Integrated Circuit for AC Voltage Interruption Detection
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Solution Overview
Problem
Existing AC-DC converters require a large number of discrete components for detecting interrupted AC voltage, increasing their cost.
Innovation Solution
An integrated circuit with a rectifier circuit, an inductor, and a transistor that controls inductor current, including a signal output circuit with comparators and a timer to detect AC voltage interruption at a lower cost by comparing inductor current and output voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a detection circuit with a large number of discrete components is used to detect AC voltage interruption, then the detection accuracy is improved, but the cost of the AC-DC converter increases
Solution Approach 1:
The patent integrates the AC voltage interruption detection function into the existing power supply control circuit by sharing the comparator and timer resources. The comparator that normally compares inductor current with reference voltage is used to detect AC voltage interruption by comparing rectified voltage with a threshold, eliminating the need for separate discrete detection components and reducing overall cost while maintaining detection accuracy
Solution Approach 2:
The comparator circuit is designed to perform multiple functions: normal voltage regulation through current comparison, and AC voltage interruption detection through voltage level comparison. The timer circuit similarly serves both timing control and detection confirmation purposes. This multi-functionality reduces component count and manufacturing cost while preserving detection capability
2Ease of manufacture
If an integrated circuit is used to detect AC voltage interruption, then the cost is reduced, but the device complexity may increase
Solution Approach 1:
The detection circuit shares physical and functional resources with the power supply control circuit, including the comparator, timer, and associated signal processing elements. By merging these functions into a single integrated control IC rather than using discrete components, the patent reduces overall system complexity while maintaining low cost and accurate detection capability
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
Enables cost-effective detection of AC voltage interruption and restoration in AC-DC converters, improving power factor correction and reducing power consumption by using a single integrated circuit.
Implementation Method 1
a first comparator circuit that compares a value of the inductor current and a predetermined current value
Implementation Method 2
a timer circuit that measures a time elapsed since the first comparator circuit starts to output a result of the comparison
Implementation Method 3
a second comparator circuit that compares a level of the output voltage and a first level lower than the target level
Implementation Method 4
a rectifier circuit that rectifies the AC voltage
Implementation Method 5
an inductor that receives a rectified voltage from the rectifier circuit
Data Source
AI summary
An integrated circuit for a power supply circuit that generates an output voltage at a target level from an AC voltage input thereto. The power supply circuit includes an inductor, and a transistor that controls a current flowing through the inductor. The integrated circuit drives the transistor based on the inductor current and the output voltage. The integrated circuit has a signal output circuit including a first comparator circuit comparing the inductor current and a predetermined current value, a timer circuit measuring a time elapsed since the value of the inductor current becomes smaller than the predetermined current value, and a second comparator circuit comparing the output voltage and a lower-than-target level. The signal output circuit indicates that the AC voltage is not input to a rectifier circuit, when the elapsed time reaches a predetermined time period and a level of the output voltage is lower than the lower-than-target level.