Display DAC Gamma Voltage Segmentation for Lower Power and Area
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Solution Overview
Problem
Existing display devices face challenges with high power consumption and large size in their data driving circuits, which affect the efficiency and performance of display panels.
Innovation Solution
A digital-analog converter is introduced in the data driving circuit, comprising a gamma reference voltage generator, voltage selector, first and second amplifiers, and a boosting circuit, which includes resistor strings and switching circuits to generate and convert gamma reference voltages efficiently, reducing power consumption and circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional data driving circuit is used, then the display device can function properly, but the power consumption is high and the circuit area is large
Solution Approach 1:
The digital signal is divided into two groups: a first-group signal (most significant bits) and a second-group signal (less significant bits). The gamma reference voltage generator processes the first-group signal to generate multiple gamma reference voltages, while the voltage selector uses the second-group signal to select one of these voltages. This segmentation allows the circuit to handle different bit significance separately, reducing overall power consumption while maintaining display functionality.
Solution Approach 2:
The gamma reference voltage generator pre-generates multiple gamma reference voltages based on the first-group signal before the final selection is made. By preparing these voltage options in advance, the circuit avoids the need for high-power operations during the selection phase, thereby reducing overall power consumption while ensuring the display can function properly.
2Area of stationary object
If a conventional data driving circuit is used, then the display device can function properly, but the circuit area is large
Solution Approach 1:
The circuit is segmented into functional modules: gamma reference voltage generator, voltage selector, first amplifier, boosting circuit, and second amplifier. Each module handles a specific part of the conversion process, allowing for compact layout and reduced overall circuit area while maintaining full display functionality.
Solution Approach 2:
Multiple functions are merged into integrated circuits: the gamma reference voltage generator combines resistor strings and switching circuits to generate multiple voltages; the voltage selector integrates switching elements to select and output the appropriate voltage; amplifiers and boosting circuits are combined to achieve voltage conversion and buffering in a compact manner, thereby reducing total circuit area.
3Use of energy by moving object
If power consumption is reduced, then energy efficiency improves, but conversion precision may be affected
Solution Approach 1:
The circuit dynamically adjusts its operation based on the input signal characteristics. The boosting circuit selectively applies voltage boosting only when needed (based on the first-group signal), and the voltage selector dynamically chooses from pre-generated gamma reference voltages. This dynamic operation reduces average power consumption while maintaining conversion precision through selective high-precision operations.
Solution Approach 2:
The circuit changes operational parameters dynamically: the gamma reference voltage generator produces different voltage levels based on the first-group signal, the voltage selector changes which voltage is output based on the second-group signal, and the boosting circuit adjusts the degree of voltage amplification. These parameter changes allow the circuit to maintain precision while operating at lower power levels for extended periods.
Data Source
AI summary
A data driving circuit of a display device includes a digital-analog converter which includes a gamma reference voltage generator to output gamma reference voltages in response to a first-group signal of a digital signal, and a voltage selector to output, as a gamma selection voltage, one of the gamma reference voltages in response to a second-group signal of the digital signal. The data driving circuit also includes a first amplifier to receive the gamma selection voltage and to output a first conversion voltage, a boosting circuit to convert the first conversion voltage into a second conversion voltage in response to the first-group signal of the digital signal, and a second amplifier to receive the second conversion voltage and to output an analog signal.