Primary-Side LED Charge Status Indicator Circuit
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Solution Overview
Problem
Traditional AC-DC chargers with secondary-side feedback control Flyback SMPS are inefficient and costly due to excessive components, and cannot be used with primary-side feedback control Flyback SMPS, as they result in higher no-load voltages and low efficiency.
Innovation Solution
A charger with a charge status indicator circuit comprising a detecting chip connected between the primary winding of the transformer and ground, a display module, and a comparing module that determines charging status using a frequency-electrical signal converter and error amplifier, allowing for efficient power conversion and reliable charge status display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional secondary-side feedback control circuit is used, then charge status indication is achieved, but device complexity increases and reliability decreases
Solution Approach 1:
The patent extracts the charge status detection function from the traditional complex circuit and implements it within the primary control side using the existing primary auxiliary winding. The detecting chip integrates the detection functionality, eliminating the need for separate detection components like resistors 219, diode 220, transistor 222, and capacitor 213, thereby reducing device complexity while maintaining indication reliability.
Solution Approach 2:
The patent makes the primary auxiliary winding serve multiple functions: it provides feedback voltage for primary-side feedback control and simultaneously serves as the detection source for charge status indication. This multi-functional usage eliminates the need for separate detection components, reducing device complexity while ensuring reliable charge status indication.
2Loss of energy
If traditional detection circuit with resistors and diodes is used, then charge status is detected, but power conversion efficiency decreases
Solution Approach 1:
The patent enables the primary auxiliary winding to self-serve dual purposes: providing feedback for power control and serving as the detection source for charge status. By using the inherently generated feedback voltage without requiring additional detection components, the system achieves accurate charge status detection while minimizing energy loss, as no additional current paths through resistors or diodes are created.
3Loss of energy
If traditional circuit with voltage drop detection is used, then charge status indication is achieved, but power conversion efficiency is reduced
Solution Approach 1:
The patent utilizes the feedback voltage from the primary auxiliary winding, which is inherently generated during normal operation, to determine charge status. The detecting chip monitors this feedback voltage to identify different charging stages (constant current, constant voltage, and full charge). This feedback-based approach eliminates the need for additional current paths through detection components, ensuring accurate charge status indication while maintaining high power conversion 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
Enables efficient power conversion and reliable charge status indication in primary-side feedback control Flyback SMPS, reducing component count and costs while maintaining high efficiency.
Implementation Method 1
a detecting chip for monitoring charge status connected between the primary winding of transformer and ground
Implementation Method 2
a frequency-electrical signal converter for converting the working frequency to an electrical signal which is proportional to the charging current
Implementation Method 3
an error amplifier for comparing the sample electrical signal with a reference value and outputting an electrical signal which is proportional to the charging current
Data Source
AI summary
The present invention relates to a charge status indicator and a charger. The charger comprises a charging power supply and a charge status indicator, wherein, the charge status indicator comprises a detecting chip for monitoring charge status connected between the primary winding of transformer and ground, and a display module used for displaying the charge status, wherein, said detecting chip for monitoring charge status comprising: a detecting module for detecting the charging state of the charge power supply; a comparing module for determining the current charge status based on the detected charging state. By employing the charger or the charge status indicator for a charger, a primary-side feedback control Flyback SMPS may be employed, just a simple and reliable circuit is needed, and higher efficient can be achieved.