Zero-Crossing Detector Circuit Power Reduction
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Solution Overview
Problem
Existing zero-crossing detector circuits for AC voltage, such as those using photocouplers, consume significant power, necessitating a more energy-efficient solution for detecting zero-crossing points.
Innovation Solution
A zero-crossing detector circuit utilizing a first and second capacitor, a current path, and a signal converter circuit, configured with a transistor and diode, to generate a pulse signal for detecting zero-crossing points, reducing current flow and power consumption compared to traditional photocoupler-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photocoupler is used to detect zero-crossing points, then zero-crossing detection is achieved, but power consumption increases
Solution Approach 1:
The invention extracts and removes the photocoupler component from the zero-crossing detection circuit. Instead of using a photocoupler, the patent employs a simpler circuit configuration using a capacitor, diode, and transistor that can detect zero-crossing points without the need for the photocoupler's photodiode, thereby eliminating its power consumption
Solution Approach 2:
The invention creates a functional copy of the zero-crossing detection capability using different components. The capacitor-diode-transistor circuit replicates the zero-crossing detection function previously achieved by the photocoupler, but with significantly lower power consumption since it doesn't require driving a photodiode
Data Source
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AI summary
A zero-crossing detector circuit includes: a first capacitor including a first electrode configured to connect to one end of an AC power supply and a second electrode; a second capacitor including a first electrode configured to connect to the other end of the AC power supply and a second electrode; a current path, which is connected in series between the second electrode of the first capacitor and the second electrode of the second capacitor, and which is connected to a reference potential, and which generates a second-electrode-side voltage when the AC current passes through the current path; a signal converting circuit, which is connected to the AC power supply to receive the second-electrode-side voltage and then converts the second-electrode-side voltage into a pulse signal; and a detecting unit, which detects a pulse period of the pulse signal, which and detects zero-crossing points by using the pulse period.