Galvanic Isolated Feedback Circuit Using Hall Sensor and Inductor
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Solution Overview
Problem
Conventional switched mode power supply circuits are complex due to the use of multiple integrated circuits and require significant space, primarily because they need to maintain galvanic isolation between voltage domains while controlling output voltage.
Innovation Solution
The implementation of a galvanic isolated feedback circuit with an on-chip inductor and Hall sensor, integrated within a single chip, reduces complexity and space requirements by using a switching regulator connected to the primary winding of the transformer, where the output voltage is rectified and applied to the inductor to generate a magnetic field measured by the Hall sensor, and an overcurrent protection circuit is included for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional galvanic isolated feedback circuit with optocoupler is used, then safety and galvanic isolation are ensured, but device complexity and space requirements increase
Solution Approach 1:
The patent combines the Hall sensor, inductor, and voltage amplifier into a single integrated feedback circuit chip, replacing the conventional separate optocoupler, error amplifier, and switching regulator components. This merging reduces the number of discrete components while maintaining galvanic isolation through magnetic coupling between primary and secondary windings.
Solution Approach 2:
The integrated feedback circuit chip performs multiple functions simultaneously: the Hall sensor detects magnetic field, the inductor stores energy and transforms voltage, and the voltage amplifier conditions the output signal. This multi-functional integration eliminates the need for separate dedicated components for each function.
2Reliability
If conventional galvanic isolated feedback circuit with multiple integrated circuits is used, then galvanic isolation is maintained, but the required space increases
Solution Approach 1:
The patent integrates the Hall sensor, inductor, and voltage amplifier onto a single chip, dramatically reducing the PCB footprint. The magnetic coupling between primary and secondary windings provides galvanic isolation without requiring separate optocoupler components, thereby minimizing the overall circuit board area.
3Ease of operation
If conventional switched mode power supply circuit with three integrated circuits is used, then voltage control is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent consolidates three separate integrated circuits (optocoupler, error amplifier, switching regulator) into a single integrated feedback circuit chip. This reduces assembly steps, minimizes soldering operations, and simplifies manufacturing while preserving the voltage control functionality through integrated Hall sensor-based feedback.
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 simplifies the switched mode power supply circuit, reduces its size, and enhances efficiency by integrating all necessary components into a single chip, providing effective voltage control and overcurrent protection while maintaining galvanic isolation.
Implementation Method 1
the feedback circuit comprises a Hall sensor to measure an internal magnetic field generated by an inductor
Implementation Method 2
the output voltage at the secondary winding of the transformer is rectified and applied to a first terminal of the inductor via a resistor defining an electrical current flowing through said inductor to generate the magnetic field
Data Source
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AI summary
A switched mode power supply, SMPS, circuit (1) comprising a transformer (4) configured to convert an input voltage (Vin) applied to a primary winding (5) of the transformer (4) into an output voltage at a secondary winding (6) of the transformer (4), a galvanic isolated feedback circuit (10) configured to control the output voltage at the secondary winding (6) of the transformer (4), wherein the galvanic isolated feedback circuit (10) comprises an inductor (13) to which the output voltage of the secondary winding (6) of the transformer (4) is applied to generate a magnetic field measured by a Hall sensor (13) of that galvanic isolated feedback circuit (10) to provide a control voltage used to control the output voltage at the secondary winding (6) of the transformer (4). The output voltage at the secondary winding can be constant, but changing the duty cycle controls the output voltage of the whole device.