a switch circuit, a charge circuit, and a shutoff circuit. The switch circuit is configured to control passage of a data signal having a frequency of less than about 10 kilohertz (kHz) from an input terminal to an output terminal, the switch circuit having a control terminal. The charge circuit is coupled to a voltage supply and the switch circuit, wherein the charge circuit is configured to harvest a portion of current flowing through the switch circuit between the input terminal and the output terminal to maintain a charge at the control terminal greater than a programmed amount in a first state of operation and prevent charge from leaking from the control terminal. The shutoff circuit is coupled to the switch circuit and configured to discharge the charge at the control terminal in a second state of operation.