Isolated LED Converter With Primary-Side VCO Sensing
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Solution Overview
Problem
Implementing additional control logic on the secondary side of LED drivers with SELV capabilities increases complexity and cost due to the need for isolation between the primary and secondary sides.
Innovation Solution
An isolated converter design with a voltage-controlled oscillator (VCO) on the primary side and a control circuit on the secondary side, utilizing a galvanic isolation barrier to transmit voltage sensing signals across, eliminating the need for a secondary side control circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional control logic (microcontroller) is implemented on the secondary side to receive communication signals, then the capability to receive communication signals on the secondary side is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the communication signal reception capability into the existing primary side control logic. The primary side microcontroller handles both mains voltage monitoring and DALI communication signals, eliminating the need for a separate secondary side control logic. This is achieved by using the existing isolated communication interface to transmit DALI signals across the isolation barrier to the primary side controller.
Solution Approach 2:
The primary side control logic is designed to perform multiple functions: it monitors mains supply voltage, controls the LED driver operation, and receives DALI communication signals. This multi-functional approach allows a single control circuit to handle all control and communication tasks, reducing overall system complexity while maintaining full functionality.
2Device complexity
If control logic is implemented only on the primary side, then the device complexity is reduced, but the capability to receive communication signals on the secondary side is lost
Solution Approach 1:
The patent uses an isolated communication interface as an intermediary to transmit DALI communication signals from the secondary side across the galvanic isolation barrier to the primary side control logic. This allows the primary side controller to receive and process communication signals without requiring a secondary side microcontroller, maintaining electrical isolation while enabling communication capability.
Data Source
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AI summary
The invention relates to an isolated converter (10) for supplying an LED load (20). The isolated converter (10) comprises: a galvanic isolation barrier (11) which is arranged between a primary side and a secondary side of the isolated converter (10); a control circuit (12) arranged on the secondary side of the isolated converter (10), wherein the control circuit (12) is configured to operate at least one switch of the isolated converter (10); a voltage-controlled oscillator, VCO (13), arranged on the primary side of the isolated converter (10); and a voltage sensing circuit (14) arranged on the primary side of the isolated converter (10), wherein the voltage sensing circuit (14) is configured to provide a voltage level of a supply voltage to the VCO (13); and wherein the VCO (13) is configured to issue a voltage sensing signal based on the voltage level, wherein the voltage sensing signal is supplied across the galvanic isolation barrier (11) to the control circuit (12).