Synchronous Flyback Converter with Detection Transformer
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Solution Overview
Problem
Existing synchronous flyback converter circuits face challenges in providing a cost-effective and space-efficient means to detect lamp path current for regulating electrical energy, making it difficult to integrate them into a chip for efficient lamp operation.
Innovation Solution
A synchronous flyback converter circuit with a detection circuit that includes a detection transformer and a signal generation unit, which evaluates the relative temporal position of detection pulses to generate a signal representing the lamp path current, allowing for potential-separated detection and feedback regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a detection circuit is added to detect lamp path current for feedback regulation, then the electrical energy regulation capability is improved, but the device complexity and space occupation increase
Solution Approach 1:
A detection transformer is introduced as an intermediary component to detect the lamp path current. The detection transformer couples to the lamp path and generates a detection signal proportional to the current, which is then fed back to the control unit. This intermediary approach enables current detection without direct electrical connection to the high-voltage lamp path, improving safety and isolation while enabling feedback regulation.
Solution Approach 2:
The detection transformer creates a copied or scaled version of the lamp path current signal. Instead of directly measuring the high-voltage lamp path current, the system uses the detection transformer to generate a low-voltage copy of the current waveform, which can be safely processed by the control circuitry. This copying principle allows accurate current sensing while maintaining galvanic isolation.
2Reliability
If a detection transformer is used for current detection, then the galvanic isolation is improved, but the device area and cost increase
Solution Approach 1:
The detection transformer serves as a galvanic isolation intermediary between the high-voltage lamp path and the low-voltage control circuitry. It transfers current information through magnetic coupling without direct electrical connection, ensuring safe isolation while enabling feedback control. The transformer's magnetic core and windings provide the isolation barrier.
Solution Approach 2:
The system replaces direct electrical measurement with magnetic field-based detection. Instead of using electrical contacts or conductive paths to sense the lamp path current, the detection transformer uses electromagnetic induction to sense current through its magnetic field, providing inherent galvanic isolation while enabling accurate current measurement.
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 simple and cost-effective detection of lamp path current, facilitating efficient regulation of electrical energy and integration into a chip for improved lamp operation.
Implementation Method 1
detection circuit (2) for generating a signal (SQ) that represents the lamp path current (iLED) flowing through the lamp path (4) when the lamp path (4) is connected to the secondary winding (Ns1)
Implementation Method 2
a transformer (T1) with a primary winding (Np1), which is electrically connected to the controllable switch (S1), and a secondary winding (Ns1)
Data Source
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AI summary
The present invention relates to a synchronous flyback converter circuit (1) for operating an illuminant string (4) comprising at least one illuminant (5), in particular comprising at least one light emitting diode, wherein the synchronous flyback converter circuit (1) comprises a detection circuit (2) for generating a signal (SQ) representing the illuminant string current (iLED) flowing through the illuminant string (4); wherein the detection circuit (2) comprises: a detection secondary winding (Ns2) of a detection transformer (T2), said detection secondary winding being arranged on the primary side (PS) of the flyback converter circuit, said detection transformer having a detection primary winding (Np2) arranged on the secondary side (SS) of the flyback converter circuit and electrically connected in series with the output (A1, A1') of the flyback converter circuit (1), wherein the detection transformer (T2) is configured in such a way that the detection transformer (T2) is operated at saturation by the illuminant string current (iLED). The invention furthermore relates to a luminaire having such a synchronous flyback converter circuit according to the invention and an illuminant string comprising at least one illuminant (5), in particular comprising at least one light emitting diode; and to a method for operating such a synchronous flyback converter circuit according to the invention, in particular a method for detecting the illuminant string current (iLED) in the case of such a synchronous flyback converter circuit according to the invention.