Matrix Circuit Leakage Current Prevention in Display Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Matrix circuits for display devices in household appliances face issues with leakage current flowing through light-emitting diodes, which can damage or destroy them, especially when not in operation.
Innovation Solution
Incorporating first resistors in parallel with controllable switching elements in each column, ensuring a forward current is continuously fed through all light-emitting diodes, preventing leakage by keeping them in a forward-biased state, even when not actively driven, and using a minimal number of resistors to maintain simplicity and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If controllable switching elements are used to control LEDs in a matrix circuit, then the ability to selectively operate individual LEDs is improved, but leakage current flows through non-operating LEDs causing damage
Solution Approach 1:
Resistors are introduced as intermediary components connected in parallel with the controllable switching elements. These resistors provide an alternative current path that prevents reverse voltage from appearing across non-operating LEDs, thereby eliminating leakage current while maintaining the selective control functionality of the switching elements.
2Reliability
If resistors are added in parallel with each switching element to prevent leakage current, then LED protection is improved, but device complexity increases
Solution Approach 1:
Multiple resistors that would traditionally be needed for each switching element are merged into shared current paths. The circuit design allows groups of resistors to be combined into common current paths that serve multiple LEDs simultaneously, reducing the total number of discrete resistor components while maintaining protection for all LEDs in the matrix.
3Reliability
If continuous forward current is fed through all LEDs to prevent leakage, then reliability is improved, but energy consumption increases
Solution Approach 1:
Instead of continuously feeding forward current through all LEDs, the circuit uses periodic action through the switching elements. Current is applied in controlled pulses or intervals only when specific LEDs need to be operated, while the parallel resistors provide protective current paths only when needed to prevent leakage during non-operating states.
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
Effectively prevents leakage current through light-emitting diodes, ensuring their longevity and reducing component complexity and energy consumption by only applying necessary current when needed.
Implementation Method 1
ensuring a forward current is continuously fed through all light-emitting diodes
Implementation Method 2
preventing leakage by keeping them in a forward-biased state
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a matrix circuit (3) for a display device (2) of a domestic appliance (1) having a predetermined number of light-emitting diodes (D1 to D9) which are connected by means of respective supply lines (LZ, LS) in lines (Z1, Z2, Z3) and columns (S1, S2, S3). The columns (S1, S2, S3) and lines (Z1, Z2, Z3) have respective controllable switching elements (4, 6) for switching an electrically conductive connection between the respective supply line (LS) of the column (S1, S2, S3) and a supply terminal (5) of the matrix circuit (3) and between the respective supply line (LZ) of a line (Z1, Z2, Z3) and an earth terminal (7) of the matrix circuit (3). The matrix circuit (3) has for each column (S1, S2, S3) a respective first resistance (R1) which, for electrical connection of the respective supply line (LS) to the supply terminal (5), is connected in parallel with the controllable switching element (4) of the respective column (S1, S2, S3). Alternatively, the matrix circuit (3) has for each column (S1, S2, S3) at least one first resistance (R1) which, for electrical connection of the respective supply line (LS) to the supply terminal (5), is connected in parallel with the first controllable switching element (4) of the respective column (S1, S2, S3). The invention further relates to a display device (2) and to a domestic appliance (1).