Rectifier Circuit With Biasing Networks For Low Voltage Harvesting
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Solution Overview
Problem
Existing energy harvesting systems face challenges in efficiently converting low input voltages into usable DC power due to the threshold voltage requirements of Schottky diode bridges, which limits their operation and is costly and area-consuming when magnetic elements are used.
Innovation Solution
A rectifier circuit with a diode-bridge configuration and parallel switches (MOSFETs) driven by biasing networks to enable conduction during positive and negative half-waves of the AC input signal, reducing the threshold voltage and allowing energy storage at lower input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Schottky diode bridge rectifier is used, then rectification can be achieved, but the input voltage must be higher than 2VD (threshold voltage), limiting operation at low input voltages
Solution Approach 1:
The patent introduces an intermediary circuit between the AC input and the Schottky diode bridge that generates a bias voltage to assist the diodes in conducting at lower input voltages. This intermediary mechanism allows the rectifier to operate below the normal 2VD threshold by providing an additional voltage boost during the rectification process.
Solution Approach 2:
The patent changes the operating parameters of the Schottky diodes by applying a bias voltage that modifies their threshold characteristics. By dynamically adjusting the bias voltage based on the input voltage level, the system enables rectification at input voltages lower than the standard 2VD requirement, effectively changing the diode conduction parameters.
2Adaptability or versatility
If magnetic elements are used to reduce threshold voltage, then low voltage operation is enabled, but the device becomes costly and area-consuming
Solution Approach 1:
The patent replaces magnetic elements (mechanical/physical components) with an electronic biasing circuit that uses voltage multiplication and switching. This substitution eliminates the need for bulky magnetic components while achieving the same effect of enabling low-voltage operation through electronic parameter control.
Solution Approach 2:
Instead of using magnetic elements to physically alter the threshold voltage, the patent changes the electrical parameters by introducing a bias voltage that dynamically adjusts the effective threshold. This parameter-based approach achieves low-voltage operation without the size and cost penalties of magnetic components.
3Reliability
If Schottky diodes are used, then rectification is achieved, but temperature dependence limits use to controlled-temperature environments
Solution Approach 1:
The patent incorporates temperature compensation through feedback mechanisms that monitor the diode threshold voltage variations and adjust the bias voltage accordingly. This feedback control counteracts temperature-induced threshold changes, maintaining stable rectification operation across a wider temperature range than conventional Schottky diode circuits.
4Power
If a diode bridge rectifier is used, then rectified output is generated, but energy is dispersed when input voltage is below threshold
Solution Approach 1:
The patent applies preliminary action by generating a bias voltage in advance that prepares the Schottky diodes for conduction before the input voltage would normally reach the threshold. This preliminary biasing ensures that rectification can begin immediately when the input voltage becomes available, preventing energy dispersion that would occur in conventional circuits operating below the threshold.
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 efficient rectification and energy storage at low input voltages, improving the continuity of operation and reducing the threshold voltage to approximately 0.1 V, allowing energy harvesting even at low input voltages, such as 1 V, and is integrated, reducing size and cost.
Implementation Method 1
The mechanical energy is converted, by one or more appropriate transducers (for example, piezoelectric or electromagnetic devices) into electrical energy
Implementation Method 2
The mechanical energy is converted, by one or more appropriate transducers (for example, piezoelectric or electromagnetic devices) into electrical energy
Implementation Method 3
The rectifier circuit comprises: four diodes electrically connected to one another to form a diode-bridge rectifier; four switches (in particular transistors, more in particular MOSFETs)
Data Source
AI summary
A rectifier circuit includes a first, second, third and fourth parasitic diodes electrically connected to form a full-wave diode-bridge rectifier. A first switch and a second switch are connected in parallel, respectively, to the first and second parasitic diodes, and a third switch and a fourth switch connected in parallel, respectively, to the third and fourth parasitic diodes. A first biasing network is configured to drive in conduction the first and second switches, during turning-on of the rectifier circuit, using a first turning-on signal that is a function of the input signal. A second biasing network is configured to close the third and fourth switches, during turning-on of the rectifier circuit, using a second turning-on signal that is a function of the input signal.