Synchronous Dual Mode Boost DC-DC Converter for OLED Bias Generation
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Solution Overview
Problem
Conventional OLED display panels face inefficiencies in voltage conversion during idle mode due to system cooperation issues, voltage signal undershoot and overshoot, and increased costs when switching voltage sources, particularly due to the need for a charge pump in the source driver.
Innovation Solution
A bias generation circuit with a synchronous dual mode boost DC-DC converter that selectively operates in pulse width modulation (PWM) or pulse frequency modulation (PFM) modes based on a control signal, eliminating the need for a charge pump in the source driver by controlling a linear regulator or charge pump to generate voltage signals, thereby avoiding voltage disruptions and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the synchronous boost DC-DC converter operates in PWM mode during normal mode, then the voltage conversion efficiency is good, but during idle mode the conversion efficiency becomes poor
Solution Approach 1:
The patent implements dynamic mode switching between PWM and PFM based on operational conditions. The synchronous dual mode boost DC-DC converter automatically transitions between pulse width modulation mode during normal operation and pulse frequency modulation mode during idle operation, optimizing conversion efficiency for each specific condition while maintaining adaptability across different operating states.
2Loss of energy
If voltage source switching is performed from bias integrated circuit to source driver, then conversion efficiency is enhanced in idle mode, but system cooperation issues arise due to different switching timings
Solution Approach 1:
The patent merges the charge pump function into the bias generation circuit rather than keeping it separate in the source driver. This integration ensures that voltage source switching occurs at a single location with unified control timing, eliminating cooperation issues between separate components while maintaining the efficiency benefits of charge pump operation during idle mode.
Solution Approach 2:
The patent implements feedback control mechanisms that monitor operational status and automatically adjust switching timing and mode. The synchronous dual mode boost DC-DC converter uses feedback signals to coordinate switching operations, ensuring that voltage source transitions are synchronized properly and system cooperation is maintained across different operational states.
3Loss of energy
If voltage source switching is performed, then conversion efficiency is enhanced, but voltage signal undershoot and overshoot occur
Solution Approach 1:
The patent applies beforehand cushioning by implementing soft switching techniques and voltage transition control. During mode switching between PWM and PFM, the circuit gradually transitions voltage levels rather than abrupt changes, using controlled ramping and buffering mechanisms to prevent undershoot and overshoot while maintaining efficient conversion during idle operation.
4Loss of energy
If charge pump is disposed in source driver to provide voltage signals in idle mode, then conversion efficiency is enhanced, but cost increases
Solution Approach 1:
The patent merges the charge pump function into the bias generation circuit, consolidating voltage generation components in one location rather than distributing them across multiple components. This integration reduces overall circuit complexity and component count while maintaining the efficiency benefits of charge pump operation during idle mode, directly addressing the cost and complexity issue.
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 solution stabilizes voltage signals during mode transitions, enhances conversion efficiency, and reduces costs by eliminating the need for a charge pump in the source driver, thus maintaining a stable power supply and improving operational efficiency.
Implementation Method 1
The synchronous dual mode boost DC-DC converter is selectively operated in a pulse width modulation mode or a pulse frequency modulation mode according to a control signal
Implementation Method 2
The synchronous dual mode boost DC-DC converter is selectively operated in a pulse width modulation mode or a pulse frequency modulation mode according to a control signal
Implementation Method 3
The synchronous dual mode boost DC-DC converter controls the linear regulator to generate a first voltage signal to the display panel
Implementation Method 4
The synchronous dual mode boost DC-DC converter controls the charge pump to generate a second voltage signal to the display panel
Data Source
AI summary
A bias generation circuit coupled to a display panel is disclosed. The bias generation circuit includes a linear regulator, a charge pump and a synchronous dual mode boost DC-DC converter. The linear regulator and the charge pump are coupled to the display panel respectively. The synchronous dual mode boost DC-DC converter is selectively operated in a pulse width modulation mode or a pulse frequency modulation mode according to a control signal. In the pulse width modulation mode, the synchronous dual mode boost DC-DC converter controls the linear regulator to generate a first voltage signal to the display panel. In the pulse frequency modulation mode, the synchronous dual mode boost DC-DC converter controls the charge pump to generate a second voltage signal to the display panel.