Pixel Circuit With Boosting Capacitor For Low Power Display Driving
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Solution Overview
Problem
Existing displays, particularly electronic paper displays, consume excessive power due to high voltage and current requirements for driving electrophoretic particles, as they lack effective methods to reduce the voltage or current values of driving signals.
Innovation Solution
The display incorporates a pixel circuit design with an equivalent boosting capacitor and scanning transistors controlled by different scanning signals, allowing the first node voltage to be boosted, thereby reducing the required voltage and current values of the scanning signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a higher voltage value is provided to drive electrophoretic particles in an electronic paper display, then the display operation is enabled, but power consumption increases
Solution Approach 1:
The patent introduces an equivalent boosting capacitor that dynamically changes the voltage parameter at the first node. By coupling the capacitor between the first node and second node, and controlling it with scanning signals, the capacitor boosts the voltage at the first node during specific time periods, enabling effective driving of electrophoretic particles while allowing the use of lower overall voltage and current values, thus reducing power consumption
Solution Approach 2:
The equivalent boosting capacitor is controlled to provide voltage boosting in advance during specific scanning periods. The capacitor is charged or discharged at predetermined times to prepare the necessary voltage conditions for driving the display unit, allowing the main driving circuit to operate at lower power levels while still achieving the required voltage for particle movement
2Reliability
If a higher current value is provided to drive electrophoretic particles, then the display operation is enabled, but power consumption increases
Solution Approach 1:
By dynamically adjusting the voltage at the first node through the equivalent boosting capacitor, the patent changes the electrical parameters of the driving signal. This voltage boosting effect allows the system to achieve effective particle driving with lower current values, since Power = Voltage × Current, thus reducing power consumption while maintaining display operation
3Use of energy by moving object
If the voltage value on the first node is increased, then the required voltage and current of scanning signals is reduced, but additional circuit components are needed
Solution Approach 1:
The equivalent boosting capacitor is controlled by scanning signals that are already present in the display driving circuitry. The same scanning signal lines that control other circuit elements are also used to control the boosting capacitor, making the existing scanning signals serve multiple functions - both their original purpose and controlling the voltage boosting, thereby reducing the need for additional dedicated control circuitry
Solution Approach 2:
The equivalent boosting capacitor acts as an intermediary element between the scanning signal lines and the display unit. It mediates the voltage transformation by storing and releasing charge to boost the voltage at the first node, allowing the scanning signals to indirectly control the voltage level without requiring direct high-voltage switching circuitry, thus simplifying the overall circuit design
Data Source
AI summary
A display and a driving method thereof are disclosed. The display includes a plurality of pixel circuits. Each of the pixel circuits includes a display unit, a first scanning transistor, an equivalent boosting capacitor, a second scanning transistor, a third scanning transistor, and a storage capacitor. The display unit receives a first reference constant voltage and is coupled to a first node. The first scanning transistor is coupled to the first node and receives a first scanning signal. The equivalent boosting capacitor is coupled between the first node and a second node. The second scanning transistor is coupled to the second node and receives a second scanning signal. The third scanning transistor is coupled to the second node and receives the first scanning signal. The capacitor is coupled between a first terminal and a second terminal of the third scanning transistor.