Self-Resonant Voltage Boost Circuit for Ultra-Low Energy Harvesting
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Solution Overview
Problem
Existing voltage boost circuits struggle to effectively boost ultra-low input voltages, such as those generated by thermoelectric devices, which are below 0.6 volts, as they require external oscillators and capacitive coupling, limiting their efficiency and applicability.
Innovation Solution
A self-resonance based voltage boost circuit using a single depletion mode junction field effect transistor (JFET) to initiate oscillations, coupled with N-channel and P-channel MOSFETs for enhanced power transfer, allowing efficient voltage boosting from as low as 20 millivolts without external excitation, and capable of operating in push/pull mode for full-wave energy extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional voltage boost circuits are used, then voltage boosting capability is achieved, but external oscillators and capacitive coupling are required, increasing circuit complexity
Solution Approach 1:
The circuit uses a depletion mode JFET that automatically generates oscillations through self-resonance without requiring external oscillators. The JFET's unique property of conducting at zero gate voltage allows it to self-oscillate and drive the voltage boosting process, eliminating the need for external excitation sources and reducing circuit complexity.
Solution Approach 2:
The circuit exploits the unique electrical characteristics of depletion mode JFETs, which conduct current at zero gate voltage unlike enhancement mode transistors. This parameter difference enables the JFET to oscillate at ultra-low input voltages (as low as 20 millivolts) and automatically regulate the oscillation amplitude, eliminating the need for external oscillators and capacitive coupling.
2Use of energy by moving object
If external oscillators are used to drive transistor switches, then voltage boosting is achieved, but the circuit cannot operate at ultra-low voltages below 0.6 volts
Solution Approach 1:
The depletion mode JFET serves itself by generating oscillations internally through self-resonance. It does not require external oscillators or capacitive coupling to initiate and sustain oscillations, enabling operation at ultra-low voltages below 0.6 volts where conventional circuits fail.
Solution Approach 2:
The depletion mode JFET acts as an intermediary between the ultra-low voltage source and the voltage boosting mechanism. Its unique ability to conduct at zero gate voltage allows it to amplify the ultra-low input signal and drive the oscillating circuit without requiring external excitation.
3Productivity
If thermoelectric generators operate with low temperature gradients, then energy extraction is possible, but the generated voltage is too low for practical use
Solution Approach 1:
The circuit uses self-resonance oscillations generated by the depletion mode JFET to efficiently transfer power from the ultra-low voltage thermoelectric generator to the output. The oscillating current at resonance frequencies maximizes power transfer efficiency, enabling practical energy extraction even when the temperature gradient is small and the generated voltage is only 20 millivolts or less.
Solution Approach 2:
The circuit transforms the ultra-low voltage output from thermoelectric generators into higher usable voltages through the self-oscillating voltage boosting mechanism. The depletion mode JFET's unique electrical characteristics enable this transformation to occur efficiently at input voltages as low as 20 millivolts, making previously unusable low-gradient thermoelectric energy harvestable.
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 enables efficient conversion of ultra-low input voltages to higher usable voltages, reducing circuit complexity, eliminating the need for external power sources, and allowing practical energy extraction from thermoelectric generators even with low temperature gradients, while maintaining high efficiency and versatility across input polarities.
Implementation Method 1
A self-resonance based voltage boost circuit using a single depletion mode junction field effect transistor (JFET) to initiate oscillations
Implementation Method 2
The generated voltage from a thermoelectric device is proportional to the temperature across the device
Data Source
AI summary
A circuit for boosting the voltage from a very low level voltage source to a higher level voltage output utilizing self-oscillation.