Voltage-Input Microdisplay Pixel Circuit for Static Power
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Solution Overview
Problem
Existing pixel driving circuits in microdisplay panels face issues of static power consumption and limited output voltage range due to deviations in driving transistor parameters, leading to potential gate breakdown and display inconsistency.
Innovation Solution
A voltage-input pixel driving circuit with a novel configuration that includes a first transistor, a second transistor in a normally-on state, a driving transistor, a coupling capacitor, and a MUX signal gating unit, which adjusts the drain voltage to eliminate static power consumption and expand the input data signal voltage range while preventing gate breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a source follower structure is used for voltage input, then the circuit is simple, but the output voltage range is limited and static power consumption occurs
Solution Approach 1:
The pixel driving circuit is divided into distinct functional modules: a first transistor for data voltage input, a second transistor for source voltage control, and a driving transistor for current output. This segmentation allows independent optimization of each module to eliminate static power consumption while maintaining circuit simplicity.
Solution Approach 2:
The second transistor is configured in a normally-on state with its source voltage dynamically adjusted based on the light-emitting phase, enabling the circuit to adapt its operating state and eliminate static power consumption during data writing while maintaining simplicity.
2Use of energy by moving object
If the source voltage of the driving transistor is increased to expand output voltage range, then the voltage range improves, but the gate-source voltage of the first transistor becomes excessively high causing gate breakdown
Solution Approach 1:
The second transistor acts as an intermediary between the data input and the driving transistor source. By controlling the second transistor's source voltage, the circuit can expand the output voltage range while the first transistor's gate-source voltage remains within safe limits, preventing gate breakdown.
Solution Approach 2:
The circuit changes the operating parameters by using a normally-on second transistor with dynamically adjustable source voltage. This allows the driving transistor's source voltage to be optimized for expanded output range while maintaining the first transistor's gate-source voltage within safe operating limits.
3Measurement precision
If the coupling capacitor ratio is adjusted to improve voltage coupling, then the coupling efficiency improves, but the input voltage range becomes excessively low
Solution Approach 1:
The circuit changes the operating parameters by using a normally-on second transistor with dynamically adjustable source voltage. This allows the driving transistor's source voltage to be optimized for expanded output range while maintaining the first transistor's gate-source voltage within safe operating limits.
Data Source
AI summary
Provided is a voltage-input input pixel driving circuit for a microdisplay panel. The voltage-input pixel driving circuit includes: a first transistor, a second transistor, a driving transistor, a coupling capacitor, a light-emitting element, and a MUX signal gating unit. The first transistor includes a gate connected to a scan signal line (SCAN) of the microdisplay panel, a source connected to a data signal line (DATA) of the microdisplay panel, and a drain connected to a source of the second transistor; a gate of the second transistor is connected to an external bias voltage (VBIAS), a drain of the second transistor is connected to a gate of the driving transistor, a source of the driving transistor is connected to one end of the light-emitting element, the other end of the light-emitting element is connected to a common voltage (VCOM).