Pixel Circuit Using Reference Voltage to Reduce Display Power
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Solution Overview
Problem
Display panels, particularly OLED and MicroLED panels, consume excessive power due to driving current based on the difference between power and data voltages, leading to potential display quality deterioration from hysteresis in the driving switching element.
Innovation Solution
A pixel circuit design that determines the driving current based on a reference voltage lower than the power voltage and incorporates complementary switching elements to reduce power consumption and enhance display quality by minimizing hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driving current is determined based on the difference between power voltage and data voltage, then the light emitting element can be driven, but power consumption increases
Solution Approach 1:
The patent changes the voltage parameter by introducing a reference voltage (Vref) that is lower than the power voltage (Vdd). The driving current is determined by the difference between Vref and data voltage (Vdata) instead of Vdd and Vdata. This parameter change reduces the voltage difference across the light emitting element, thereby reducing power consumption while maintaining proper driving functionality.
2Reliability
If a driving switching element is used to control current flow, then the light emitting element can be controlled, but hysteresis occurs and display quality deteriorates
Solution Approach 1:
The patent introduces a reference voltage (Vref) as an intermediary between the power voltage (Vdd) and the data voltage (Vdata). This intermediary voltage serves as a stable reference point that mediates the control of the driving current, reducing the direct impact of switching element hysteresis on display quality. The reference voltage acts as a buffer that stabilizes the driving conditions.
3Use of energy by moving object
If the reference voltage is lower than the power voltage, then power consumption is reduced, but the circuit complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-establishing a reference voltage (Vref) that is lower than the power voltage (Vdd) before the actual driving operation. This reference voltage is generated in advance and stored or maintained as a stable reference level. By preparing this reference voltage beforehand, the circuit avoids the need for complex real-time voltage regulation during operation, thus reducing overall circuit complexity while achieving lower power consumption.
Data Source
AI summary
A pixel circuit includes a light emitting element, a first switch connected to first, second and third nodes, a second switch applying a data voltage to the second node in response to a writing gate signal, a third switch connecting the first and third nodes in response to a compensation gate signal, a capacitor connected to the first and fourth nodes, a fifth switch receiving a power voltage and connected to the second node, a sixth switch connected to the third node and an anode of the light emitting element, an eighth switch receiving a reference voltage and connected to the fourth node and a ninth switch receiving the power voltage and connected to the fourth node. One of the eighth and ninth switches is an N-type transistor and the other is a P-type transistor. Control electrodes of the fifth and sixth switches receive different signals.