OLED Bias Voltage Circuit Using Buck-Boost and Charge Pump
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Solution Overview
Problem
Existing converter circuits for generating panel driving voltages in OLED displays, such as the inverting buckbooster, face inefficiencies due to high current and voltage requirements, leading to larger components and increased power loss.
Innovation Solution
Implementing a non-inverting buckbooster and charge pump configuration to generate a negative bias voltage, where the non-inverting buckbooster outputs half the target voltage, and the charge pump reverses the sign and doubles the magnitude, eliminating the need for additional regulators and reducing current and voltage stresses on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an inverting buckbooster is used to generate panel driving voltages, then the voltage can be converted, but the current and voltage requirements become high, leading to larger components and increased power loss
Solution Approach 1:
The voltage conversion function is divided into two separate stages: a non-inverting buckbooster for voltage conversion and a charge pump for voltage inversion and doubling. This segmentation allows each circuit to operate at lower, more efficient voltage and current levels, reducing overall power loss while achieving the required panel driving voltages
Solution Approach 2:
The non-inverting buckbooster acts as an intermediary circuit that first converts the input voltage to an intermediate voltage level before the charge pump performs the final inversion and doubling. This intermediate step reduces the stress on individual components and lowers the power loss compared to a direct inverting buckbooster approach
2Power
If an inverting buckbooster is used to generate panel driving voltages, then the voltage can be converted, but the components become larger
Solution Approach 1:
By segmenting the voltage conversion into two separate circuits (non-inverting buckbooster and charge pump), each component can be optimized for its specific function at lower voltage levels, resulting in smaller individual components and a more compact overall converter circuit design
Solution Approach 2:
The invention changes the operating parameters of the converter circuit by using a non-inverting buckbooster followed by a charge pump, operating at lower voltage and current levels throughout the conversion process. This parameter change allows for the use of smaller, more compact components while still achieving the required output voltages
3Loss of energy
If a non-inverting buckbooster and charge pump configuration is used, then current and voltage demands are reduced, but the circuit complexity increases
Solution Approach 1:
The circuit is segmented into two functional blocks with clear, standardized interfaces. The non-inverting buckbooster handles voltage conversion while the charge pump handles inversion and doubling, making each block independently designable and testable, which manages complexity through functional decomposition
4Reliability
If additional regulators are added to meet voltage requirements, then the voltage can be stabilized, but the device complexity and size increase
Solution Approach 1:
The charge pump circuit performs multiple functions simultaneously: it inverts the voltage polarity and doubles the voltage magnitude in a single stage. This multi-functionality eliminates the need for separate voltage regulators and polarity inversion circuits, maintaining voltage stability without increasing device complexity
Solution Approach 2:
The invention extracts the voltage inversion and doubling function from the traditional buckbooster circuit and places it in a dedicated charge pump circuit. This extraction allows the buckbooster to focus solely on voltage conversion while the charge pump handles inversion, eliminating the need for additional regulators and simplifying the overall circuit design
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 configuration reduces current and voltage demands, allowing for smaller components and lower power loss, thereby enhancing efficiency and reducing the size and complexity of the converter circuit.
Implementation Method 1
a non-inverting buckbooster and a charge pump and configured to supply a negative first bias voltage to the display panel
Implementation Method 2
The control circuit according to an embodiment is configured to generate, through the charge pump, a second voltage by reversing a sign of the first voltage and by converting a magnitude of the first voltage by a factor of two
Data Source
AI summary
An electronic device (201) according to one embodiment may comprise: a display (260); a first converter circuit (245) which includes a non-inverting buckbooster (510) and a charge pump (530) and is configured to supply a negative first bias voltage to the display (260); and a control circuit (220). The control circuit (220), according to one embodiment, can be configured to check a target first bias voltage to be supplied to the display (260). The control circuit (220), according to one embodiment, can be configured to output a first voltage corresponding to half the absolute value of the target first bias voltage to the charge pump (530) by using the non-inverting buckbooster (510). The control circuit (220), according to one embodiment, can be configured to generate a second voltage by inverting the sign of the first voltage and converting the magnitude of the first voltage by a factor of two through the charge pump (530). The control circuit (220), according to one embodiment, can be configured to supply the second voltage to the display (260) as the first bias voltage.