Switch Mode Power Converter Circuit for Relay Control
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Solution Overview
Problem
Conventional power converters used in photo controllers are inefficient, generating high heat and requiring large packages with heat dissipating elements, and are cost-prohibitive due to the need for multiple transistors or a micro-controller, which affects reliability and longevity.
Innovation Solution
A small, low-cost, efficient switch mode power converter circuit is developed, utilizing a pulse width modulator and a Darlington pair of transistors to regulate the relay coil voltage, with a half-wave rectifier and a phototransistor to control the power signal based on light levels, reducing component count and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power converters use large high-voltage resistors to drop voltage, then voltage conversion is achieved, but heat generation increases and efficiency decreases
Solution Approach 1:
The patent replaces the conventional resistor-based voltage dropping mechanism with a switch-mode power converter that uses electromagnetic induction and magnetic fields. The transformer-based design substitutes thermal resistance dissipation with magnetic flux transformation, enabling efficient voltage conversion without significant heat generation from resistive losses.
Solution Approach 2:
The patent employs switching elements that rapidly transition between on and off states to control power flow. This phase transition approach allows the power converter to operate in discrete states, minimizing energy loss during transitions and maintaining high efficiency throughout the voltage conversion process.
2Loss of energy
If switch mode power converters use multiple transistors or micro-controllers, then power conversion efficiency improves, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple functions into integrated circuits and unified power converter modules. By merging the switching elements, transformer connections, and control logic into a compact integrated design, the patent achieves efficient power conversion while reducing the overall component count and simplifying the device architecture.
Solution Approach 2:
The patent designs a universal power converter topology that can handle various voltage levels and load conditions through a single integrated circuit design. This multi-functional approach eliminates the need for separate transistor stages for different operating modes, reducing complexity while maintaining efficiency across diverse applications.
3Power
If high heat is generated by resistors, then voltage dropping is achieved, but reliability and longevity of components decrease
Solution Approach 1:
The patent substitutes the thermal-based voltage dropping method with an electromagnetic field-based approach using transformers. This substitution eliminates the heat generation that causes component degradation and extends the operational life of electronic components by maintaining lower operating temperatures throughout the system.
Solution Approach 2:
The patent converts the potentially harmful heat generation issue into a beneficial cooling effect through the transformer's magnetic flux. The alternating magnetic field induces currents that naturally cool the transformer windings, transforming what would be a heat problem into a thermal management advantage that protects components from thermal damage.
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 provides a reliable, efficient, and cost-effective power conversion system that effectively controls light levels in photo controllers, reducing heat and component count, thereby improving longevity and reducing operational costs.
Implementation Method 1
A photo control circuit is configured to control application of the pulse width modulated signal to the drive transistor responsive to a detected light level
Implementation Method 2
A power circuit includes a half-wave rectifier coupled to the power source that is configured to provide a power signal to the pulse width modulator circuit
Implementation Method 3
utilizing a pulse width modulator and a Darlington pair of transistors to regulate the relay coil voltage
Implementation Method 4
A pulse width modulator circuit is configured to generate a pulse width modulated signal having a pulse width that varies responsive to an average voltage across the relay coil
Data Source
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AI summary
Photosensor circuits include a relay coil configured to control application of an alternating current (AC) power source to a load. The circuit includes a pulse width modulator circuit configured to generate a pulse width modulated signal having a pulse width that varies responsive to an average voltage across the relay coil. A drive transistor is coupled between the relay coil and a neutral bus that controls the average voltage across the relay coil responsive to the pulse width modulated signal. A photo control circuit is configured to control application of the pulse width modulated signal to the drive transistor responsive to a detected light level. A power circuit includes a half-wave rectifier coupled to the power source that is configured to provide a power signal to the pulse width modulator circuit and a regulated power signal to the photo control circuit. The power signal is a square wave and the power circuit further includes a rectifier circuit and a voltage divider circuit configured to generate the regulated power signal from the power signal. The photo control circuit includes a phototransistor. The phototransistor has a first terminal coupled to the regulated power signal through a first resistor and a second terminal that outputs a current responsive to a level of light detected by the phototransistor. A low pass filter circuit is coupled to the first terminal of the phototransistor that filters the output current of the phototransistor to provide a light level signal voltage and a select transistor couples the pulse width modulated signal to the drive transistor responsive to the light level signal voltage having a selected level.