Switch Control Device Zero-Cross Point Estimation Edge Detection
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Solution Overview
Problem
Existing power switch control systems in LED light emitting devices face challenges in accurately detecting the zero cross-point of input voltage due to noise vulnerability, leading to malfunction.
Innovation Solution
A switch control device comprising a self-power voltage biasing circuit, a reference signal generator, and a PWM controller that uses edge detection and noise removal techniques to synchronize a reference signal with the input-terminal voltage, enabling accurate zero cross-point detection and noise-resistant switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage sensing is performed at the input terminal of the power switch, then input voltage information can be obtained for controlling switching operation, but noise interference occurs near zero voltage points causing inaccurate zero cross-point detection
Solution Approach 1:
The patent introduces an intermediary signal processing mechanism that senses voltage at the input terminal but processes it through a controlled switching framework. The power switch and control circuit act as intermediaries that filter and condition the noisy voltage signal, enabling accurate zero cross-point detection without directly using the raw noisy voltage information for switching control decisions.
Solution Approach 2:
The control circuit performs preliminary detection and processing of the voltage signal before the actual switching operation. By detecting the zero cross-point in advance and preparing control signals beforehand, the system avoids the noise problem during critical switching moments and ensures accurate timing for power switch operation.
2Productivity
If the power switch is controlled based on noisy voltage signals near zero cross-point, then switching operation can be maintained, but malfunction occurs due to inaccurate zero cross-point sensing
Solution Approach 1:
The patent implements a feedback mechanism where the control circuit continuously monitors the voltage signal and adjusts switching control based on detected zero cross-points. This feedback loop ensures that even when noise is present, the system can reliably determine zero cross-points and maintain proper switching operation, preventing malfunction while ensuring continuous productivity.
Solution Approach 2:
The control circuit prepares for potential noise interference by establishing robust detection thresholds and hysteresis mechanisms before noise affects the system. This cushioning approach creates a buffer zone around zero cross-points that prevents noise from causing false triggering or malfunction, ensuring reliable operation under noisy conditions.
Data Source
AI summary
Provided are a switch control device, a switch control method, and a power supply device. The present invention generates power voltage required to operate the switch control device by using full-wave current rectification voltage generated by rectifying an AC input and detects a zero cross-point when a full-wave rectification voltage is zero voltage by using the edge of power voltage. The present invention generates a reference signal synchronized to the full-wave rectification voltage by using the detected zero cross-point and controls a switching operation of a power switch by comparing a reference signal with current which flows on the power switch.