Source Driver Precharge Circuit for Lower Display Power
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Solution Overview
Problem
Existing source driver architectures for flat panel displays consume excessive power due to the large charging distance required to reach target voltages, despite using charge sharing methods to save power.
Innovation Solution
Implementing a method where a reference voltage source charges or discharges the loading end of a source driver to a reference voltage with the same polarity as the target voltage, and an output stage completes the charging or discharging to the target voltage, reducing the power consumption by minimizing the voltage difference to be overcome.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If charge sharing method is used to reduce power consumption, then power consumption is reduced, but the charging distance remains large requiring many charges to reach target voltage
Solution Approach 1:
The patent applies preliminary action by pre-charging the loading end to an intermediate voltage level (e.g., 0.5×AVDD) before the final charging stage. This preliminary charging reduces the voltage difference that the output stage must overcome, thereby reducing power consumption while improving charging efficiency. The loading end is first charged to an intermediate level through a first charging path, then completed to the target voltage through a second charging path.
2Reliability
If operational amplifier continuously alternates between supply voltage and grounding voltage, then complete driving operation is achieved, but power consumption increases due to large voltage difference
Solution Approach 1:
The patent segments the charging process into multiple stages: a first charging stage that charges the loading end to an intermediate voltage level, and a second charging stage that completes the charging to the target voltage. This segmentation allows the operational amplifier to operate in a more efficient manner by reducing the voltage swing amplitude in the final stage, thereby maintaining reliable driving operation while reducing power consumption.
Solution Approach 2:
The patent introduces an intermediate voltage level (e.g., 0.5×AVDD) as a mediator in the charging process. The loading end first charges to this intermediate level through a first charging path, then uses this intermediate level as a starting point for the second charging path to reach the target voltage. This intermediary voltage level reduces the voltage difference that must be overcome in the final charging stage, reducing power consumption while ensuring complete driving operation.
3Manufacturing precision
If display size and resolution increase, then image quality improves, but power consumption increases due to larger loading capacitance
Solution Approach 1:
The patent applies preliminary action by pre-charging the loading end to an intermediate voltage level before the final charging stage. This is particularly effective for large displays with high resolution, as the loading capacitance is larger and would require significantly more energy to charge directly from ground to target voltage. The preliminary charging reduces the energy requirement for the main charging operation, enabling high-resolution displays to operate with reduced power consumption.
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 significantly reduces power consumption by allowing the source driver to achieve target voltages with fewer charges, particularly effective when target voltages are close to the system supply or ground voltages, thus improving efficiency as display sizes and resolutions increase.
Implementation Method 1
a reference voltage source charges or discharges a loading end of a source driver to a reference voltage having a polarity the same as a polarity of a target voltage and a voltage level near a voltage level of the target voltage
Data Source
AI summary
A method capable of reducing power consumption of source drivers is disclosed. The method includes a reference voltage source charging or discharging a loading end of a source driver to a reference voltage having a polarity the same as a polarity of a target voltage and a voltage level near a voltage level of the target voltage, and an output stage of the source driver charging or discharging the loading end to the target voltage.