PFC Driver Supply Voltage Synchronization for Lower SMPS Loss
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Solution Overview
Problem
Existing driver arrangements with power factor correction circuitry suffer from high material and space requirements due to double-stage converting circuitry, and switched-mode power supplies experience significant power loss and inefficiency due to out-of-phase supply and offset signals, especially when powering LED loads with varying forward voltages.
Innovation Solution
A driver arrangement with an adjustment circuit that synchronizes the supply voltage with the offset signal produced by the switched-mode power supply, reducing power loss by adjusting the voltage in phase and amplitude to match the offset signal, using a switch arrangement and inverting circuit to control the supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple separate integrated circuits are used for different driver functions, then functional reliability is improved, but device complexity and component count increase
Solution Approach 1:
The patent combines multiple driver functions (first driver for first sub-pixels, second driver for second sub-pixels, compensation circuitry, and power factor correction circuitry) into a single integrated circuit device. This integration reduces the total number of separate components while maintaining all necessary functional capabilities, thereby reducing device complexity without sacrificing functional reliability.
2Device complexity
If conventional resistive voltage divider circuitry is used for power factor correction, then circuit simplicity is maintained, but reactive power consumption increases and voltage control precision deteriorates
Solution Approach 1:
The patent replaces the conventional resistive voltage divider circuit with a switched capacitor circuit that uses capacitive reactance instead of resistive elements. By changing the fundamental parameter from resistance to capacitance and using switching mechanisms, the circuit achieves power factor correction with minimal reactive power consumption while maintaining precise voltage control capability.
3Measurement precision
If switched capacitor circuitry is used for voltage division, then voltage control precision is improved and reactive power consumption is reduced, but circuit complexity increases
Solution Approach 1:
The switched capacitor circuit performs multiple functions within a single integrated structure: it provides precise voltage division, implements power factor correction, and controls gate voltages for the OLED sub-pixels. By making the circuit multi-functional, the patent achieves high voltage control precision and reduced reactive power consumption without proportionally increasing overall device complexity, as the same circuit elements serve multiple purposes.
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
The synchronization of supply voltage with the offset signal significantly reduces power loss in the switched-mode power supply, enhancing efficiency and ensuring consistent voltage demands are met across varying LED loads.
Implementation Method 1
a capacitor coupled to the second electrode and configured to maintain a voltage across the second electrode during a second sub-frame period
Implementation Method 2
Each OLED is configured to emit light in response to application of a gate voltage to a second electrode of the OLED
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A mechanism for controlling a supply voltage for a switched-mode power supply designed for compensating an AC mains power ripple in a PFC output signal produced by a power factor converter. An adjustment circuit is used to synchronize the amplitude of the supply voltage with the amplitude of an offset signal generated by the switched-mode power supply used to compensate for the AC mains power ripple in the PFC output signal. Said synchronizing regulates the difference between the voltage amplitude of the adjusted supply voltage and the voltage amplitude of the offset signal, thereby controlling the power loss of the switched-mode power supply.