Photosensor Circuit Regulated Power Supply Heat Reduction
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Solution Overview
Problem
Conventional photosensor circuits for light level switching control face inefficiencies due to high heat generation from large resistors and the cost-prohibitive requirement of multiple transistors or micro-controllers in switch mode power converters, leading to reliability and longevity issues.
Innovation Solution
A photosensor circuit with a pulse width modulator and a microcontroller that generates a pulse width modulated signal to control a relay coil, using a power circuit with a drive transistor and a second transistor to regulate power, allowing for efficient and cost-effective control of AC power application based on detected light levels, eliminating the need for high-voltage resistors and reducing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If large high-voltage resistors are used to drop voltage in conventional power converters, then voltage conversion is achieved, but heat generation increases and efficiency decreases
Solution Approach 1:
The patent replaces the mechanical/resistive voltage dropping method with an electronic switch-mode power converter using transistors and a microcontroller. This substitution eliminates the need for large power-dissipating resistors and achieves voltage conversion through electronic switching, dramatically reducing heat generation and energy loss.
Solution Approach 2:
The patent changes the operating parameters from continuous resistive voltage dropping to pulsed switch-mode operation. By controlling the duty cycle of the switching transistor, the circuit achieves efficient voltage conversion while minimizing power dissipation, transforming the fundamental mode of operation from high-loss to low-loss.
2Loss of energy
If switch mode power converters are implemented using six transistors or a micro-controller, then efficient power conversion is achieved, but implementation cost increases
Solution Approach 1:
The patent merges the functions of multiple transistors and the microcontroller into a single integrated circuit. This consolidation maintains the efficient switch-mode power conversion functionality while reducing component count, simplifying the circuit design, and lowering implementation cost.
Solution Approach 2:
The integrated circuit performs multiple functions: it acts as the switching element, the control logic (microcontroller equivalent), and the power management unit all in one component. This multi-functionality eliminates the need for separate transistors and control circuitry, reducing device complexity while maintaining efficiency.
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 photosensor circuit capable of controlling AC power with reduced heat generation and extended component lifespan, supporting higher frequency operations and longer device life, suitable for applications like street lighting.
Implementation Method 1
a photosensor circuit including a phototransistor, a relay coil, a pulse width modulator
Data Source
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 coupled to the relay coil 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 coupled to the power source is configured to provide a regulated power signal to a comparator of the pulse width modulator circuit.