Power Factor Correction Circuit Eliminating Optical Coupler
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Solution Overview
Problem
Conventional power factor correction (PFC) control circuits in power adapters suffer from high costs, increased volume due to the use of optical couplers, and higher total harmonic distortion (THD) leading to inefficient energy utilization and lower power factor properties.
Innovation Solution
A PFC circuit comprising a sampler, a controller with error amplification, peak value adjustment, ON/OFF computing, and phase lock units, and a current limiter, which omits the optical coupler and includes a filter circuit to reduce harmonic distortion, enhancing power factor correction and energy utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an optical coupler is used in the PFC control circuit, then over-current protection is achieved, but the volume and manufacturing cost increase
Solution Approach 1:
The patent removes the optical coupler from the PFC control circuit, extracting this component that causes increased volume and cost while maintaining over-current protection functionality through alternative circuit design using the controller directly
Solution Approach 2:
The controller is designed to perform multiple functions including over-current protection, pulse width modulation, and power factor correction control without requiring separate dedicated components like optical couplers, achieving multi-functionality with reduced circuit complexity
2Measurement precision
If multiplication circuits are used in the PFC control circuit, then control precision is improved, but total harmonic distortion increases and power factor deteriorates
Solution Approach 1:
The patent replaces traditional multiplication circuits with a control approach using the controller to directly generate PWM signals based on feedback, substituting complex analog multiplication operations with digital control logic that avoids generating input voltage harmonics
3Reliability
If conventional PFC control circuit design is used, then over-current protection is provided, but energy utilization efficiency decreases
Solution Approach 1:
The patent implements a feedback mechanism where the controller receives feedback signals from the circuit and adjusts the PWM output accordingly, enabling precise control of the power factor correction while maintaining over-current protection and improving energy utilization efficiency through continuous monitoring and adjustment
Data Source
AI summary
Disclosed are a power factor correction circuit and a power adapter, and the power factor correction circuit includes a sampler, a controller and a current limiter, and the controller includes an error amplification unit, a peak value adjusting unit, an ON/OFF computing unit and a phase lock unit. The sampler is coupled to the phase lock unit, and the current limiter is coupled to the error amplification unit and the ON/OFF computing unit, so as to achieve the effects of enhancing the power factor property of the power factor correction circuit, lowering the manufacturing cost, and improving the electric power utilization.