PFC Output Capacitor Energy Transfer for LED Driver Data Saving
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Solution Overview
Problem
Existing isolated DC/DC switching converters for LED lighting require large and costly capacitors for energy storage on the secondary side to ensure data saving during input power failures, which occupy significant space and resources.
Innovation Solution
The method involves deriving energy for data saving from the output capacitor of the power factor correction (PFC) stage, potentially reducing or omitting the secondary side energy storage capacitor by using a flyback converter to stabilize output voltage and detect input power failures, allowing energy from the output capacitor to power the save circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large energy storage capacitor is provided on the secondary side, then data saving during input power failure is ensured, but device size and cost increase significantly
Solution Approach 1:
The patent introduces an auxiliary power stage as an intermediary component that transfers energy from the primary side output capacitor to the secondary side control circuit during power failure. This mediator enables data saving functionality without requiring a large secondary side energy storage capacitor, thus resolving the contradiction between reliability and device size.
Solution Approach 2:
The energy storage function is segmented between two locations: the primary side output capacitor (which maintains larger capacity for PFC function) and the secondary side control circuit (which receives energy through the auxiliary power stage during failures). This segmentation allows the secondary side capacitor to be much smaller while still ensuring data saving capability.
2Reliability
If a large energy storage capacitor is provided on the secondary side, then data saving during input power failure is ensured, but manufacturing cost increases
Solution Approach 1:
The auxiliary power stage acts as an energy transfer mediator that eliminates the need for expensive large-capacity secondary side capacitors. By transferring energy from the primary side through this intermediary, the system achieves reliable data saving functionality at lower component costs.
Solution Approach 2:
The primary side output capacitor serves multiple functions: it maintains PFC operation during normal conditions and serves as an energy reservoir during power failures. This multi-functionality reduces the need for dedicated large capacitors on the secondary side, lowering overall manufacturing cost.
3Volume of stationary object
If the output capacitor of PFC stage is used for energy transfer, then secondary side capacitor size is reduced, but energy transfer control complexity increases
Solution Approach 1:
The control circuit detects input power failure conditions in advance and activates the auxiliary power stage before the main power stage fails. This preliminary action ensures continuous energy supply to the control circuit without interruption, managing the energy transfer complexity proactively rather than reactively.
Solution Approach 2:
The control circuit monitors the operational status and energy levels of both primary and secondary sides, dynamically adjusting the auxiliary power stage operation. This feedback mechanism optimizes energy transfer control, managing complexity through intelligent regulation rather than fixed control logic.
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
This approach reduces the size and cost of the energy storage capacitor, enabling efficient data saving operations without the need for a large secondary side capacitor, thereby saving space and resources while maintaining stable output voltage.
Implementation Method 1
deriving energy for data saving from the output capacitor of the power factor correction (PFC) stage
Implementation Method 2
using a flyback converter to stabilize output voltage
Data Source
AI summary
In various embodiments, a method for powering light sources from a input power supply through a converter circuit is provided including a primary side and a secondary side separated by a galvanic barrier, wherein the primary side includes a power factor control block with an output capacitor. The method may include providing save circuitry on said secondary side for saving operational data of the converter upon failure of said input power supply; and powering said save circuitry during saving said operational data with energy derived from said output capacitor of said power factor control block.